Testing IGs For Negative Pressure Deflection

I finished a job today that exhibited very pronounced negative pressure deflection.  Especially the very skinny (about 14 inches wide) insulating glass units were very low on argon.  And yes, these were Anderson windows.  All of them.  Some were worse than others.  But all of the IGs demonstrated NPD.  If you want to know more about this problem check out my post on defective argon units.  Then go to the article referenced and read it.

The method for testing is very simple.  Just take your trusty six inch razor, soap up the window with some good sudz, then run the razor vertically straight up.  If there is even a slight problem with NPD the razor will miss some of the middle.  The more soap left in the middle of the swath the greater the effect and the more problematic the window.  Today I observed a virtual 'no contact' in the middle.  Just the two tips of the razor made contact!  Of course when I turned the razor and ran it across the window horizontally from left to right, it left no soap at all.

So there you have it.  It really doesn't need to get any more high tech than this.  If you show your customer this and relate the stories of those people who experienced the implosions, you will get attention.  Cuz you see.  We don't just clean windows.  We inspect them too.

Written by Henry Grover Jr

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Hydrophobic/Hydrophylic Balance

If you were to wet a brand new clean window glass surface with pure water you will notice that the surface is not equally funtionalized.  The water will sheet in places of the same plate and bead up in others.  This is not necessarily because there are contaminants unevenly covering different areas of the window.  It is likely because the physical integrity of the near surface is different.  The more 'rough' a surface is the more it will soak up and hold onto water.  Water will form larger beads when it condenses as fog on the surface too.  So the more rough a surface is the more hydrophylic it is.  The opposite is also true.  The more smooth the surface the more hydrophobic it is.  Condensed water or fog will also form smaller beads when looked at through a thirty power handheld lighted microscope.  You can prove this by polishing one side of a mirror plate with a cerium powder of five microns particle size, and then the other side with an aluminum oxide of 100 to 400 nanometers.  You will be able to feel the difference with your fingertip.  In both cases the chemistry of the surface is exactly the same.  The only difference is how smooth each side is.  The side polished with the submicron/nanometer scale aluminum oxide will be much more smooth than the opposite side polished with the cerium oxide of five microns.

Now.  What does this mean to a window cleaner using a water fed pole?  Simply that the results will be different from one window to the next.  Also.  When we choose an inline chemical to functionalize the surface as we clean, it would be best to choose one that will effect the correct balance between hydrophylic and hydrophobic.  This is because of two reasons.  First we do want to functionalize the surface equally across every square inch.  Second water will sheet best from a balanced surface.  If the surface were super hydrophylic it likely wouldn't sheet at all, but would rather cling to the window leaving a light film.  Also the very best hydrophobic surface is not superhydrophobic so little beads of water will form.  It is therefore more time consuming when cleaning an ordinary hydrophobic surface with a water fed pole.  The very best functionalized surface for the WFP user will be both hydrophobic and hydrophylic.  This balance can actually be measured by measuring the contact angle of a drop of pure water.  Also.  The eveness of the 'new' surface can be analyzed by fogging the entire window.  You will be able to easily see at a glance the pattern. And to reiterate the more hydrophylic surface will have the smaller water drop when the window is fogged.  By looking at the size of the water drop on the new surface under a microscope it is possible to quantify different chemical treatments to find the one that works the best.  Or at least to be able to label them from most hydrophylic to the least.  Then to choose the one that we prefer.  Almost like someone chooses a soap/cleaner depending on the level of suds action, and glide.

Written by Henry Grover Jr

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Creating Alkaline Water Via Resin Exchange Chemistry

Once you have reduced the TDS down to 0, and you now have totally pure water;...where do you go from there?  Why not use a resin exchange medium to alter the hydronium/hydroxide ion balance to raise the pH to a figure higher than neutral? Window Cleaners have already experienced fascinating results cleaning glass with ultrapure water with a very high pH.  Why? Because most of what we are removing from window surfaces are acidic.  Alkaline solutions will neutralize such contaminants.  This is how surfaces are cleaned.  Mineral deposits (hard water spots) are composed mostly of silicates. Which are alkaline.  That is why manufacturers have created products based on acids to remove them.  So.  Why not use another exchange tank to remove the hydronium ions from your ultrapure water making it a naturally powerful cleaner? What do you think of this?

Written by Henry Grover Jr

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Removing Mineral Deposits With Diamond

Diamond is the hardest substance on earth.  Well almost.  The water molecule might be even harder.  But for practical purposes it's hard enough.  And despite the extreme value of natural diamond gemstones, it has a greater value as a synthetic material used by machinists.  It might even have an unsuspected value to us.  For quickly and efficiently removing hard water deposits from window glass.

I will never forget my 'house on the hill' down in Amherst.  The windows had been damaged by a solution of sodium carbonate and sodium metasilicate.  A white haze which couldn't be removed with anything.  Except diamond.  I used a 5 micron compound in a syringe with Bounty paper towels.  No other compound worked.  Not even the acid based 'wonder products'.  What I personally find fascinating is the fact that diamond compounds don't shine like this in all cases.  Most of the time they perform equally as well as a compound based on a cerium or even a plain optical silica around five microns average particle size.

Another time I was working on sprinkler stains which covered dark glass.  No compound worked.  Even diamond compound with or without machines would touch these stains.  But a 'water wheel' based on a system of hardplastic nubs which were loaded with 5 micron diamond particles knocked it off in very little time.  All I used was water.  The only problem was the wheel left millions of very fine barely noticeable scratches.  Such were unacceptable.  I never continued working on this technology until now.

The technology of superpolishing glass with diamond loaded plastic is quite common.  There are many products out there.  The trick is finding the exact one that will do the job and not leave any scratches.  Then creating the wheel that will work best with this material.  This is one of the projects that I am currently working on.


Written by Henry Grover Jr

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Cleaning Glass with Sodium Hydroxide

Has anyone ever worked with oven cleaner to remove staining from aluminum screens?  It works really well!  Sodium hydroxide has a voracious hunger for certain metals.  It will even eat up soda lime glass in minutes.  At the right temperature and concentration.  Did you also know that restaurants use a product based on this chem to clean the grease off their grills?  Did you know too that it is used at farms to completely liquify dead animals?  Also it is used at 100% concentration in the form of crystals to eat up hair in household drains.  Furthermore it is used in food products. We eat it!  So why not clean with it?

OK.  So I went out and picked up the 100% dry crystals at the hardware store.  It cost me about fifteen bux for sixteen ounces. I had a pizza/sub shop to clean that I was called back into after at least four years.  Use your imagination.  It was bad.  My cleaner was worse.  It ate right through everything.  There were  a few windows that hadn't been touched at all for several years. They looked like they had a dark solar tint on them.  So I needed to scrub a little with 0000 steel wool.  But when I was done that glass was crystal clear.  Of course my skin was black and dried out.  Next time I will use gloves.  Infact let me say this.  Sodium hydroxide will really burn your skin bad.  And you should never let even the smallest amount in your eyes.  So gloves and goggles probably would be best.

In practice I discovered that rather than a teaspoon per gallon I could get away with ONLY  1/8th of a teaspoon per gallon;...or less!  I didn't say a tablespoon.  I said a teaspoon!  And this is for routine cleaning at a pizza/sub shop.  Restoration grease stripping would require more.  Remember to always used rubber gloves too.  Keep your hands dry.  As an interesting additional thought I was wondering about the use of plastic compositional abrasives in connection with more powerful alkaline cleaning chems such as sodium or even potassium hydroxide.  I have written an entire newsletter (The Vision Glass Detailer) on putting together a specialty cleaning formula based on an alkali, a nano colloidal silica, and a hydrophobic silane sealer.  This cleans and seals in one step.  But it is just one variation of the idea of coupling different elements to get superior results.  The idea here would be to add cushioned plastic compositionals to a flat wand to wet and scrub the glass simultaneously.  Do you hear me on this one manufacturers?  I know you have already tried different things.  But you have been off regarding the size of the particles or 'strands' used.

So here are the questions.  Since the technical literature that I have read indicate quite plainly that very strong alkali solutions will etch glass, will a much lighter solution of sodium hydroxide also cause etching?  My thoughts are that it will.  In fact it should cause complete dissolution of the glass surface.  I mean;...check out this video.  http://www.youtube.com/watch?v=nmktRTHL1NA  We need to know if this could be visible or not.  Therefor I suggest performing the two different tests I have developed here for acids.  It is true that water itself is quite capable of etching glass.  But under conditions other than routine cleaning.  So when testing cleaning/restoration solutions of sodium hydroxide we should stay with the concentrations used in each.  It is also obvious if we use much higher concentrations at much higher temperatures, than we absolutely will etch glass. 

When I tested the different acids used in so called commercial restoration products (none will be mentioned by brand name in this blog), I tested them at the concentration that is suggested they be used at.  I also tested them at the temperature they would be routinely used at.  Time is also a condition.  Certain acids will show etching in as little as thirty seconds.  To create visible distortions of the surface I did wait thirty minutes.  However there are times in practice when this amount of time could be a factor.  Such as when the solution puddles at the bottom of the window and remains there since it might be an overcast cool day.  It is also true that the glass might be dark and very hot from the sun.  Both the composition of the glass and the temperature could easily contribute to the visual effects of such acids (etchants).

There are other questions that should be answered.  Such as the problem of the yellowing of white vinyl window frames and vinyl siding.  Oven cleaner will yellow out white vinyl in seconds.  Especially on a hot day.  It is based on a 4% solution.  At what concentration is a sodium hydroxide routine cleaning solution safe to use around white vinyl?  To answer this I might heat up some water to about 180 degrees F.  Put in a certain amount of crystals.  Mix it up.  Then do the dip.  Dunk a strip of white vinyl used on window frames.  Leave it in there for at least five minutes.  Remove and inspect in bright sunlight.

So.  I certainly don't write for the ASTM.  None of us are scientists.  We are Window Cleaners.  Nonetheless I do believe we should become accustomed to testing the different products and chemicals we use routinely in our work.  Since we are professionals!

Written by Henry Grover Jr

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