Fabrication debris doesn't exist


So going around at the moment is that FD a term we have all accepted over the past 20 years, isn’t actually a thing and glass fines do not fuse to the glass during the tempering process…

I was a member of that world email group for a while now its been more or less silent until yesterday when there was over 20 posts about IWCA removing and denying that FD are real.

here is a copy and paste of the explanation:

"_Group, I like everyone’s analogies on this issue that has confused windows cleaners for years. _

Before I offer some insight on glass research, I would like to first state one thing. Earlier today I laid out the nine major items that the IWCA has accomplished thru the Glass Committee for window cleaners. Not once did I mention “fabricating debris” in that email because the IWCA Glass Committee has always striven to do much more than have a single minded focus. If you have missed that, please go back and read the nine points… Yes - window cleaners are in a better position today than ten years ago.

_With that said, I see much confusion in the many comments on the subject of fabricating debris. The fact is, when this theory developed almost 20 years ago it did something - it gave window cleaners a simple explanation for what we saw in the field on a daily basis - that heat treated glass was different and it scratched randomly for no apparent reason. It was a simple explanation, carved out with much field observation and out of the box thinking along with an elementary collection of microscopes… _

However, 20 years later things have changed… The microscopes these days that look at the very same blurry images that appear to be what we would have called “fab debris” comet scratched years ago can now show with clarity what is actually on the surface. And it’s not pieces of fused debris from unwashed glass that went thru a tempering oven. Science showed us that.

Move forward, and despite sending sample after sample to glass scientists around the world no one could locate the elusive fused particle of glass dust. Not a single scientist anywhere on the planet attributes scratched glass to fused glass particles from unwashed glass.

Move forward a few years, science proved that glass particles in a tempering oven do not melt and fuse like we had imagined they did - no they actually brush off the surface during multiple experiments.

Move forward again glass science studies explained to us the chemistry reaction of water/humidity with the soda lime silica glass surface and the reaction going on there, having multiple effects on glass surface chemistry and thus the wear patterns.

Move forward again and we learned that yes, heat treated glass surfaces (both heat strengthened and fully tempered) are very different than annealed glass. As flat glass goes thru stages of heat treatment, although it becomes more impact resistant (thus meeting safety requirements) it also becomes easier to indent with a particle, “softer” if you will. Yes - it is easier to initiate a scratch on heat treated glass than annealed glass in the lab.

_Future studies will be concentrating on the variations of flat glass tin surface verses air surface, using both wear pattern tests and indentation tests. Some scratched glass recovered from job sites exhibit similar patterns with regard the tin surface. Other observations are brand new, even to some glass scientists. _

_Areas that need attention and further studies are varying amounts of tin in the surface based on where in the ribbon the Glass came from (basically tin gets absorbed a varying rates on the ribbon from middle to outer edges and depending upon thickness and other factors); the mixtures of various tints into the raw glass and how that effects the glass surface; and a few additional surprises. _

We need to look beyond assigning a simple explanation such as “fab debris”, and look to the extensive research being done around the globe. Yes, heat treated glass surfaces are different. Yes, many times heat treated glass scratches easier than annealed glass. We all seem to agree on these same observations in the field and now science is backing up our observations.

So why argue about the 20 year old fab debris theory and instead look with an open mind to what research and science is teaching us. This is not a conspiracy, it’s just old fashioned research in a modern world.

_In summary, it would be easy to say “all glass is the same and when we see changes in surface behavior than its defective.” But listen, that’s not true. The glass surface is much more complex than that. _

Which brings me back to my nine major points that the IWCA Glass Committee did to help window cleaners, none of which focused on fab debris but all of which focused on real world issues in the field.

_As far as the science goes, it is fascinating - and it is showing us things in the lab that we have seen symptoms of for years in the field - but it is a journey. You all have a choice to either embrace a 20 year old theory that may have been well meaning and served a simplistic purpose at the time, or open your minds and learn more about the product you clean every day. _

The choice is yours and I respect your individual right to choose. As always I am open for discussion publicly or privately."

So for all those that don’t receive these emails here is some news you might want to be aware of.


Wow. Thank you for sharing @Steve076.


This is quite opposite of IWCA’s stance on glass scratching. But I seem to have missed WHY glass scratches. Is it because heat treated and tempered glass surfaces are “softer” and more prone to scratching from even scrubbing techniques. Another thought, does agitation from WFP brushes scratch glass too?


I’m sure this topic isn’t going to blow up…

I’ve been on many many jobs where I can ‘feel’ the—

(insert whatever word you’d like here. If “fab. debris” is no longer correct I’ll call them “tiny little bumps”)

– when using a razor on N/C glass.

Those tell-tale “clicks” the blade makes has always told my the tempered glass is probably going to scratch. Sometimes those “tiny little bumps” will even stop a blade from moving across the surface of the glass.

I have also run across “tiny little shards” that are attached to the glass, almost like a clear splinter that is part of the glass surface that is large enough that a blade won’t go over it. Not that often but, it doesn’t surprise me anymore.

I’m not a big association, I’m just a guy who cleans glass every day.

Some tempered glass has a texture to it (almost like a mist of overspray) and it usually scratches.

Call it whatever you’d like.



Such a frustrating topic.

One observation I’d like to mention is that in my years as a window cleaner, I have often noticed that balcony railing glass often scratches on one side but not the other. The glass companies have to have some explanation for that. So if it’s being said that heat treated glass is softer, is it only softer on one side? And what is the significance of that ‘tell tale’ sound we hear on certain areas of heat treated glass that occurs while the scratching takes place?


I think that might be related to which side is the tin side I think that’s what the article was saying


Also, contaminants during the construction or painting process can be anything of unknown nature to the window cleaner. What scratches and what doesn’t? Paint can even scratch if other contaminants are lodged in with it.


It pretty funny when I think about it, almost 20 years ago when we first encountered This problem my supervisor at the time said" Its just soft glass" at the time I made the assumption that he was wrong and did my own research and found the FD discussion.
Turns out he was right all these years .


Great thread. It has shown us there is much more to learn. I really am hoping everyone accepts what real science is showing us. I decided to play around with brand new annealed glass a month ago and learned how to make it prone to scratching. Then I learned how to change it back so it wouldn’t take a scratch. When we truly understand exactly why glass scratches and have the technology to change it so it won’t scratch, we will have a fantastic service to offer. By the square foot!



I feel pretty dumb after reading that.

I’m doing my homework next time. Jeez, I’m supposed to be the professional and like a dummy I didn’t even really question anything just took it for fact.

So, basically…“I don’t freaken know” is my answer now to what exactly it is…

I’m curious as to what it is tho. I mean, every fact that was stated after thinking about it, it true. Tempering ANYTHING won’t make something fused or welded to the object being Tempered or hardened. The heat isn’t high enough, you can’t take it to the melting point, just below it and as far as I remember, a controlled lowering of the temp.

Anyhow. Thanks for the information man.


So Dan Fields was wrong all these years too?
What a Construction Window Cleaner Sees

Be sure to use a good wetting technique and let dwell before trying to remove construction debris.
Common Causes of Scratched Glass


Guess I need to throw away my 24" razor blade.


Well as far as the industry is now, um yeah you can if your going to use a blade on tempered glass, and if you do and it is found to be scratched after you have cleaned it whether or not you tell whom ever it may concern the particular way you used a tool that is not permissible by the WHOLE industry now and every supporting industry, has now not condoned… About now most scratch waivers will become obsolete as they most are blaming a defect in the glass.


Whew, I’m sure glad to know fabrication debris doesn’t exist. I knew it all along. Scratches are due to witchcraft. Turn our crops bad, scratch our glass, throwing our kids in ovens, spinning wheels making me sleepy… Time to get a mob together.

Oh, Dan must be pissed.


It was the information available at the time, even have a glass manufacture stating that the tempering process caused “pickup” on he glass, they also used the information that was available at the time.

The general consensus over the years is there is something about a lot of tempered glass which makes scraping problematic, there are those who have chosen to ignore it and blame the quality of the glass demanding higher quality glass, then scrap it destroying the glass and standing behind a waiver that absolves them from the damage they were well aware they were causing.


Yeah, but Dan spent a LOT of time with a microscope proving FD.


At the end of the day whether its FD or soft glass the primary focus is a BLADE WILL (likely) FUCK IT UP!




But its only “fucked up” in relation to the use of a razor blade on it the rest of the pane is 100% functional and perfect to the naked eye.

So that’s where WE need to adapt our cleaning methods and educate builders and other trades that we are no longer the magic window cleaners removing all of their laziness in a breeze.


Its actually the razor blade manufacturers who are putting diamond dust onto the blades to cause scratches to the glass so they can sit back and laugh.