just a word of warning for anyone who wants to try Shem’s slurry. i used it today and it etched the glass. i wanted to give it a shot while trying to remove cedar shake roof sealer that some hack roofing company sprayed all over the customer’s windows. i did a small test spot and applied as directed, then cleaned off. there were definitely some very fine scratches after the fact. fortunately it was in an inconspicuous area.
maybe i scrubbed too hard, maybe it was this particular glass. i’m not sure. my guess is that the mild abrasive quality of bar keeper’s friend was the culprit. either way, i highly recommend you do a thorough test of this mix somewhere safe before going for it.
i ended up using oneRestore, which worked great (as always.)
Oh my oh my oh my. One thing I didn’t mention was that I cleaned all the glass prior to using the slurry. That wasn’t planned, it was to be able to see what I was working with once it became apparent the glass was heavily smeared with silicone. Grit on the glass will lead to a bad result. Damn, sorry Caleb.
let me clarify, the glass was clean already. it just had oily sealer residue that we couldn’t get off with any mechanical means. i really think the bar keepers friend caused it. to be fair, i worked the slurry pretty hard on the glass so maybe the scouring action was too much. at any rate, that was my experience so i thought i would share.
when working with any new product it’s probably smart to do a test patch and make sure it’s compatible with what you are working on. that’s what the directions always say, anyway
and don’t worry shem, it was in an area that no one will ever notice, so it’s not a huge deal. even the etching itself is hardly noticeable. i have “window cleaner’s eye” so it was apparent to me. the average person would have a hard time making it out at all.
I use the 18 22 and 36 for office cleaning. Use a Rubbermaid head. Broke a handle but able to save end piece that holds head and added an old female screw head. Now I can have a 21’ mop handle. I use the 18" as a mop instead of a T-Bar. You can use the regular, dust or scrubber pad and since velcro anything else that sticks to it. Just dunk and wash. Usually have 4 of them so can just drop top and add a new one. Great if you need different solutions going like a special sauce bucket and a rinse bucket. For smaller windows O’cedar and Lieberman have a 12" pad holder. I have been modifying the sprayer cap on the sprayer with surgical tubing so can pump upside down. Like a spray bottle using tubing vice straight plastic tube so can spray upside down. Might get the small fanny pack hudson and run small tubing with a sprayer head to spray while scrubbing. Why pay 250 for indoor WFP setup when I can make my own for cheaper. Works out and in.
I sent out a small sample of Plastee Gritt to you all today. By regular mail. Also three other people too. Try mixing with a DLimonene product. I know the WCR has some samples right now of 16 ounce cans. Ask them about it. These two mixed together knocked off dried tree sap in micro seconds. The mix should eat through silicone caulk also. You be the judge. They should have more samples of the Plastee Gritt as well. So if you need more just ask them. The Plastee Gritt is a plastic (softer than glass) granular abrasive particle size approximately 100 microns.
I think there is a chance that the Bartenders Friend might use a crude silicate as the abrasive. Particles that are only ten microns will scratch. Then products like the One Restore can magnify these scratches. Which become much more visible in the direct sun from the outside at the right angle. I can’t see the acid in the BF etching. Oxalic acid is an organic acid. Also the Goo Gone product is based on organic solvents. Not acids. Please check out some of the posts I did on glass etchants in the blog. I usually test products and procedures first on brand new glass. Not always. But usually. This will tell me if the problem is with the product or procedure rather than whatever is on the glass.
Just wanted to update the thread regarding Bar-Keepers Friend. Tried it the past 2 days on old true divided solid glass windows that were caked with baked on salt as they were right on the ocean. Last year when I cleaned these, I remembering nearly wearing my arm off razoring and steel wooling the windows. This year I decided to try the Bar Keepers friend on them. I put it in a bucket with hot water and then used my scrubber to wet and scrub the windows. Then squeegeed them and buffed them out with a terry cloth towel. I found that not to be sufficient so I added steel wooling them while the BKF slurry was on the window, then squeegeeing them off.
The results were no less than amazing. When I was buffing the remnants of the BKF off the window I could tell that the mixture did more than just clean the glass, it polished it. I would never try this on a new window, but for the old glass that has been baking in the salt, the Oxalic acid and pumice or whatever polishing compound is in that really restores the old windows.
I am going to rethink how I apply it in the future as I want a more neat and contained system. This is sort of a messy process, luckily I was outside.
Neat and contained! Yes. So I am thinking we need to use a coated abrasive particle. Like silica or silicon carbide on paper. Sandpaper. Although not sandpaper of course. I was thinking about an amorphous plastic particle of the same size as the thickness of 0000 steel wool. That being 25 microns. Then we add the liquid chem to this ‘sandpaper’ and scour a surface that has already been soaped and squeegeed. Next soap and squeegee again. I am currently waiting for several samples of acrylic particles. The oxalic acid you mentioned is not without its bio-hazards. But it is an organic acid that would go after alkaline deposits such as sea salt. It also will dissolve in water. Don’t know what the percent of super-saturation is though. I do know sulfamic (another organic crystalline acid) will drop out of water at around six percent forming suspended micro-crystals. Steel wool is an interesting animal. The pores of window glass are about five microns across. Any particle 25 microns in size will easily scratch glass if it is as hard as glass. Steel wool is this hard. About 7 on the mohs. The strands are 25 microns thick. So why doesn’t it scratch? I am guessing because it is not a particle. The long strands probably just rub. This is also why wool has the tendency to ‘polish’.
Any technique developed should be tested on brand new mirror glass samples. Test the surface with battery acid, a flashlight, and a bathroom without windows. Look at the surface straight down the light beam. Just apply sulfuric to one half of the ‘scratch patch’.
