Atmospheric Surface Damage Explained

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Glass surfaces are seriously vulnerable to the chemistry of atmospheric conditions.  There are molecular contamanents in the air that can form various monolayers on the glass.  Some of these will  cause the surface to become more easily damaged by wear when for example two plates are slid past each other during storage.   Or certain other monolayers can actually “lubricate” the surface making the surface more resistant to wear or scratching.   The difference between whether such molecules cause a lubricating effect or what is called “interfacial wear”, depends on whether they are adsorbed to the surface or actually react with the surface.   Sometimes these monolayers will cover virtually the entire area of the glass plate, and sometimes only localized “patches” are covered. 
It is also true that water molecules are quite capable of changing the “mechanochemical” properties of glass surfaces. This can happen with liquid or vapor.  There is a chemical reaction involving ion exchange.  This involves the swapping of sodium atoms in the glass surface and the hydrogen atoms in water molecules.  This process is called “weathering” also “glass corrosion”.  It is greatly enhanced by temperature and time.  This condition can reveal subsurface damage or a change in the molecular matrix of the glass at that level.  It can also cause such a change in the molecular matrix including oxygen and silicon atoms.  As window cleaners in the great north east know, old storm windows are much more rough to the touch of a dry fingertip outside rather than inside.  This is the weathering effect.  What most do not know is this particular effect begins immediately when the glass comes off the bath of molten tin.  It also can become rather severe under the right atmospheric conditions.  When glass is stored for six months before installed on the building it should be kept in a very dry, cool environment.  The glass sheets should be kept separated from one another by what is called an interleaving system. 
The point that I am attempting to make here is that glass surfaces are certainly not chemically and physically inert and unchanging.  They are in fact quite alive with activity.  The chemistry of the surface can be so altered by atmospheric conditions that certain previously damaged “subsurfaces” are preferentially exposed to physical attack by whatever means. Also various monolayers of atmospheric pollutants form monolayers that will either enhance the likelihood of mechanical damage to the surface or actually lubricate it and actually protect it from such damage.  
I know from my own experience that when glass is polished with an optical silica based compound or a cerium oxide, it becomes rough to the touch.  It also becomes much more water loving.  This same exact condition can be caused by a very dilute solution of hydrofluoric acid.  Once it is created either physically , chemically, or both;...the glass surface takes on an alternate “microtexture”.  If this condition is measured on a level less than a micron it is called a “nanotexture”. Microtextured surfaces are much more prone to surface damage.  Whether that be interfacial shear,  stress cracks, or scratches.  It is also possible to apply certain “lubricating” monolayers to microtextured surfaces using silane chemistry. Once applied correctly the monolayer will not just adsorb but react with the nonbridging oxygen atoms and resist mechanical wear, and scratches.  Many years ago I discovered a product created by DuPont in Wilmington Deleware that did precisely this.  It was based on a highly concentrated water based alkyltrialkoxysilane and tetraalkylammonium chloride.  This product was so concentrated that I could actually reduce it by 100 times with pure water and get the same effect on glass.  If applied correctly that is, by first microtexturing the surface, and then rubbing the silane solution into the micropores so as to effect the maximum number of reactions with the nonbridging oxygens.  I also discovered by testing other glass sealants that they did not have the same effect.  So chemistry is very important and necessary to properly protect glass surfaces from mechanical wear or scratches. Protection from the weathering effect of humidity/water can be accomplished with a variety of glass sealants.
I have also learned by talking with “true” glass restoration professionals that window glass surfaces which are prone to scratches can be “fixed”.  This is done by means of a grinding and polishing process.  It follows then from what we have learned thus far that such surfaces can now be both “repaired” and protected from further scratches.  The surface and subsurface can be precisely re-engineered and then chemically sealed by a reactive silane chemistry.  You will find some of the gurus of this science/technology on the Glass Smart Facebook Group.

Written by Henry Grover Jr.
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Unlocking the Secrets of Transforming Hydrophobic Glass to Hydrophylic.

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The true key to being able to use a WFP on windows without a resin bed or R/O system is hydrophylic glass.  This can be done three different ways.  First we can seal the glass with a hydrophylic coating or simply put chemically treat it.  Or we could inject a Super Soap into the feed line of a WFP to dramatically reduce the surface tension of whatever water we are using, even tap water.  Or as I am discussing in this post, we could microlap the glass with SKRUB.  This physically deep cleans the glass by removing all hydrocarbon groups and what is called the near surface.  The glass takes on its natural hydrophylic property which is actually enhanced because the micro-surface is now even more rough.  There is essentially more surface area of glass per square cm for water to cling to.


First Clip

Second Clip

The full length Video

To apply SKRUB I first wet the glass with any type of cleaning solution.  Then I put a few drops on the back of the flat hard felt pad.  I use an F1.  About 1/4 inch thick.  I have glued a piece of 1/4 inch masonite to the back of this Makita random oscillating sander.  It operates at about 10,000 OPMs.  Then I glue the felt to the Masonite.  Any other soft wood will do.  Pine is especially useful.  Now just go to it.  The SKRUB will instantly mix with the cleaning solution making a perfect slurry.  You can more easily control how much you use this way also.  Further this techniques will not throw your polishing slurry all over the room.  You will notice you can work right up to the edge of the glass without any mess.  When done just soap and squeegee off.  The glass wil be perfectly clean.  You can even feel the difference.  The polished side will be much more rough.

Now it takes not more than a minute per square foot to polish. Also it takes about 1/8 of an ounce of SKRUB to polish a square foot.  So an 8 ounce bottle of SKRUB will do about four large sliding glass doors.  Maybe more because SKRUB is a highly concentrated polishing compound.

The quality of the finished surface is quite high.  If you look at the two clips here again you will see how water completely sheets over the surface.  There is absolutely no beading.  This is what we need for WFP work.  The only drawback is the cost in money and time to set up the windows ahead.  It is a permanent treatment.  But if we can't get the customer to pay, and we are not going to be cleaning the windows frequently enough at a high enough profit, then it would not be worth the expense.  In which case one of the other two alternatives might be the better answer.  

Written by Henry Grover Jr.
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SKRUB Product Development Review

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The Product Development Review

SKRUB

SKRUB is a microcrystalline silica particle suspended in pure glycerin.  There isn’t any water added.  Also the microcrystalline silica particle is just the right size and purity such that it will not scratch glass when used by hand.  There is a chance of creating a haze of scratches if used with a machine. Even ultra pure optical grade white cerium oxide can create a scratch haze if used incorrectly with a machine.  I have seen people take dry cerium right out of the box with a rotary felt pad and rip into the glass with the edge of the polishing pad. This and other similar techniques can create a haze of scratches that sometimes are completely invisible until the sun shines directly on the window.  Which is the reason why I developed my Wobble Wheel.  When used in a rotary drill motor it will keep the circular pad completely flat on the glass at all times. 
When using SKRUB with a rotary drill I will first clean the window, then wet it again with a clean soapy solution.  The soapy water will mix with the SKRUB creating a polishing slurry on the glass as you go.  Next I will add about four to six drops of SKRUB to the felt pad.  Then just polish the glass keeping the pad always flat at all times.  NEVER work the glass with the pad turned on edge.  You can soap and squeegee as you go to see if the glass is cleared of stains.  When done just soap and squeegee.  Wipe the edges or at least the bottom edge.  By polishing this way you will use only as much compound as you need, and will reduce the amount of time needed for cleanup. 
SKRUB is also intended for use as an additive for your window cleaning solution.  It can be used at one ounce per gallon of window cleaning solution.  It doesn’t matter what commercial rinse you are using.  Whether that be GG4, Ecover, Dawn, Joy, or some other mix.  You can add enough to an entire bucket and clean the entire window with it.  But the more cost effective way is to have two applicators.  Then use a squirt bottle filled with your favorite solution with a very small amount of SKRUB added to it.  Adjust the concentration to the difficulty of the job.  Then just squirt enough on the applicator and SKRUB just that area of the window that you might have used a razor blade or 0000 steel wool on.  Squeegee to make sure the greasy prints are gone and you have the correct concentration. Next soap up the entire window with the solution in your bucket using the first applicator, and squeegee.  Choose a squirt bottle you can float in your bucket.  Or a smaller one you can fit in your pocket. 
Another application for SKRUB is screen stain.  I will make up a concentrated solution of SKRUB in a squirt bottle.  Then I will SKRUB a clean window that has “screen stain” on it.  This is the stain that develops from aluminum screens.  You can use a sponge, or 0000 steel wool.  Then soap and squeegee again. This is the most safe way to remove screen stain.  If you treat the surface with a sealant like Rain X, when the stain returns one year later, it will be much easier to remove using SKRUB. And the Rain X will usually remain.  If not just reseal.  You will know when you are breaking through the stain because the solution of cleaner and SKRUB will start to bead up.

Written by Henry Grover Jr.
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Spot Free WFP Window Cleaning without Resin Tanks or RO

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Eliminating resin tanks and RO units greatly reduces the expense and increases the efficiency of cleaning windows with a water fed pole.  Since we obviously will then be working with water that has a high TDS or a high silica content, the only way to accomplish this is to eliminate the water drop and hence the resulting hard water spot.  This can be accomplished in three different ways that I know of.  First it can be done by bringing the water tension of our cleaning/rinse solution down to 20 to 25 dynes per cm.  Water typically is around 72 dynes.  Second it can be done by coating the glass surface with a hydrophylic sealant. Third it can be done by physically removing all residue from glass.  Which involves "microtexturing" with a microcrystalline silica slurry, optical grade cerium oxide, or some other superabrasive based polishing agent.  I can also see the possibility of combining these different techniques for an optimum effect and the elimination of certain problems.  Such problems however must be addressed.

The first technique involves the use of what I have been calling a Super Soap in my posts on the Window Cleaning Resource forum.  These are typically super wetting surface active agents based on a silicon or fluorine chemistry.  I and others have been experimenting with a silicon based nonionic super wetting surfactant.  Under perfect conditions of high humidity and shade it will do precisely what the title of this post says. Although these conditions are not easy to meet.  This certain surfactant will also leave behind a surfactant residue that will easily turn white if the dry window is rubbed with anything. Once the rinse/cleaner dries the window is perfectly clear and the residue is invisible.  My thoughts are that this is happening because of the electrical charge of the surf.  So I am looking into other surfs now.  The main benefits of this technique is the simplicity of it.  All we do is add the surf to a water holding tank.  We can use any tap water.  Also we don't have to invest in resin tanks or RO systems.  Which I understand present unique problems to Window Cleaners that work in desert environments.

The second technique involves sealing the glass.  This might involve superabrasive cleaning and microtexturing to initially set up the glass for application of the hydrophylic sealant.  If so it will require much time. After the initial application it will be necessary to periodically renew such coatings.  Which can be done during the cleaning process.  That part will not require any additional time.  But it is still needed.  Because there isn't any sealant on the market that will last forever.  Another problem that is true for all three techniques is the build up of minerals on the glass.  They will not form spots.  But do coat the entire plate becoming concentrated at the bottom of the windows.  They are much easier to remove with mild superabrasive products from sealant surfaces.  This is because deposits are always easier to remove from a sealant rather than glass.  Also they will not be concentrated in the form of spots. In fact they should be completely invisible until they build up

over time.

The third technique involves physically polishing the glass.  It will become naturally hydrophylic.  No surfs or sealants will be needed to cause water to sheet over the entire window and drain off leaving no spots.  There are still drawbacks to this technique.  One involves the different conditions outside.  Such can change the purity of this new surface.  Causing it to loose its hydrophylic properties.  So it might be necessary to periodically polish.  The time involved might preclude using this technique.  Especially if it is a large building with many windows, and the owners only want a yearly maintenance cleaning.

My thoughts are to combine these techniques to come up with a system that will work for each individual building/job.  It all comes down to numbers.

Written by Henry Grover Jr.

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Abrasives and Window Cleaning

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Abrasives are absolutely critical to cleaning windows.  Few manufacturers have made a study of them however.  I have written several articles on the technology of abrasive particles. Take a look at this one web site.  http://abrasive-media.com/article.php?pid=25&cid=28 This company obviously is in China where Perry lives.  Their focus is on iron sand abrasives used in blasting.  If you read about the attention paid to the properties of the particles you will see how such controls the performance.

There is a great deal of difference in the purity of size, hardness, friability, shape, functionality, and chemistry of micro and nano particles.  All of these properties control how well they "cut" through the surface, how smooth that new surface will be, whether there are particles that stick together forming much larger particles (agglomerates) that will leave errant scratches, how efficient the slurry will be, and so many other properties.

But why are they important for window cleaning?  Well have you ever used a magic sponge from Mr. Clean?  If so you were working with an abrasive impregnated sponge.  Have you ever worked with a plastic scrub pad from 3M?  This is a type of plastic abrasive.  Most likely nylon.  Possibly impregnated with silica particles.  We will never know exactly what because 3M doesn't tell anyone anything.  What of steel wool?  Most of us use 0000 steel wool.  This is an abrasive.  Each extremely fine strand of wool is only 20 microns in diameter.  Further it has a peculiar shape which allows it to do its work.  According to this video they are razor sharp and have a triangular shape.  It is my guess that they leave very few if any scratches at 0000 because wool is not based on a particle but rather a strand.  So rather than cut it rubs.  Kind of like really small razor blades. The problem we have is that they rust so quickly.  Leaving a red stain on white vinyl frames or paint.

If you look into compositional abrasives you will find some fascinating animals out there.  Such as plastic abrasives.  These are softer than glass, but are rather sharp.  So they cut through stuff like cured silicone caulk, paint, and wood stain.  Add a solvent like DLimonene at 90% purity and you have an effective tool.  It also won't rust. The problem that I have with acrylic particles for example, is they are only sold down to 177 microns.  Maybe 100 microns.  But I want them down to 20 or even 15 microns.  That would be equal to around 600 to 700 mesh.

Regarding compositionals there are also some very hard woods like walnut shell.  These are much better for the ecology.  The only problem is they do tend to absorb water and can become soft.  They also are difficult to get as a very fine micronized powder.  Nonetheless I do see them as a possible creative solution to various problems.

Here is another fascinating abrasive idea.  Actually using frozen carbon dioxide particles as a blast medium for cleaning various surfaces.  I wonder how it might work on glass. http://www.coldjet.com/

One thing I am working on now is removing hard water spots from glass sealants.  I first want a hydrophylic silane sealant that can be applied to the glass once it has been polished.  The sealant should be water miscible so it will go on quickly with our cleaner.  Soap, squeegee and you're done.  This sealant should also stand up to high pH water runoff from concrete or groundwater.  Then the applicator used to clean must also remove any newly formed hard water spots using some type of abrasive.  That abrasive coupled with the new surface treated with a sealant should release the new spots.  Further the cleaning solution will put down a new silane treatment for the next cleaning.

This is not just an idea.  I have already had success with screen stain (which is an aluminum dioxide deposit), Rain X, and 0000 steel wool.  All I need to do is change the players for concrete efflorescence and sprinkler system spots.  The abrasive should not be one that will remove glass.  It must not be that aggressive. Rather it should be aggressive enough to remove the new spots from the silane coating.  Hopefully it also will not remove much if any of the silane.  But the solution that is used to scrub with (clean) will also put down another coat of silane.

Written by Henry Grover Jr.
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Creating Hydrophylic Glass Surfaces

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Why would someone want to make glass hydrophylic?  Simply because a surface that causes rain water to sheet instead of bead will not spot.  It would be easier to keep the window from developing hard water deposits.  Also to just keep it clean in general.

As it turns out window glass is typically hydrophylic by nature. One reason why it is seen to be hydrophobic is the presence of different water hating contaminants.  So one very easy way to make it hydrophylic is to polish it with a cerium oxide or other polish.  According to Marc Tanner this is a rather permanent solution to the problem.  Surprisingly it is a rather quick process too.  Taking just a matter of several minutes per window.

Another way to make glass hydrophylic is to hit it with a very dilute concentration of hydrofluoric acid.  Down to just 1 percent.  This will clear the glass of everything and etch it.  The glass will become very hydrophylic.  Although I would never suggest doing this I bring it up here just to help with the idea of hydrophylic glass surfaces and what is involved in creating them.

Another way to create such a surface is to use an organosilane that would react with the glass and form a hydrophylic coating. Preferably one that would last for some time and not be degraded by ultraviolet radiation.  Likewise one that would not be attacked by the high alkaline pH of ground water.  I don't think longevity would be very important if we were able to apply it every time the windows were cleaned.  I know a silicon chemist up in Canada who tells me anything is possible. The bottom line here is how much money would the company make off creating such a product?

Another solution would be the cleaning solution itself.  If it were based on what I call a Super Soap otherwise known as a Super Wetter, we could make the cleaner/rinse sheet over even hydrophobic surfaces.  And do this at very low costs.  Here we are not addressing the glass surface but rather the cleaning solution itself.  These Super Wetting surfactants are even capable of sheeting over surfaces that have been treated with products like Rain X.  As Malcolm says "Work Wiser With Wetter Water"!   

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Written by Henry Grover Jr.
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Join my Facebook Group Glass Smart Products!

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I have started a Facebook Group called Glass Smart Products for anyone who would like to become a Beta Tester of the products I am developing for the Window Cleaning Industry. All you need to do is email me your shipping address and I will get back to you about the sample and how much I need to ask for it.  It does cost me for shipping and takes time out from my work cleaning windows so I have to ask for some compensation. When you recieve the sample please test and write about your experience on my group.  Also you can write about it on the WCR Forum at www.windowcleaningresource.com 
The link for my facebook group is 
https://www.facebook.com/groups/1730279803903497/ 

Written by Henry Grover Jr.
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Glass Smart Consulting

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A Glimpse of the Ghost Particle?

For decades now it has been the belief of the Window Cleaning Industry that fabrication debris or microfines are the reason for defective glass surfaces which are rough and are very easily scratched during the cleaning process.  It is in fact still the belief of many that this happens in the tempering factories where it is said the glass picks up the particulates of glass resulting from the cutting process before the sheets are tempered.  Then these particulates and possibly other particulate debris are by means of the rollers in the tempering oven, driven into the semi viscous flat glass surfaces.  Where they essentially fuse once the glass cools down to room temperature.  Is this the truth or is it a misguided lie?  If you ask most Window Cleaners you will learn very fast that they don’t care.  They simply would like it stopped, and have some means of working with the defective glass that has already made it into buildings all over the world.  They have become totally exasperated by the lawsuits that have resulted and the burden of dealing with this problem.  Which by the way is absolutely not limited to the use of metal razor blades.  I have personally witnessed defective surfaces scratched by plastic 'blades', and 0000 steel wool.  I have also heard reports of scratching resulting from soft cotton cloths!

For many years now the Glass Committee of the International Window Cleaning Association (IWCA) has been focused on learning what the real answer to this problem is.  It couldn’t be more obvious to everyone  within the Window Cleaning Industry and the Glass Industry that this is a problem.  What we all would like to know is precisely what it is, and how can it be stopped?  Also, can the damaged surfaces which are already installed actually be repaired?  The IWCA deserves the full support of every single window cleaner in this world.  Simply because they have taken on the challenge and the burden of getting the scientific answers to these questions.  Spearheaded by Paul West and Paul Duffer, along with the help of others, they have spent many hours and dollars setting up special tests to learn the truth.  The last series of tests just finished involved attempting to embed and fuse glass microfines into a semi viscous plate of glass during the tempering process.  In this they failed miserably.  Yet they succeeded in my opinion in proving that the old idea about microfines and tempered glass is quite wrong.  There is something else at work here.  Now I know this is absolute heresy to many people.  So I am not going to win their applause.  But let me present you with some very interesting ideas.  Some of which you might not be aware of.

The only other process to look at is the float process.  It is called the float glass process because the glass actually floats down a river of molten tin called the ribbon.  This is where flat glass is actually made.  The float glass line was originally developed back in 1959.  One year after I was born.  

                                                        

Each line/factory will produce 300 to 600 tons of product a day.  It begins by heating the batch of silica, limestone, soda ash, dolomite, and cullet to about 2900 degrees Fahrenheit.  In a matter of minutes!  So far so good.  Next the melted glass goes through the fining process.  During this 'fining' process bubbles that result from the melting of the batch actually rise ‘to the surface’ and escape into the atmosphere of the furnace.  In fact it was stated in one of the videos I watched that the processes within the furnaces are managed from the control room to ensure that the glass is homogeneous and free of bubbles.  This is interesting.  I could ask several questions at this juncture.  Another interesting statement made was that heating in the float bath is carefully controlled to ‘melt out’ any roughness in the glass.  In fact to produce excellent quality glass one must control its cross ribbon temperature and associated viscosity. 

When the glass passes onto the liquid tin bath it is around 1900 degrees Fahrenheit.  It leaves the float bath at about 1,000 to 1,100 degrees and enters the annealing oven or lehr.  It then comes out of the other end of  the annealing oven at between 200 and 350 degrees.  I know some of you are mouthing the words rollers at this point.  But the manufacturers state that once the glass comes out of the float bath chamber at 1,000 degrees it is hard enough so that the rollers that move it through the annealing oven cannot do damage to it.                                                            

Annealed glass should not be allowed to vary more than five degrees.  So the rate of cooling as it passes through the annealing lehr must be very closely controlled.  If you check out the control room on the Pilkington video I have embedded here you will notice it looks more high tech than the Bridge of the Enterprise in Star Trek.  Not for no good reason!  Sure it is just a ribbon of glass.  But all of the processes  involved in controlling the flow rate, temperature, and the chemistry of the barrier gas in the float bath chamber;...must be very carefully and precisely controlled.

Oh yes.  I haven’t mentioned anything about the chamber gas of pressurized hydrogen/nitrogen yet.  Very simply put, the reason for the use of this gas in the float chamber is to prevent oxygen from contaminating the liquid tin.  This however does have a direct effect on the glass surface.  There is actually an exchange that goes on consistently between the chemistry of the tin and that of the glass surface.  Such that even the mechanical hardness of the tin side is greater than that of the air side.  Which has been proven by a very accurate scientific test.  A harder surface is not necessarily a bad thing which it isn't, but consider this statement made by Weissmann Rudolf in a paper called Fundamental Properties of Float Glass Surfaces;  “...the tin and atmosphere sides show a slight difference in their strength that comes from the contact of the tin side with transport rollers. In addition, since the ribbon is molten and deformable along almost the whole length of the bath, any specks falling from the bath atmosphere or any bubbles rising through the molten tin will permanently damage the surface.”.  Now that last sentence is worthy of note.  Specs from the bath atmosphere falling onto the surface or bubbles rising to the surface.  Remember that ‘bath atmosphere’ is a pure nitrogen/hydrogen gas under pressure.  Here is a very interesting statement from Walker Textures, a company that specializes in professionally etching glass and mirror.  “Float glass is best etched on the 'atmosphere' side of the sheet, due to the increased likelihood of impurities and/or surface imperfections on the 'tin' side of the sheet.”.  If their customers want the glass etched on both sides they will not guarantee the quality of the entire job.  Just the air side.  Not the tin side.  At this juncture I will quote Stewart Engineers .  They state, “All tin baths are uniquely designed and operated which results in a wide variance of glass product quality.”.  In fact the technology used in the float glass process is considered intellectual property, and is licensed.  Float lines cost about 120 million to build new, and cost about 360,000 to rebuild.  Which must be done every 10 to 12 years.  There must be a good reason to rebuild after ten years.  Also if you have one that is producing high quality glass, I don't think you would be so inclined as to tell your competition about the details of its operation.

So there you have it.  Are you beginning to get a glimpse of the Ghost Particle?  Did you know that the UK and other Countries are very familiar with defective ‘float glass’ surfaces?  Why they even have a classification system for the different individual defects/inclusions.  This box was created by a company called Dark Field Technologies.  

This next picture was taken with a polarized microscope from Leica Microsystems.

Leica sells many different types of microscopes, also polarized microscopes which are favored by glass inspection companies that specialize in detecting surface defects/inclusions.  Which can also be seen when they are just below the surface using a polarized microscope.  As in this colorful picture above.

  

This next picture is a Scanning Electron Microscopic image of a nickel sulfide inclusion.  It came from the website of a company in the UK called Glass Technology Services.

  
Stones, knots, cord, ream, blisters, seeds, airlines, metallic inclusions, and raw material contaminants.  These are all terms JTF Microscopy Services uses to identify various glass defects.  They also use Polarized Microscopy.  Checkout this somewhat scary picture below.  It is an SEM (scanning electron microscope) image at 3,000x of a wafer defect taken with the e-RAM.  Taken by a company called SEM Tech Solutions. 

The same company also created this very colorful Birdseye 3D image at 3,000x of the preceding SEM image taken with the e-RAM.

I would like to quote Kathryn Gromoski of Penn State 2010 in an article she wrote entitled, "Glass Breakage-Nickel Sulfide Inclusions".  "It is at the very beginning of the life of the glass that inclusions are introduced. Inclusions are microscopic particles that are incorporated into the structure of the glass in the initial heating process. According to the Glass Association of North America (GANA), there are approximately 50 different types of dirt or other inclusions recognized, but almost all of them are completely harmless (Johnson 2008). Nickel sulfide is the only exception, and even then it is only a problem in tempered glass.".  

Here is the link to the entire article

https://www.engr.psu.edu/ae/thesis/failures/MKP/failures/failures.wikispaces.com/Glass_Breakage_Nickel_Sulfide_Inclusions.html

Notice that she states that these particles are introduced at the very beginning of the ribbon.  Not during the tempering process.  She also does NOT call them defects but rather inclusions.  Although as inclusions they are still 'microscopic particles'.  Of which there are about fifty different kinds.  That is a virtual zoo of particles!  But even so they are still quite harmless.  By whose standards?  By the glass manufacturers of course.  Unless these happen to be nickel sulfide inclusions they won't cause glass breakage.  Even nickel sulfide is considered harmless unless it ends up in tempered plates down the line. Only then can it cause breakage.  Simply put glass manufacturers do not want to see these inclusions or microscopic particles as a defect.  The microscopic quality of the surface of float glass (which is recognized by different industries as the tin side) is not really very important.  As long as the glass isn't going to spontaneously explode or the window implode, the glass manufacturers are cool with it.  There might be a problem here if it was not so easy to coat the air side of float glass.  The air side which faces up is coated right on the tin bath.  This brings me to another interesting thought.

It is the practice of the glass manufacturers to NOT coat the tin side.  Also the coated (Low E) side is usually facing in on IG (insulated glass) units.  That is either the 2nd or 3rd surface. Which means the tin side will be facing out.  There is a special UV lamp which is used to locate the tin side.  This is significant because if the tin side were facing in we likely would not have many defects (or inclusions) to deal with.  Although it is good to remember here that it is possible for 'specs' to fall onto the air side of float glass in the float glass chamber.  This happens when the chamber air becomes contaminated by the tin.  

Now lets take a look at what the IWCA has been up to.

Under the direction of Paul West, the chairman of the Glass Committee, there were several different samples of windows with and without scratches taken from different parts of the country, and submitted to Penn State University as a summer project.  The purpose of this project is to learn why some glass surfaces appear to be more rough than others.  Also what are the actual features of such "rough surfaces" that cause window cleaners to make this claim? At one facility it was learned that some glass scratched and other glass on the same building did not scratch.  The obvious question is what are the underlying surface properties that could account for this?  Another question would be, is there something unique about certain glass surface properties that make it easy for amorphous silica and silicate particles in the environment to scratch such a surface?  Also, might these surface properties be responsible for the variety of scratched windows mentioned earlier?  Further, are these questionable surface properties connected only with heat strengthening and tempering of glass? Or are such rough problematic surfaces formed on the tin side of the float glass ribbon early in its life?

This very specialized field of glass defect/inclusion analysis and inspections is a technology that I will continue to explore. There will be more articles that I will be writing on the 'Ghost Particle' that will be posted in this blog.  This is just the beginning.  I think you all have realized by now that this problem is here to stay.  As Window Cleaners we need an accurate understanding of exactly what the Ghost Particle is. We know at this juncture that it absolutely is not a ghost.  It is in fact quite real.  It is also likely that it will have multiple identities.  I truly do not believe in ghosts anyhow.  We also desperately need to be better equipped to accurately identify the condition and quality of the surface of the windows we are working on. Those which are prone to scratches should be discovered before installation of course. However if such problematic windows have already been installed, we also need to have methods for working on them as safely as possible with the best tools and green chemicals.  Lastly I have heard that it might be possible to perfect a system/method for restoring these surfaces by grinding, polishing and sealing with a scratch resistant silane.  More on this later.

I would like to take this opportunity to thank the IWCA Glass Committee and all its members for taking the last eight years to explore this very important issue.  It has a direct impact on every window cleaner in the world.  For this reason everyone should become members and support the educational work of the IWCA. 

International Window Cleaning Association
Mr. Paul West / Chairman
Glass Education Committee
1100-H Brandywine Blvd
Zanesville, OH 43701-7303
800-875-4922 / www.IWCA.org
Stewart Engineers
11640 NorthPark Drive, Suite 100
WakeForest, NC 27587
(01)-919-435-9100 / www.StewartEngineers.com

Dark Field Technologies
70 Robinson Blvd.
Orange, CT 06477
203-298-0731 / www.darkfield.com

Walker Textures
9551 Ray Lawson, Montreal QC
Canada H1J1L5
888-320-3030 / walkerglass.com
Leica Microsystems
1700 Leider Lane
Buffalo Grove, IL 60089
800-248-0123 / leica-microsystems.com

Glass Technology Services
9 Churchill Way, Chapeltown
Sheffield, South Yorkshire
S352PY United Kingdom
44-(0)-114-290-1801 / www.glass-ts.com
JTF Microscopy Services
9064 Wixson Rd
Hammondsport, NY 14840
607-731-8863 / jtfmicroscopy.com

SEM Tech Solutions
6 Executive Park Drive
North Billerica, MA 01862
978-663-9822 / semtechsolutions.com
Written by Henry Grover Jr.
henrygroverjr@gmail.com
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The Cause of Scratched Glass-A Quest for Answers By Paul West

Send your email for a copy of the Glass Smart Insider to henrygroverjr@gmail.com

For decades now, window cleaners have reported encountering glass with a “rough surface” that has a “drag sensation” and exhibits a “tinkling sound” when a razor blade is passed over the surface.  This type of surface has historically been described as  fabricating debris in varying amounts. Historically, “fabricating debris” has been described as particles that were not adequately washed off prior to entering the tempering oven, thus getting fused or “baked” onto the surface. However, research by the IWCA in recent years has shed light on some inconsistencies in that theory.

First, lab tests that attempted to fuse glass particles and sand to flat glass failed. After heating and cooling glass contaminated with particles failed to produce the fusion.

Second, powerful microscopes attempted to detect fused particles on actual samples of offensively scratched glass from the field. No such particles could be identified.

Third, after more than five years of searching, no actual physical specimens of glass tainted with fused fabricating debris have been delivered to the IWCA. However, we were able to gather scratched glass samples from actual construction sites in all parts of the country.  Sure enough, these scratched glass samples exhibited a “rough surface” whereas many times similar glass windows on the same job site exhibited a smooth surface and did not scratch even though the same cleaning methods were used.

Fourth, at last years IWCA Convention we introduced the idea that the rough surface of glass that appears more likely to scratch could be due to a change at the micro or nano level, and the term nanoscale roughness was introduced. There is an entire field of science that discusses how surfaces with a nanoscale roughness may be more prone to physical damage.  The question remained however - how do the “rough surfaces” that are encountered in the field originate? Do they develop during the tempering process? Or are there other considerations? Could the development of such nanoscale roughness go back to the actual float glass process where glass is made on a bed of molten tin - producing what is known as an “air side” and a “tin side”?

It is interesting to note in the IWCA collection of scratched glass with “rough” surfaces the tin side usually corresponded with the rough side, which corresponded with the scratched side.  Should this surprise us? Is it possible that the tin side of float glass can develop a "random roughness"?

To begin to understand this, I direct your attention to the paper “Statistical Analysis of the Metrological Properties of Float Glass” by Brian W. Yates and Alan M. Duffy. This paper speaks of a “surface roughness” that develops on the tin side of float glass and reports “It can be seen that the overall tin side surface roughness average is indeed rougher on average than the air side”. The conclusion reads: “Statistically significant differences were found between the tin and air side surface roughness values for both untreated and acid treated, with the tin side being significantly rougher than the air side.”

Is there a definite link between the rough tin side of some glass surfaces and surface scratching? Does post production heat treatment of glass exacerbate the roughness of some glass surfaces? These questions will be closely examined as you are about to see.

Armed with this knowledge, questions and the collection of scratched glass samples, the IWCA has embarked on the first of its kind scientific research during the summer of 2016. Dr. Paul Duffer has led the way for the IWCA to participate in a special research program at the world class Department of Materials Science and Engineering at Pennsylvania State University. Professor Seong Kim, phd  is dedicated to materials science and has much experience with glass surface studies. He will oversee the IWCA research of scratched glass at Penn State.

The IWCA is dedicated to helping window cleaners better understand the glass surfaces that window cleaners work on daily.  Armed with knowledge as an industry we can develop cleaning methods and practices that will assist us in maintaining the integrity and beauty of glass, reduce possible damage, and adequately protect ourselves should aggressive cleaning techniques and restoration become necessary on a job site.

Please, stay tuned.

Paul West

IWCA Glass Committee Chair

kohalapaul@gmail.com

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Know Your Glass !!!

The focus of this post is just glass.  I am not talking about coatings of any kind.  Glass itself (even when it is perfectly clean without any mineral deposits) can have different surfaces. Over the years I have found that razor blades will either slide across a surface with incredible ease, or drag like you were moving across a hard wooden surface.  Then there is anything in between.  So I have got into the habit of first listening to see if the surface is defective tempered glass.  Henceforth I am NOT going to use the term Fabrication Debris.  Cuz I simply don't know if this is indeed NOT a lie.  Fabricated by very smart minds over many years.  With the best of intentions, and a very noble agenda.  One reason is, because believe it or not, I have also come across very rough annealed glass that did produce scratches.  Which were only visible in the direct sunlight at just the right angle. These did come out with a light polish using cerium oxide slow.  I have also developed the habit of feeling clean dry surfaces with a dry fingertip.  Another favorite tool has been a simple penny. Lightly dragging it across a clean dry surface will produce a sound.  It will even drag at certain points revealing the glass has patchy areas of roughness. Next I might use pure water on a clean paper towel and wet the entire window.  First I will clean the window and wipe the edges.  This will show up the "chemistry" of the surface.  If there are any invisible chemical contaminants present this will show them up. A much more definitive test using water is to cold steam the surface so that you create microdroplets or a fog.  If you look at any fogged glass surface with a 30 power hand held lighted microscope you will see the microdroplets. These will form a pattern on the glass showing very precisely how "clean" it is.

I was talking to a fellow Window Cleaner a month ago who works in my area and made the point that not all glass is the same.  Then before I even started to explain myself he said absolutely!  He has been doing this work for 10 to 15 years and has experienced firsthand exactly what I was referring to. I know we all have talked about the "old" glass.  It is usually very hydrophobic.  No sealants.  Feels super smooth to the touch.  Razor blades just glide across it with extreme ease.  I mean it is just a beautiful surface.  One hundred years later! Now how is it that brand new glass is coming out so different? Another interesting point about tempered glass.  We are always talking about defective surfaces regarding this glass.  But it is possible to find tempered surfaces that are as I put it really "tight"!  Super smooth to the fingertip or the razors edge.  I can ask the same exact question regarding these wonderful surfaces as I do regarding the wonderfully smooth surfaces of some very old glass;...WHY!

Obviously something is afoot here that wasn't so much a hundred years ago.  Also there is something going on in the factories today that either no one knows about, or are very reluctant to let us in on.  I do believe that whatever it is we can figure it out.  This is a material world.  Not talking about mad Donna here.  We have a good understanding of chemistry.  We know about physics.  We can "see" individual atoms and watch as they blink on and off.  We have transmitting electron microscopes to show us nano surfaces using electron waves.  So I propose this.  I do believe Paul Duffer, Paul West, and the IWCA will indeed get to the bottom of it all in time.  Waiting for the end of summer people.  There are several basic reasons why glass surfaces today and yesterday can be very different from one another.  Also, these reasons can be explained using chemistry and physics.  So while I certainly don't have your bux, knowledge, or contacts, I will just sit here, wait, watch, and write.  HAVE AT IT GUYS!!!

Written by Henry Grover Jr.
henrygroverjr@gmail.com
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Is Fabrication Debris a Lie?

The following is an article I wrote for the WCBO some time ago.  Which is a publication of the Window Cleaning Resource. Chris and Alex Lambrinides have allowed me to write it again here and to make ammendments in light of more recent discoveries and theories.  The research of the two Pauls has also very recently been expanded in a very powerful way.  Which I will be writing about shortly.  But not in this post.  Here is the article I originally wrote for the WCBO including an addendum that was never published anywhere.

The Ghost Particle Amended

After discussing with Paul West the results of the tests performed for their presentation at the last IWCA convention entitled “A Search for the Invisible Intruder”, I couldn’t resist giving this article the title “Ghost Particle”. When Paul West and Paul Duffer (henceforth to be referred to as the two Pauls) embarked on this mission of eminence, I don’t think they had any concept of where it was going to take them. Into a bright light that was going to shine on everyone of us bringing the kind of glory that we certainly wouldn’t run from. Or into a dark cavern of inexplicable horrors. I can now see that it was the latter. No one could have been more surprised then the two Pauls.

Since they quite lucidly explained everything at the convention using exceptionally high quality slides for visual impact and education, any reference to their discoveries here will be simple reiteration. Yet for an intended purpose. That being to refresh our memory of what was discovered and discussed, in order to assist in leading us out of the dark cave. To get there however we will have to continue what was started many years ago. As have the two Pauls. That being namely an in depth study of the physical and possibly chemical mechanisms involved in the issue of scratches on architectural flat glass surfaces. This will bring us the glory that none will want to run from.

All scientific studies begin with a question. This was no different. The question was very simply, “Can we absolutely identify the invisible intruder?”. In other words (these being my own), is it indeed possible to prove beyond question that fabrication debris does become fused to a glass surface during the tempering process? Sufficiently so that when broken away or dislodged with a metal scraper and dragged across the glass surface, that Ghost Particle would create a scratch. They were also in high hopes of being able to very specifically characterize scratches caused by such a particle for easy identification in future field cases. Unfortunately their experiments while shedding light on these questions, did not give them the absolutes they were hoping for. Instead their test results raised more questions. Which I believe must be answered before we can progress in our understanding.

While I do not believe in ghosts, I do believe in what I will call here the Ghost Particle. It is in fact invisible. Or is it? The two Pauls did prove that sand particles (which are very abundant in the field) can be harder than glass. These particles can easily cause scratches on glass. Such as when dragged under a squeegee rubber, steel wool, cloth, or even a metal razor. Glass particles/fabrication debris/microfines can also scratch. A metal stylus can scratch. Along with other different particles and objects that are as hard as or harder than glass. The question again was, is it possible to determine exactly what caused the scratch with a microscope? Was it a metal stylus, a particle of sand, or a glass particle/microfine? Paul West told me that it is only possible to determine whether it was a blunt object or a rather sharp one such as a particle of sand or glass. During the IWCA presentation slides of scratches all caused by hard sharp particles were shown. Everyone was asked if they could tell exactly what caused these scratches. No one was able to offer a definitive conclusion. No one knew. Even the point of indentation (where the scratch begins) showed no apparent difference. In fact the total scratch morphology (point of indentation, track, and finish) gave us no clue as to exactly what sharp particle caused the scratch.

Here is another question. We have always believed that microfine particles released by flat glass when it is scoured and broken, are pushed into and fused to the glass surface during the tempering process. Actually bonded to the glass surface. So the two Pauls set up a few different experiments hoping to duplicate this effect. While they did have limited success, the results were much less than favorable in proving our previous beliefs beyond a question or doubt. What they did reveal were some very interesting results. Which in my opinion, will force us to reconsider/rethink and develop more powerful analytical techniques. What we absolutely need is a full color video showing the face of our Ghost Particle wearing a sneer. But with the high tech analytical tools of this century, I don’t see that as being very difficult. Just expensive.

Simply put, when they did their tests they were not able to permanently fuse glass particles to the surface. They used different sized particles of glass and sand. These could be pushed into the glass, but would not bond or fuse once the glass cooled. Every particle was quite easily removed. When glass is heated in the tempering process the surface becomes rather soft. And so as has been stated they were able to impinge glass and sand particles into it. However both the glass and sand particles just ‘popped out’. Most times they just blew away. According to Paul West it was very difficult to get sand or glass particles to stick to glass. Even when the particles were sandwiched between two pieces of glass and put through the tempering oven, as much as 95% of the particles could be easily brushed off.

What is truly fascinating about these results is that they seem to run contrary to my own personal experience. In the last 33 years of cleaning windows I have uncovered many window glass surfaces that seemed to have very small hard particles permanently embedded. When I scraped I could hear that tell tale sound. Then when I soaped, squeegeed, soaped again with clean water, and scraped again;...I could still hear the same sound. The Ghost Particle was seemingly still there. It was also seemingly embedded in the glass surface. Further, I ended up creating scratches when I scraped these windows. At times the scratches could only be seen in the direct sun because they were so small. Even microscopic. But they showed every pass of the razor.

I concluded that I was dealing with embedded particles because of my experience and what we as window cleaners have believed for many years. Which still might be the absolute truth.  However it is good to consider something at this juncture. That sound is not necessarily proof of a particle. We might be dealing with a collection of depressions with microscopic chips removed, or indentation fractures, or something else completely unknown. The Ghost Particle might not even be a particle at all. I still do believe nonetheless that it wears a sneer. I also believe that the only real absolute we currently own is the fact that all surfaces are not created equal.

Here is one very interesting experience I would like to relate. I was called out to a new commercial building. There were many very noticeable heavy scratches on the glass. The windows were so bad I figured I couldn’t do any more damage. But I tried. With the permission of the contractor/builder I soaped up the window and tried real hard to create more scratches with ‘my’ razor.  I ran it in a different direction than the existing scratches so I could easily tell the difference between my scratches and those already there. Yes I could hear that characteristic sound like scraping sandpaper. The surface was seemingly loaded with very hard embedded particles. But I just could not create scratches. Why? To this day I don’t know.  All I can do is guess. One thing is sure however.  I definitely saved one poor window cleaner.  If that isn’t twisted I don’t know what is!

I am sure we can locate and expose the Ghost Particle. Even if it isn’t a particle at all. We need to first find a window that is easy to scratch with a blade. Or any other tool of choice. Create scratches with a unique pattern. Then put a microscope right on it. We might need to remove the window from the sash and bring it into a lab. But either way, we need to implement much more advanced analytical techniques in order to more accurately identify the true nature of this problem/condition. We need to continue this study which we began many years ago. Lets work along with the two Pauls on this quest of eminence. Out of the cave and into the light. 

I have also proven just the opposite of this test.  By running the razor in the opposite direction I did indeed create more scratches.  So this defective tempered surface did produce scratches with the use of a razor.  The apparent FD was very heavy.  The resulting scratches were rather deep and very easy to see.  I have also produced very light scratches on tempered glass.  Further;... I have even produced very fine scratches on annealed glass.  This is absolute heresy!  Such that could never be forgiven.  I am sure the masses will dam me to eternal pits of molten tin for writing this!  But I was told by Paul West today that he has actually obtained a sample of just this.  I would like you to consider some interesting questions.

First have you ever wondered why FD is evenly spread across the entire window?  Shouldn't it be patchy?  It is also not just evenly spread but is either very fine, very course, or anything in between.  But it is never mixed.  As if all the particles were all the same exact size.  "Dirt" is made up of many different sized particles.  Also.  If the same exact process is used for scouring and breaking to size all sheets of glass before tempering, wouldn't these microfines be the same exact size in every situation?  This would mean that all of the scratches produced on every window should be the same.  But they are not.  As I have explained here some are very deep, and others are microscopic resulting in what looks like streaks.

In my last post "Stop Scratching Glass" I used the term Fabrication Debris or FD. We have been taught that this is an unquestionable truth.  I used the term for lack of another.  In our industry there is no other term.  But I believe there should be.  Consider that there might be no FD.  Consider that our understanding of this entire issue could be completely wrong. Not that glass surfaces are not many times defective.  Why;... they are getting worse with every passing day.  But exactly what is happening?  I really believe that even the glass industry doesn't know the answers.  So again I have to say, lets support the two Pauls on this quest of eminence. Out of the cave and into the light.

The next post I write will shed light on this issue/topic, and discuss a research project that will run for the next three months until the end of the summer of 2016.  You will not want to miss any of these posts.

Written by Henry Grover Jr.
henrygroverjr@gmail.com

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Stop Scratching Glass!

I know I am going to get some negative feedback from this post. But I really feel it needs to be written.  There are too many innocent Window Cleaners who have fallen victim to the indifferent attitude of glass manufacturers.  Tempered glass surfaces are almost always defective these days.  The tempering fabricators simply don't care cuz the defects cannot be seen.  It is only the Window Cleaners that end up suffering the repercussions of such poor surfaces.  And what are we to them? Pimples on the butt of a bug on someones butt.  Tempered glass will likely get worse.  So we need to be prepared with knowledge.  And pass this knowledge to everyone we can. Especially General Contractors.  We might never win the war. But we can win a few wars along the way if we can turn some tempered glass BACK to the factories.  For this to happen we need to start testing tempered glass BEFORE it is installed.  To accomplish this we MUST educate, educate, educate.  Lets start with our own companies.

First we need to know that all fabrication debris issues are not the same.  The sound alone will tell you that.  Sometimes when you use a metal razor on tempered glass it wants to drag.  The glass is not smooth.  No scratches can be seen however.  But when you look at the window in the bright sunlight, at just the right angle you will see waves of zillions of almost microscopic scratches. This condition can bring on a lawsuit.  Or.  The scratches might be very light, easily seen, and cover the entire plate.  Other times the scratches can be very light but not great in number.  Then too they might be rather heavy and deep. Covering the entire plate.  They could also be deep but very few in number.  Also there could be anything in between what I have described here.  The sound of fabrication debris when scraped is always different if the scratch ID pattern is different. It is difficult to know when we are working on defective tempered glass most times because the sound is different.  It is also true that many times larger Window Cleaning companies do not have the advantage of using employees that are educated well enough regarding defective tempered glass.

Another misunderstanding I believe has to do with the fact that metal razor blades are NOT the only tool that will dislodge the fabrication debris which is what leaves the scratches.  I have seen scratches caused by Fab Debris moved by 0000 steel wool, plastic scrapers, and other tools and processes.  So many Window Cleaners believe that if they are NOT using razor blades they are safe.  This is simply NOT true.  Again this fact brings us back to what I believe is the true reason for scratched glass.  That being defective surfaces and fabrication debris on tempered glass.

I used to believe that a blind window cleaner had a serious handicap.  Most of you would probably agree with me.  Now I also believe that a deaf Window Cleaner is seriously handicapped.  We must train our ears, and our fingertips. Thank you Chris and Alex Lambrinides for this video.

I know from my 35 years cleaning windows that I am relatively safe when working on tempered glass.  Although I have made mistakes from poor judgement.  As tempered glass becomes more problematic the challenge of cleaning it will become greater.  And the burden will likely always be on the Window Cleaner.  In my opinion.

So.  I am first of all in favor of the waiver.  I am also in favor of self education.  Also educating every employee in the company. Also educating all of our customers and potential customers. Especially General Contractors and anyone who sells or installs windows.  I am very much in favor of looking for alternatives to the use of anything that could potentially remove and drag FB creating scratches.  Such alternatives might include composition abrasives with a hardness much less then glass.  Or certain very powerful organic solvents.  Or special chemicals, maybe acids that will safely remove concrete and or stucco. These alternatives are one thing I am working on as I research commercial products and develop my own transformer products.  My findings will be reported on in my e-newsletter the Product Development Review.  All chemicals, ingredients, formulas, and product names, and addresses will be given. Along with regular email updates/reports throughout the month.  The PDR is available for 35 dollars per monthly issue. Just send me an email.  And I will send the PDF by email attachment.  Then a PayPal bill in another email.  The August issue is entitled Orange Power.  It is focused on naturally occurring green organic solvents.

Written by Henry Grover Jr.
henrygroverjr@gmail.com

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