PSA...scraping tempered glass

Thought I would post an example of what can happen when glass that has the fines on it gets scraped.

Those of you just getting into WC need to be very aware of this pitfall. If the razor ‘hisses’ or pops when using it, stop drop and roll.:grimacing:


And just because you can’t hear that hissing and popping doesn’t mean
the glass isn’t being scratched.


I have manufactured some opinions on scraping glass without metal blades.

Interesting, I often wondered if there was a plastic blade available. I just have to wonder if it’ll still drag the fines though.

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That’s why we don’t use scrapers, white scrub pads only and diamond magic. Gets anything off that you would normally scrape, except construction debris. Which brings me to my next point, I highly recommend not doing new construction window cleaning. I know, I get poo pop face every time I say that but make it the construction clean up companies responsibility. Don’t make yourself the fall guy, last one to touch the surface loses.


I agree that a professional window cleaner mustn’t feel obligated to do nasty new construction cleans.
Personally, I’m in the business to make a living, not be a hero. If you’re not prepared to take on that mess and cover yourself from liability, let the clowns who ruined it deal with it.


Does anyone with experience with Glass Renu know if you can take these scratches out without distortion??

I’ve never seen a scratch removal job without distortion. Don’t know if everyone I’ve seen is by someone that doesn’t do a good job or tempered glass is just that poor and doesn’t do well with scratch removal?

If the scratch is 1mm deep then 1mm of glass around it needs to be polished away, that will leave major distortion , most guys say if you can feel the scratch with your finger nail it’s too deep

Blades should scratch if the technique is to push the blade with trapped grit under it. I have yet to scratch glass with plastic blades when delivering a stroke and lifting before repeat. The scratches I’ve seen from other workers come from using a blade in a zigzag manner or using blades on glass that is scratch sensitive. The plastic blade is part of a multiple step process I lay out and by itself it is not a drop in replacement for metal blades. The savings are in your sanity.

This is true but I feel less annoyed at the clownmaster still ready to stump up - than the people who think CCU should cost a third to twice as much. In my experience I could have cleaned 5 to 8 houses in the CCU time for 1.

Originally I was easily bullied but now obtain joy out of rejecting their miserable lowball. Time goes on and I see what happened and get a sick satisfaction of what a total bollocks somebody has made. The other one is where it takes them so long they just give up. I want to say it is like asmr - a warm tingly sensation of joy spreading from upper body to tail bone. I’m sure there is a word for people like me on

Do you like these Mike?

What is scratch sensitive glass? Glass with fabricating debris? Glass with tint on the exterior?

Any glass that exhibits scratches with metal blades even with ideal conditions. For me it is most new glass - using metal is okay on the old material.

Where do you buy those plastic blades for Unger scrapers? I haven’t seen them before and I would like to try them out

Steel works! Exceptional results every time. Tried and true for many decades. Can’t say that about plastic razor blades. Basically useless unless …you know about fabricated debris and don’t want to scratch the glass. Still kinda useless.

WCR should have them. Every window cleaning supply house should have them. Let us know if they work for you. Do you get the same kind of results as you do with a stainless steel razor. I tried plastic pocket scraper blades a few year ago and they are useless in comparison.

So what do you do when this happens? File a claim with your insurance to replace it and apologize profusely?

Without coming across as being snarky, it’s best to just not let this happen in the first place by testing a corner of the window before scraping. This is why I posted this visual warning for the newer folks.

Insurance won’t cover scratches as it’s considered “workmanship damage”.