I’m not sure you understand the risk you’re taking by testing one corner.
But hey, you asked me about your site - you got my opinion.
If a builder came to me complaining that another window cleaner wanted him to sign a tempered glass scratch waiver - I would tell him to go back and sign it.
If a builder refused to sign my waiver because another window cleaner says he can test one corner of a window and accept all the responsibility, the builder would end up having to hire the other guy.
To which I would add - if you test with a scraper, you won’t’ know right away.
[MENTION=9844]dnefox[/MENTION] I ain’t even gonna pretend to know as much as Gary Mauer on the subject as long as its his thread I will decline to comment on the matter but if you’d like my personal advice on the matter you can pm me. Honestly however I would take his word for it as long as he is available.
I understand quite a bit, that being said I love having your expertise available to help those of us out who don’t understand the science as well as you.
Now that you’ve learned a little about tempered glass scratch growth - you gonna make any adjustments?
Yes I will need to digest this so I can write it differently on my site and start using waivers.
Scratch growth? Interesting thought. The pictures on your web page reminds me of what annealed glass does when you score it dry(without oil that is). The score will pop and click while it gets wider and tiny slivers pop all over. Oil does lessen this affect a bit. I have noticed that if I score at a slower pace there is less popping and the wheel does not get as hot. I have a theory that the heat from the carbide wheel causes the score to widen. No prof. I have spent most days for the last 20 years alone breaking glass, suppose I have had too much time to think.
I am a simple glazier who has never owned a microscope.
Just my observation
Thanks for the info.
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I cut annealed glass for production for a couple of years myself;
The chipping you notice cutting annealed glass is generally gonna be worse on tempered glass - up to 10x worse.
There are some side by side pictures here of scratches to annealed and tempered.
Characterisation of the scratch resistance of annealed and tempered architectural glass | Glassfiles.com
All done at the same speed - no oil or water used.
When I met the author, I asked him why the scratches in the study were so short (only about 1-1/2 inches); he said they had a problem with the various diamond bits overheating and dulling.
I think they know they could have made worse scratches if they allowed that to happen, but I guess they were trying not to ruin their diamond bits.
No surprise. Tempered is harder than annealed at least the outside surface is. In theory then it would chip out more when scored. Correct me if I am wrong.
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My recollection of cutting glass is that every once in a while we ended up with a lite of tempered glass on the cutting table; if I tried cutting it, the cut always looked the same as annealed glass.
Since you can’t cut tempered, we quickly got rid of it - never waited to see how much worse it would look over time.
However, one time the guys laid a lite of tempered glass on the table that was already scored. I distinctly remember that one looked much wider than usual, and now I realize it was because it takes time for tempered glass scratches to max out.
That’s the key here - people think it happens right away, but it does not - it can take hours or days before you see a tempered glass scratch at its fullest.
This is the question I was asked ??? Jaran u do poor work and I want new windows !! Your Ins will pay for it ?? Stan, Pro Window kleening for 32 years
wtf? What * are you talking about. (the f**)
I’m not sure how to measure or estimate what those tempered glass scratches looked like while you were there cleaning, but they probably did get worse in time.
This is the kind of thing I’m talking about. People looking at maxed out tempered glass scratches and wondering why the heck you didn’t see them.
lol I didn’t get it at first, either…
I think he’s just replacing your name for his… meaning, “what would you do” in this situation.
(I think)
Anyone else get fooled by time-delayed tempered glass scratch growth?
Yeah after i sent him a private message about being what the heck he was talking about he explained how he was just getting my attention and that he had lawsuit prior for scratched glass and I’ve never had that problem. Not saying that it can’t happen but I just was thrown off by the randomness of the post.
I think you can set yourself up for trouble by overpromising.
They’re not usually looking for scratches - just admiring clean windows.
But with proper motivation, they’ll spend hours poring over every inch of their glass; they will find everything, and probably come after you harder than the guy who underpromised.
Do you use a microscope for inspection?
Glass Issues: Talking Points - International Window Cleaning Association
“Thorough testing might involve actually trying to cause fabricating debris scratches on each tempered window with a scraper, using bright lights to locate scratches, and then using magnifiers to confirm that they were fabricating debris scratches. This can take hours, and obviously cannot be done if the objective is to avoid scratching the glass.”
Yes
Then I suppose you have pictures
yes
