What scratches and when?
This is usually a total crap shoot. A throw of the dice. We might win or we might lose. Did you know there is a way to dramatically increase the odds in our favor? It involves a very simple test that almost no window cleaner has ever performed. Let me explain.
I have developed many very simple tests over the years that anyone can do. This one involves the use of a one by one foot square mirror. I choose mirror plate because it is very easy to get. Also mirror shows up the slightest blemish. At times I will take the "test plate" into a totally dark room and shine a flashlight at the surface at a 45 degree angle. Then look straight down the beam of light. This shows up every imperfection.
Tools, compounds, and machines.
So I take a brand new mirror and polish the entire surface with a cerium oxide (optical quality). It should look perfectly fine without any imperfections. The best way to do this is with a rectangular piece of soft felt glued to the based of a random oscillating buffer of about 10,000 opms. That is oscillations per minute.
You will know that you have set up the surface correctly because when you rinse it under the tap pure water it will sheet evenly over the entire plate. It will be so hydrophylic (water loving) that it will appear to be dry. Now squeegee off the water so it is dry. You will notice that the surface is now quite rough if you pass a dry fingertip across it.
What surfaces are way easy to scratch?
Rough surfaces are extremely easy to scratch. Items that would hardly ever scratch a smooth plate of glass will absolutely scratch a rough surface. This test plate is great for testing metal wool, synthetic wool, and many other things. While it is not absolutely fool proof, it will help out tremendously at revealing what items are very prone to scratching.
Adding Glass Etchants to the Test.
Another additional feature of this test involves the use of hydrofluoric or sulfuric acid. Sulfuric is easy to get from an auto parts store because it is battery acid. So very dangerous. Hydrofluoric can be obtained by purchasing so called glass restoration products based on a little over 1% HF. One product called Crystal Clear 550 has this chemical. Again it is a very dangerous chemical so be very careful I have posted some very educational videos in this blog. You can search the blog with the search bar. When testing I will try to scratch and area. Then treat only half that area with either acid. HF works best. Take the test plate into a very dark room and look at the area that was tested with a bright flashlight. The acid will have magnified any blemishes 25 times over making them very visible. You will also be able to compare all three surfaces. The roughened surface untouched. The roughened surface tested with the product in question. Also the roughened surface tested with both the product in question and the acid applied afterward to magnify and blemishes.
Minimizing the Likelihood of a Lawsuit.
If you know what most likely is going to scratch and what most likely is not going to scratch you are most like going to be able to avert any lawsuits. This is indeed our goal as many times we are faced with removing various things such as construction debris but do not want to do damage to the surface. Especially if it is brand new glass. Being an older house no one seems to care that much. But brand new homes always come under the responsibility of whoever is the very first one to clean them.
Written by Henry Grover Jr.
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