We are The Stain Removal Scientists

Marc Tanner told me the other day that, "we are the scientists here"!  I have been writing about looking at the grinding and polishing technology of the optics industry.  My idea was to use this same technology in restoring window glass surfaces. Whether we are removing hard water stains or scratches it should be possible to accomplish this more efficiently by researching a field that has been practicing this for many decades.  But after another forty five minute chat with Marc I realized this is not a perfect plan.  In fact we are going to have to figure it out ourselves. Here is why.

Every glass surface is different.  It is different especially in hardness.  Different in compression strength.  Different in chemistry.  So the tools we use to grind and polish all of these different surfaces must be different also.  Then we have the deposits.  These are also different.  Each has a different chemistry.  The amount of damage each has done to the glass surface is different too.  Some mineral deposits will literally eat deep into the glass.  Some are rather light and just lie on top. Such are easy to remove with a light cerium polish.  But heavier deposits must be first removed with a grinding process.  The product of choice by the gurus within our midst is based on silicon carbide or SiC. Even some of the commercial stain removal systems for sale use this abrasive.  There are however complications to this step.

First the grinding step MUST be done without leaving any "waves" in the surface.  Cuz it doesn't matter whether you are removing scratches or heavy stains, you will need to remove glass.  When you do this wavy glass can result.  Which is very visible from twenty to a hundred feet away.  Next the product used cannot leave swirls of scratches.  I definitely have not given up my idea of using diamonds.  Hey.  I made ten grand one time using diamond compound to remove silicate stains. By hand with Bounty paper towels.  NOT with a machine. Machines tend to leave swirl marks.  Whether the product of choice is diamond or silicon carbide.  SO.  This brings me to the next complication.  When removing heavy stains by a silicon carbide based grinding process we must use a product that will leave the most smooth surface possible.  The reason being is so that the final polishing step using cerium oxide can be accomplished as quickly and efficiently as possible.  

Obtaining a quality surface by grinding is not an easy one. There are so many different silicon carbide based products out there.  The gurus use a coated SiC paper.  Yet finding the correct paper is not easy if not virtually impossible.  Just look at the SiC particle.  There are well over two hundred different polytypes of SiC. These are of several different shapes.  They also have other different properties.  Then there is the resin holding the particles to the paper.  Sometimes the wrong resin will yield completely different results.  Same particle, different coating resin, different results.  If you ask the manufacturer about the chemistry of the resin you will not get a good answer. This is considered an industry secret.  That is how important the resin is.

Polishing glass with cerium oxide is also a rather complicated process.  Even if you are just removing light stains.  Not to mention removing a SiC haze from grinding.  It is first critically important to ensure that the glass is as clean as possible.  No amount of oil should be present.  That is because cerium works by both a physical and a chemical process.  The chemical process uses water.  Oil repels water.  Some other factors to consider are temperature, pH of the solution, and the concentration of cerium oxide in the water.  It is also important to use the correct pad.  Also care should be taken to keep the cerium from building up one the pad otherwise the pad will just skim over the surface and not "cut".  The RPMs of the pad are critical to maintaining good contact and keeping the temperature down to around eighty degrees.  A hand held laser temperature gauge is real handy to constantly monitor the surface.  Here is the video demonstrating my Wobble Wheel and the use of a slow release cerium pad.

Next couple all of this with the talent factor.  I liken this to using a squeegee.  I have trained many people over the last thirty five years.  Most take months to "get it".  But once in awhile someone will just pick it up and go at it.  They have a natural talent.  The same is true for grinding and polishing flat glass surfaces.

When you blend talent and science the result is inexplicable. But that's where it's at.  I completely agree with Marc that we are the scientists here.  So I will continue to focus on the science. As we continue to make advancement you will learn about it here on this blog.

Written by Henry Grover Jr.
henrygroverjr@gmail.com

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