The glass industry is way ahead of you - they already have ways to blame you for tempered glass scratches without accusing you of using a scraper.
When I went to GPD ’11 in Finland, there was a study by glass scientists who blamed widespread tempered glass scratches at the Berlin train station on squeegees.
They got invited back to do another seminar on that subject this summer.
And just how did they manage to do that?? Yikes!
They pretty much just assumed that’s what happened.
They scratched up some tempered and annealed glass in the lab, pointed out that the tempered glass looked worse, and basically said tempered glass was more sensitive to abuse - like when window cleaners fail to wet the glass enough and get sand stuck under their squeegees.
Characterisation of the scratch resistance of annealed and tempered architectural glass | Glassfiles.com
I talked to the main author - he said he asked some German window cleaners about fabricating debris, and they never heard of it.
Gary is the man.
So when a window cleaner uses a new blade on tempered glass and gets the “scratchy sound.” (If u are a window cleaner you know what I mean). Then it’s the particles on glass that scratch it. Not the blade?
First thing - and a point I’m trying to make here is - if you’re checking tempered glass that way, and you don’t think you see scratches, you can STILL get in a lot of trouble, because tempered glass scratches grow more visible with time.
You may decide it’s OK, but you don’t know what it will look like in a week.
(And nobody who gets mad at you will believe how good it looked at first.)
The first before/after picture I took was of a fabricating debris scratch I could only see with a shop microscope.
When I found it with the scope, I marked the spot with a Sharpie, so I knew exactly where it was - but I still couldn’t see that scratch with the naked eye.
The next day, after it grew, I could find it.
It’s a very fine scratch - but if you end up with a bunch of very fine scratches all over a window, you could have a big problem.
Two other things:
1 - In window cleaning, it’s never the blade. - sharp or dull.
I know of only one way to scratch glass with a razor - it doesn’t always work, and it only works once.
You cut with the corner of a new blade - as if you’re using a box cutter - and if you do it just right, you may get it to scratch.
But the corner gets dull right away, and once it’s dull, even the corner won’t scratch.
2 - The scratchy sound isn’t necessarily the sound of scratches being created. What you’re hearing is mostly the sound of debris getting popped loose. It might be harmless debris like the plastic interleaving beads some of them use - or some kind of overspray.
Or you may be running over debris that won’t pop loose, like specks of the ceramic paint they decorate glass with.
Point being - you can’t be sure it’s scratching when you hear that - and don’t think it’s OK if you don’t hear all that other noise when you test with a scraper.
There may have been been a few scratches - and they might grow on you.
Holy moly somebody buy the devil a parka! Hell has just frozen over!! Haha!!!
Glad to have you!!
Thanks for your input Gary. I will be subscribing to the wca magazine simply because i now know YOU do articles for them.:). THIS INFO IS INVALUABLE!!!
What about using steel or bronze wool Gary?. Please tell me your thoughts on that. Because it is common “knowledge” among local window cleaners, (at least in my area) that steel and/or bronze wool are “safe” on all glass. As long as it does not have external tint. Thanks again for your info and time.
Gary if you ever get a chance can you check out my website and go to the scratched glass FAQ page and see if my content makes sense to you or if I should change things at all please.
watch it. Don’t take my name in vain!
Metal wools don’t scratch glass either.
But why are they using the stuff?
Are they cleaning all uncoated glass surfaces - annealed and both sides of tempered - with steel wool because they don’t understand there’s a quality problem on the roller side surface of some tempered glass? If so, they are probably working quite a bit harder than they would if they did understand.
Or are they checking tempered glass with a scraper and trying to guess when to switch to metal wools? If so, tempered glass scratch growth part of why they still guess wrong every once in a while.
In my opinion, you should stop blaming other window cleaners - stop claiming you’re trained to detect fabricating debris.
It’s harder for window cleaners to get waiver signed when the competition claims to posess a skill that doesn’t exist.
I’m not blaming other window cleaners there are many many many unskilled laborers in my service area that offer construction clean up through a janitorial company or just untrained people that don’t know how to clean glass that is defected with fabricating debris.
The windows need to be cleaned. so do you have any suggestions on how to solve the problem or do you specialize in pointing out the problem?
I apologize, I must seem a little arrogant with this post because I am, however the fact is that there are millions of pieces of glass with fabricating debris or whatever term used to define the imperfect glass that makes it hard for window cleaners to clean. And there are thousands of scratched pieces of glass in the world now because of it. I can all but eliminate scratched glass when performing construction clean, maybe not perfectly but better than many others, not speaking about WCR members just in general. So is there a problem in manufacturing glass, you tell me. Can it be corrected, you tell me. Have I been as proactive as possible to avoid damaging glass? Yes. Have many others done the same? No. Does that mean they are to blame partially, yes, even if it is the glass manufacturers fault. Unless they stop making defective glass we need a solution not criticism.
Thanks for the feedback though I appreciate it.
Man, I honestly hate to be “that guy.”
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Your not that guy and I’m not going to boil over I don’t want to hijack the thread. That’s taken out of context however. I reread it just to make sure and that’s not whats intended nor should it be considered relevant to cleaning easily scratched glass.
I do claim to be self trained to detect fabricating debris. I’ve been diligent to discover this type of glass therefore I am properly trained especially since no classes or certifications exist I declare myself as the authority on detecting the glass.
Does it really matter? If so I’d like to hear the political answer as to why since I do have a low boiling point I don’t want to be criticized but assuming I can detect fabricating debris which I can by testing a small corner of the glass. Why does it matter if I claim this confidence when selling myself to potential customers browsing my site?
And Mr. Mauer is there a solution if you are the authority on scratched glass what do you suggest. Are you going to make a class on detecting fabricating debris. Are you going to lobby for proper training? Can anything be done about the problem? I’m sorry if I offended you sir. Please don’t think I mean to insult you at all. I appreciate your efforts to help others.
[MENTION=6469]Jaran[/MENTION]. If there is FD, does it cover the whole sheet of glass? How do you detect it in just one corner? I have a job tomorrow and it has a few panes that will be CCU. I really don’t want to scrape, but I am worried I might have to is some small areas. I don’t want to scratch the glass and will be getting a damage waiver, but it would be great if I knew if FD was present first.
It’s simple. Get a waiver signed for every job. Clean the glass. There’s no way to know if the glass is defective or not. If there’s scratches discovered, there’s very little way to know who caused them. Don’t pretend like you can prevent scratches from occurring, and don’t pretend that you can prove that glass is defective or not.
It’s important to note that a waiver does not give you a license to practice stupidly. You can’t clean a window with a brick. But a carefully written waiver will help protect you from the unknown.
