Testing Sealants Against Alkali Attack

If you charge someone tens of thousands of dollars to remove hard water spots/stains from their windows you better be able to guarantee your work.  Because no one is going to want to spend even close to that kind of money every six months just to have clean windows.  We on the other hand don't want to spend a great amount of time just to keep them clean.  The best way to do this is to seal the glass surface.  But seal it with a product that will stand up to the ravages of the high pH of hard water drops.  We want the absolute best.  But how do we know which product IS the best!

pH resistance is not determined by whether the sealant is hydrophobic or hydrophylic.  It is true however that a water drop will attain its highest pH during the last few seconds before it completely evaporates.  This is because the water in the drop attains the greatest concentration of mineral salts around the outer edge of the water drop.  Just before the drop poofs away it becomes a water ring.  This is the reason the water spot is more of a spot ring.  If you study these pictures of different water spots you will see clearly what I mean.  The middle is a dry basin with very little mineral deposits.  When polishing the windows the most difficult part of the spot to remove is where the greatest concentration of minerals are.  That being the outer edge of the spot rings.  So a hydrophobic surface will encourage the formation of water spots.  Whereas a hydrophylic sealant will not.  It will cause the minerals to spread out evenly making it more easy to remove.  However if the hydrophobic sealant is much more resistant to pH attack then that would be the better sealant to use.  But if the hydrophylic sealant is even just close to being as resistant to pH attack, then that would be the better choice.

The best way to find the best sealant/product whether it be hydrophobic or hydrophylic is to put several of them to the test on the same plate of glass over the same amount of time.  So clear the window with a polishing system.  The bare glass should sheet over.  Glass is naturally hydrophylic.  It is only hydrophobic if it is contaminated with hydrocarbon or other hydrophobic residue.  Next tape off a number of squares.  Then apply the different products, one per square.  Wait six months and try to remove the newly formed mineral deposits/spots.  First with an applicator and squeegee.  Then with more aggressive methods such as 0000 steel wool.

Another way to test for the best sealant is to polish a brand new plate of glass.  This will make the glass totally hydrophylic.  It takes about 30 seconds per square foot.

Then seal the entire plate with a hydrophobic sealant.  After this apply a few splotches of fresh concrete.  It only takes a couple days for the concrete to harden.  During this time the pH of the concrete reaches 9 to 9.5.  Which is very high.  It will literally eat right through most sealants.  Next push off the concrete then run tap water over the glass.  If the concrete has eaten through the sealant you will see the water sheet over the glass only where the concrete was.  If not you will have discovered a high quality sealant that is resistant to alkali attack.  Test out the other sealants in the same way.  When you find the best hydrophobic sealant all you need to do is test it against whatever hydrophylic sealant you might have.  To do this just follow the instructions given for the first experiment.  Give it a good six months.  The maintenance cycle will depend on how big the building is.  Also how intense the stains are.  

These tests will give you the ability to offer a guarantee.  You will know exactly how much time it will take to remove the stains, and how much time it will take to keep them off.  The tests will also tell you exactly which sealant you want to use.  Although it still must be factored in I wouldn't care too much about the expense of the polishing compound or the sealant.  The greatest expense will be in the time.  Time is everything to us.  The time will determine the cost.

Written by Henry Grover Jr.

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DIY Self Cleaning Products

Window Cleaning Companies can now get into the technology of applying self cleaning coatings to window glass.  This is fast becoming a specialty line of work that only the Window Cleaner is truly qualified to take on.  It is another service that can substantially increase your bottom line.  The chemistry and technology exists right now.  If you chose to not get involved you will miss out.  Lets check out the technology of making glass dirt resistant and hence "self cleaning".  We will also look at some eye opening videos that demontrate what is now being done.

Self cleaning glass is either hydrophylic or even hydrophobic.  Most of us are familiar with the former which is coated in the factory with a titanium dioxide chemistry.  This type of coating is water loving.  Pure water drops should spread out and not bead up.  The idea is that first there should be no spots if there are no drops.  The rain should hit the glass, spread out, and "drain off".  TiO2 is supposed to also be photocatalytic.  Which means the energy of the Suns UVC transfers to the dirt by means of the TiO2 surface causing the particles to break up and dissolve in the rain.  Then as the rain drains off the glass it carries the dissolved dirt with it.  Self cleaning coatings based on TiO2 are usually applied in the factory by a vacuum sputtering process.  We could not duplicate such a process in the field on old glass.  However there are now DIY products that can be applied in the field.  Check out some of these educational videos.

This product comes from Denmark and is obviously also based on a TiO2 chemistry.  If I were to apply it for testing I would first polish the glass with a cerium or optical silica compound so as to remove all hydrocarbon residue.  Which tend to make glass hydrophobic.  Then I would apply Shine On and wait to see if it really does photocatalytically remove all dirt and hydrocarbons that would cause the surface to become hydrophobic.  This would be a very effective test to see if these coatings really do work.  I would also do a side by side test on the same plate of glass.


The other selfcleaning coating is water hating.  It is designed to purposely cause water to bead up.  This effect is intended to cause the water drops to "roll off" the window when rain hits it.  The more hydrophobic it is the better it works.  The best example in nature of a hydrophobic surface is the lotus leaf.  This is actually a superhydrophobic surface.  The water drops hardly make any contact with the surface.  So much so that a superhydrophobic surface is considered a totally different animal, although the effect is very similar to a hydrophobic surface.  This type of surface is self cleaning in that the water drops actually pick up dirt as they roll down the window.  This acitivity can be easily demonstrated.  I have included a link to a couple videos showing that here.

Although again I should interject the question, does it really work in the field.  I have done things on glass in my basement that I could not duplicate in the field.  So I am always in question of what people create.  Even when a product does work in the field I always ask questions.  Like how well does it work?  Or does it really work better than another product that I can buy off the shelf?  I get it that education is necessary before someone can correctly apply products.  I would never put a squeegee in the hands of a homeowner expecting even adequate results.  But why make out like your product is better than everyone else's and demand a premium price just to get in?  You know pay to pay.

So lets put these different products and coatings to the test.  Then when we know the results we can speak confidently from experience to our customers and they will believe us.  We will believe us.  So lets start by setting up the first experiment.  Because our work as Window Cleaners is absolutely changing my friends.  We are cleaning surfaces that are not glass surfaces anymore.  We also are being given the ability to alter glass surfaces ourselves.  Products are coming onto the market that allow us to transform window glass.  We can make it selfcleaning by adding a tatanium dioxide hydrophylic coating.  Or make it selfcleaning by adding a superhydrophobic coating.

Keep up with this technology by staying in touch through this blog.  To receive every post as it is written just type your address in the box at the top right, "Follow by Email".

Written by Henry Grover Jr.

If you would like a photolink on the right side of this blog just send me an email with your website address.
henrygroverjr@gmail.com

Aquapel;....A Glass Sealant

As I have said before, all glass sealants are definitely NOT created equal.  Some are more resistant to UVC, some will resist scratches, some will last much longer than others, some will resist the high pH of curing concrete, some will stand up to hard water drops so you can just wipe off hard water spots with a dry towel.  So what of Aquapel?  Well as some of you might know this product was developed for auto glass.  As many of the different sealants were.  Lets take a close look at this product.

In the photo above you can see the applicator that contains a long glass tube which is air tight and holds the liquid chemical.  When the two plastic wings are squeezed together the glass tube is broken letting the liquid sealant leak through the felt bottom.  The felt is not very easy to see in this photo.  The product is applied to the glass as shown by wiping it on.  I suggest first cleaning the glass really well with some 0000 steel wool or even a cerium oxide or optical silica compound such as my SKRUB.  You will know that the glass is really clean if pure water sheets over every square inch.  Make sure the glass is totally clean then apply the Aquapel.  Once applied buff it in with a dry paper towel.  Then apply a second coat.  You can scrub with soapy water and squeegee dry as a last clean if you want like you would with Rain X, but you really don't have to.  You will find that Aquapel does not leave a filmy residue like Rain X does.  It kind of pings clear.  Sorry that's the best way I can explain it.  You will have to do it to know what I am talking about.  My guess is that the chemistry is indeed quite different.  This would explain the ping effect and the greater longevity.  Yes Aquapel definitely lasts much longer than Rain X, is more resistant to abrasion, and definitely stands up to the harsh UVC of the sun much better than Rain X.  I have found it on EBay for around two bux per applicator if bought in bulk.  https://www.ebay.com/i/351809325432?chn=ps&dispItem=1  A single applicator will cover about 25 square feet.  I can usually get a full windshield and two side windows done with one applicator.  Now for the initial effect there is no difference between Aquapel and Rain X.  But as the weeks and months wear on you will definitely notice the difference.

The sealants out there are based on siloxanes, silanes, organics, teflon, functionalized  nanoparticles, even diamond like coatings.  They can be purely topical coatings that just set on top.  Or they can react directly with certain molecular groups on the glass.  This type of product will last a much longer time.  Check out this site for information on the chemistry.  http://hydrophobicsam.blogspot.com/2012/03/ 

Written by Henry Grover Jr.

henrygroverjr@gmail.com

Member of the IWCA Glass Committee

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Are You A Glass S.M.A.R.T. Window Cleaner?

First off,... we all need to know that all of our work is surface level.  That stands to reason right?  Well not entirely.  Because what we do on the surface of window glass can dramatically affect the structural strength and integrity of the entire plate and ultimately the entire building.  That is what everyone has been missing.  And that is what the IWCA Glass Committee has just now brought to the table for all of us to see.  So where do we go from here?

We should recognize that we are in fact Glass Surface Maintenance And Restoration Technicians.  As such we should be paying attention to the science that Penn State is bringing to us.  The first step involves recognizing that once the chemistry of the surface has been seriously altered the overall strength of that surface has been diminished.  By altered I mean the sodium atoms have been leached from the surface by water.  Also by diminished I mean now the surface is much more prone to PIFs.  A PIF is a Point Indent Fracture.  Which most every scratch begins with.  This is serious because that is how glass plates are cut when they come off the glass line, and in the shop.  They are scoured or scratched with a diamond stylus.  Then bent;.... and broken in half!

So the first step in our work should be to check out the surface of the windows we are cleaning.  How rough are they?  Do they already have scratches?  Do they have hard water spotting?  Do they have inclusions?  Have they been sealed?  If so by what?  Have they been sealed by a product that is in general resistant to scratches?  Not all sealants are!

The application of a sealant should be the first step on a brand new building.  Especially in a high pollution environment.  Or on a building that we just know is going to promote hard water spots.  Either from the minerals leaching from the exterior facade, or sprinkler heads positioned several feet from the glass.  Remember both we and our customers existing or potential must stop thinking of the service we render as just "window cleaning".  We are Glass Surface Maintenance And Restoration Technicians.  We are G-S.M.A.R.T.

Lets follow the science.  Include it in our educational materials.  And use it in our marketing campaigns.  If possible we should support our industry.  One way to do this is to join with the IWCA and work with the Glass Committee by going out into the field and bringing back to the GC the information they need to do their job.

Written by Henry Grover Jr.

Member of the IWCA Glass Committee

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