I agree with Tony.
If it is a chemical stain aka etched glass. Then no alternative chemical will get the clarity back. One will have use a polisher system. Be it Glass Renu, SRP, Scratch Hog ( i think that’s what its called) etc…
one has to consider if it is cost effective to polish it or have it replaced if the labor exceeds replacement costs.
Chemicals have been on the glass for a long time. The customer thinks I didn’t clean it right. The drip marks from the chemicals are in the glass and it looks like I didn’t remove the liquid from the surface.
You could demonstrate your technique for them on the glass in question. Show them that even a razor isn’t getting any of the stain off and then explain there are 3 options - 1) replace the glass, 2) use a scratch removal system to abrade the stain off the glass at about 1/2 to 2/3rds the cost of replacement, or 3) live w/ the glass the way it is.
Tony is absolutely right. We have shot, and uploaded Restoration Revolution Episode 3 that covers this topic exclusively. I don’t know when Chris and Alex are going to post it up, but check back often because it should be up soon.
In the mean time you can check out a demo video of the etch removal that is in the WCR store on the Scratch Removal page.
As long as the glass is not cracked, you will be able to make it as good as new. I have taken out chemical stains (acid etching), scratches, and even extreme damage. As long as you follow the instructions you will be able to restore the glass to as good as new.
As for chances of destroying the glass, the only way to destroy the glass with the GlassRenu system is to break the glass. As long as you follow the instructions (I will say it again, FOLLOW THE INSTRUCTIONS) you will be able to remove damage without destroying/breaking the glass. In interest of full disclosure, we get about a .02% breakage rate among users but in all cases it stems from customers trying to take short cuts and not following the process as laid out.
I actually was working on some glass this week that has this same problem, previous cleaner used something, probably pool acid on 4 double hungs with bad water staining., two are really bad. I used Safe Restore first, did nothing, then used A-1 with a buffer, no real effect on it. Then, I used CC550, never used it before, but wanted to see what if anything would happen. Nothing. The glass has a haze over it, not fully corner to corner, but generally where the water staining was. I have some of that ABR I think it is, to remove acid etching, and I have Glass Renu. At this point the client knows it probably should be replaced (all of them), but I want to experiment with what I have to see the possibilities, I know Glass Renu will take it off, but am most likely going to try the ABR first. Obviously I have more time in it than I should make, the house is next door and I can do it at will, and like I said…I’m experimenting to see what works and how well.
Well, it actually went pretty good, the two really bad panels now have about 95% clarity. If you look at a certain angle you can see some clear spotting left on one…clear spotting or etching, whichever. I used the ABR and a buffer with a 8" sponge cutting pad. I probably spent about 15 minutes on each. Put it this way, I feel much better about charging her full price., it just helps the overall sale as I did 6 more stain removals with it today, they came out next to perfect. Client is estatic. Process on the other 6 were, Safe Restore, then A-1 with same pad, cleaned both sides, checked, then went back over 2 panels with ABR, that stuff works sweet, I really like it. It’s faster than A-1 and the finish is a lot better when your done, like new glass. Mostly I was concerned about getting the “haze” off the damaged panes, and it did that, they are clear.