If you want to learn exactly what mineral acids are go here. Mineral Acids Wikipedia You will learn exactly what a mineral acid is and what are some of the strongest ones. As window cleaners we have used certain ones like hydrochloric, phosphoric, hydrofluoric, nitric, and sulfuric. These are five of the strongest. We also have products intended to remove mineral deposits (hard water spots) that are based on some of these very powerful acids. They are all dangerous. They can blind you, burn and strip your skin from your hands, and do extreme harm to your lungs. Just read the MSDS (SDS) for any one of them. Do a search by typing in the acid along with MSDS or SDS. What you can't easily learn is which ones will do little to no harm to glass surfaces. Which ones will have no effect at removing hard water spots from glass. Which ones can potentially do very bad damage to glass surfaces under different circumstances. And which ones have been blended into commercial products for removing hard water spots from window glass. Because they have not been included under the ingredients section of the MSDS for the commercial product in question.
Now none of us want to chance doing harm to our own or another persons body. So we would want to stay away from powerful acids like these for this reason alone. Regarding the potential harm that an acid or an alkali (base) can have on glass however, this is something that many window cleaners wonder about. The reasoning they follow is rather simple. If I can protect myself from any physical harm of a certain chemical or product, and know in advance that there is no chance that it will destroy the windows I am attempting to restore, then why not use it? I would say of course the choice would be yours. But you can absolutely know this. That the results you might get from the same exact product, can be different from one window to the next. One the same building, and even on the same plate of glass!
On this last note we must ask another question. How can we know that the chemical or product absolutely could not and would not do any damage to the glass surface? Is it even possible to get close to an answer?
When I started down this road decades ago I got out the books and started doing research. I asked different manufacturers. And quickly discovered there were no absolute answers. So I started buying acids, products, and new glass test plates from the local glass shop. Then I started doing my own experiments. I let my imagination run. What I learned from these flights was amazing! Things that no other window cleaner or book could tell me. Then I started traveling to buildings that had been chemically wasted. I would like to tell you some great stories some day! Went home and was able to duplicate the damage using the same products and chemicals. It was fascinating.
The bottom line is that I was able to develop many different tests and standards that could plainly tell me in advance exactly which products and chemicals were most likely "safe" and which were not. With these tests and standards I didn't need any other knowledge from any source. The tests served as my own personal compass.
With this knowledge you will never have to ask anyone any questions about any new product. YOU become the authority. That is what I am now working on with IGSA Tests and Standards. I am working on developing an open association of window cleaning consultants within the window cleaning industry worldwide. IGSA stands for International Glass Smart Association. And Smart stands for Surface Maintenance And Restoration Technology. You will find the very first of these tests here. If you have any further questions please send me an email.
TESTING MINERAL ACIDS FOR GLASS SURFACE SAFETY
There are five basic tests for this. From which I am sure others will follow.
#1 The Ripple Test;...Tools are necessary for doing anything. Coupled with a sharp mind they can be extremely effective! There are certain mineral acids like HF that are very effective at eating through and sloughing off a layer of glass. I call this the ripple effect. Anything such as a hard water spot will accent the power of the acid and speed up this effect. It begins by drawing a single line on a clean glass plate with a paint marker. Let it dry in a minute. Then wet the glass with the chemical in quest for a few minutes, and rub away the paint. Soap and squeegee then look at the surface in the direct light. I like using a mirror and bring it outside in the direct sun. You will be able to see where the paint line was. It will show up as a transparent ripple.
Another way to look for the ripple is to put a small 4 X 4 inch piece of clean glass half way down in a cup of the chemical in question. Leave it there for a few minutes. Then remove it, clean it, and look for a ripple at the air/liquid interface. If there your chemical created a stage four dynamic etch. The ripple can be presented in court.
#2 The Scratch Test;...This also comes with some rather simple tools. Not leaving out a sharp mind. Take a clean mirror. 6 X 6 inches is good. Create a patch of scratches in the middle. Then apply the chemical to ONLY one half of the scratches. You can protect one half with some Duct tape if you chose. Apply the chemical in question to one half of the scratch patch. A minute is plenty of time. Now rinse off your chemical in a stream of water. Dry the mirror. Take it into a dark bathroom. Look at the patch with a flashlight by looking down the beam of light. Certain acids will cause stage two statin etching of the scratches leaving behind white crystals in the trough of each scratch. So the scratch patch becomes forty times more accentuated. But ONLY the side that made contact with the acid or product in question.
#3 The Vapor Test;...Take a plastic bowl and put your chemical in question in the bowl after heating it. Just enough to create a vapor on a plate of glass. A cool or room temperature plate will help the vapor to form. Flip the plate over if a mirror so the glass side is facing the chemical. Or just put the glass down on top off the bowl. If an etch occurs this will show up as a cloudy white affect.
#4 The Drag Test;...Take a plate of glass and clean it well. Then wipe on and rub in your chemical in question for about a minute. You can tape off one side if you want to be certain there is no contamination. Next clean and dry. Then lightly run a dry fingertip across the entire dry surface. If any etching has occurred the side that made contact with your chemical will be much more rough if etching has resulted.
#5 The Water Microdrop Test;...Take a new plate of glass/mirror and clean it well. Tape off half and apply your chemical in question to only half the plate for about a minute. Clean and dry with no contamination. Next apply pure water to the entire surface (both sides). If etching has occurred the water should fully sheet over the side that made contact with your chemical. The surface has become hydrophylic. This effect will dramatically also change the size of microdrops caused by a foggy film. The drops will be MUCH smaller on the side that came into contact with the chemical. Your tools must be more "scientific" however. I suggest at this time that you purchase for around 60 to a 100 dollar hand held lighted 40X magnification microscope. It should also use a free app so you can send videos and pictures to your smart phone. If you do this please post them to the WCR Community Forum. I would love to see them and have others see too!
Now you have everything that I have! There is no reason why you should be using destructive acids in your work that could potentially cause the loss of your business. And there is absolutely no reason why anyone should get away with telling you an untruth.
If you want to perform any of these tests you know how to do it. If however you would like me to personally perform any of them for any reason on any surface just let me know. They are also very effective on low e surfaces too. But not all. Simply because most low e surfaces have a titanium dioxide coating. Which is a radically different surface than glass. Check out my GSP Logo at the top of this blog. It shows the different elements/atoms that make up all soda lime window glass.
If you would like to know more about the IGSA Tests just send me a question at henrygrover222@gmail.com
Written by Henry Grover Jr.
