Tuesday, November 27, 2007

Fabrication debris, metal scrapers don't mix

By Matt Slovick, editor in chief, Glass Magazine

During a presentation at Glass Performance Days in Finland this past June, a newspaper story was shown that stated 75 percent of the glass units at the University of Saskatchewan Spinks addition had to be replaced at a cost of $200,000 because of scratches during post-construction cleanup. The presentation discussed the problem of scratches when metal scrapers hit fabrication debris on glass.

In a nutshell, the glass industry says not to clean glass with scrapers because they can scratch the glass that has hard-to-see fabrication debris; the window cleaners say the scraper is their tool of choice and the scratches are caused by the fabrication debris and not the scraper.

Window cleaners also say fabricators should be following manufacturing guidelines with respect to maintaining their tempering equipment, which would be a huge step in resolving this issue. However, following those guidelines does not eliminate fabricating debris because of the nature of the process, according to those in the glass industry.

I’ve talked to people in the glass industry and the window cleaning business and continue to conduct interviews. The full story will appear in a future issue of Glass Magazine. In the meantime, excerpts have been published in the past two e-glass weekly newsletters.

Higher-performance tinted and coated glasses have been developed during the past decade, leading to more demand for them. Thus, as the making of glass has evolved, the methods of cleaning the glass generally have not.

I understand both points of view, and I hear the frustration in their voices. The scratching is hurting both industries. Many customers are not satisfied. Glass needs to be replaced. Lawsuits are filed.

Simply stating “don’t use scrapers” or “improve the quality of the glass” isn’t solving the problem that continues to exist. I talked to one window cleaner who is using powders and paint-thinner type solutions to clean glass without a scraper. It takes his cleaners more time and is more expensive, but the scratching is not occurring. And that saves money in court costs and replacement costs.

I found a quote recently that seems to fit perfectly in this scenario: “You can’t expect to meet the challenges of today with yesterday’s tools and expect to be in business tomorrow.”


Dan Fields said...


"The Glass Industry Says": In a nutshell, the glass industry says not to clean glass with scrapers because they can scratch the glass that has hard-to-see fabrication debris;(Which should not be there in the first place.) the window cleaners say the scraper is their tool of choice and the scratches are caused by the fabrication debris and not the scraper. (Which is true, since annealed glass doesn't seem to have this scratching issue or fabricating debris.)

Window cleaners also say fabricators should be following manufacturing guidelines with respect to maintaining their tempering equipment, which would be a huge step in resolving this issue. (Another true fact.)

However, following those guidelines does not eliminate fabricating debris because of the nature of the process, according to those in the glass industry.(Why would any offending fabricators admit the problem is with their process and could be easily resolved?)

I talked to one window cleaner who is using powders and paint-thinner type solutions to clean glass without a scraper. (I guess some windows cleaners don't know any better than use ANY solvents around I.G. seals.)

However, no equipment upgrade, cleaning or maintenance can eliminate the occurrence of fabricating debris because of the nature of the process, according to those in the glass industry.
(According to the glass industry pretty much tells the story.) The large volumes of air used in the quench can create airborne particles,(Actually, I believe maintaining the filters in the air quench areas would prevent airborne particles, and particles settling would be on the upper side of the glass, not the roller side, which it is not.) the glass seaming operation creates particles (Which is why glass washers are used and should be maintained on a regular basis.) and the occurrence of glass breakage in the tempering oven (Which would require immediate maintenance to prevent surface defects on incoming glass.) all serve as a source of microscopic glass particles (AGREED) that will periodically (Why periodically, if it can never be helped?) end up in the oven or on the glass and become stuck to the surface of heat-treated glass.

(Mr. Lang has it right when he stated:) "Many washers today include a pre-spray area that removes debris even before it enters the washer, says Bob Lang, sales engineer, Billco Manufacturing Inc., Zelienople, Pa. The company makes and sells machines that wash glass." (and Mr. Bartoe also stated it right when he wrote his 1999 article for U.S. Glass Magazine on Maximizing Ceramic Roll Performance, which can be read at the IWCA web site: http://iwca.org/UserFiles/File/USG%201999%20reprint.pdf, where he states: Debris and airbourn dust in tempering facility will cause defects in the glass...) This is only one of several times DEFECTS were mentioned, that could be prevented. Well worth reading if you want to hear the facts about glass quality from a glass industry expert and how to achive it.

One mans opinion.

Dan Fields

Anonymous said...


You say you understand both points of view. It seems you're making an effort, but I think your readership would be better served if you showed a little more skepticism with the PR attack on scrapers, which protects poor quality glass.

Window cleaners know first hand that some fabricators leave a lot more fabricating debris defects on the roller side of their tempered glass than their competition - and as a result, their glass is prone to scratching. Not just during construction - but throughout the life of the window.

When that happens, it's usually the window cleaner who ends up with the unenviable task of telling a customer they have poor quality glass - but please don't shoot the messenger.

There's something wrong when one side of a tempered lite is so loaded with defects that it can't be cleaned with standard methods, and I think Glass Magazine should look into that. Most of your readers are affected negatively in one way or another by scratched glass due to excessive fabricating debris defects on tempered glass. They don't need PR, they need information.

Fabricators who truly do all they can to prevent the defect rarely produce poor quality glass with scratch issues - but why would anyone suggest that ALL fabricators have the same standard of near perfection.? Why should anyone believe that?

You suggest a failure to adapt to high tech, coated glass products, but every window cleaning association bulletin on this issue is clearly focused on uncoated glass. This is not a high tech coating issue - and fabricating debris is NOT high tech. (There's NO benefit to this defect.)

Paint thinner is definitely not high tech. Mineral spirits have been around longer than the scraper - and would have caught on by now if it wasn't so foul smelling, toxic, flammable, difficult to use and harmful to IG seals.

The problem is not scrapers - it's how to get producers of poor quality tempered glass up to speed with the producers of quality tempered glass that can be cleaned by the same standard cleaning methods as uncoated annealed. We need to talk about that.

Gary Mauer
Window Cleaning Network

Steve Miller said...

I have been in the window cleaning business for over 30 years, and my company cleans millions of windows a year.

I find it interesting that Matt suggests that using strong chemicals to remove typical construction debris to be an answer, how would these strong petroleum based solvents such as chemical paint strippers effect the thermal pane seals & warranties?

We recently cleaned some poor quality tempered glass using alternative methods that did not include use of razor scrapers, yet the fabrication debris still broke off and was caught in the cleaning fabrics with the result of glass scratched so much it has to be replaced. This is a strong example of the fact that “razors don’t scratch glass, fabrication debris does!”

We don’t have issues when there few particles of such debris on the glass; often we see poor quality glass that is so covered in fabrication debris that it caused a considerable drag on the window mops, and any removal of construction type debris causes millions of scratches!

In regard to “new Technology” You know my company has not experienced many problems with the new “high tech” coatings on tempered glass, could it be that the fabrication/tempering companies take greater care in not getting fabrication debris on such surfaces? Or do the coating companies reject poor quality glass?

Why is it that some companies reliably put out quality tempered glass without the fabrication debris problems and at a very competitive price, while others don’t?

I would appreciate it if the glass industry would come out with practical methods to clean such glass; so far what I’ve heard boils down to “don’t let the glass get dirty”

Steve Miller

Anonymous said...

The following 2 quotes are from your article: GANA says "Using a 2-, 3-, 4-, 5-inch and larger blades to scrape a window clean carries a large probability for causing irreparable damage to glass."

And then in the very next sentence GANA says "When paint or other construction materials cannot be removed with normal cleaning procedures, a new 1-inch razor blade may need to be used only on non-coated glass surfaces. The razor blade should be used on small spots only."

Can we use blades or not? GANA says no and then yes. Will heat-treated glass only scratch if a 2" or greater blade is used, but not if only a 1" blade is used on a small area of glass with fab-debris? Why does some heat-treated glass scratch and other does not? Why does GANA first say 'do not use scrapers' and then one sentence later say that 'you may need to use a little scraper'? What does GANA recommend regarding the use of solvents on IG units?

It would be nice (and surprising) if somebody in the glass industry would actually answer these questions.

GANA's PR is double-talk. The glass industry needs real answers and not CYA press releases and heavily slanted articles that do no more than attempt to sling mud and hide facts.

Just answer the questions, please.

Anonymous said...


For a moment let's take a look at the life of a window, one with fabricating debris. It's been discovered "fabricating debris" now what? So the window cleaner uses chemicals and doesn't scrape, do you really think the issue stops there? The "fabricating debris" wait, they lie dormant for an unknown tradesman - example of just a few: painter, sheetrocker, metal fabricator, sign installer, holiday window painter, mason, janitor and consumer. They come along and touch the window with a scraper and WHAM the debris will dislodge and you have scratched glass.

Asking window cleaners to use chemicals that are toxic and harmful to the enviroment, cleaners that can damage windows seals, frames, ledges, sills and are harmful to human health and their employees seems like a huge step away from "high tech". Not to mention the local, state and federal laws which make the usage, storage, and disposal of these chemicals so prohibitive. These laws are in place for a reason...chemicals are dangerous and harmful. Yet still, even if the glass was cleaned with chemicals it does not solve the problem of the "fabricating debris" dislodging during the life of the window. One way or another, one trade or another the debris will dislodge and scratch the glass it's just a matter of time.

Very clearly this poor quality glass is defective. Why you may ask? Simply this.... there are fabricators who produce quality tempered glass that does not have the "fabricating debris" and during the life of that window it won't scratch when exposed to other trades it doesn't scratch even when it is scraped with a 1 to 6" scraper.

Why can't we ask that fabrication quality be the same for all fabricators? To state in your article that the other side is asking for flawless glass is absurd, we are simply asking for a quality standard that can be cleaned according to window cleaning industry standards. There are fabricators who already produce quality tempered glass that can be scraped, what is wrong with expecting and demanding the same standard of quality from every fabricator?

Even when glass with fabricating debris is cleaned according to GANA'S guidelines with a strip washer and small areas with a 1" blade the "fabricating debris" still release and scratch the glass.

Once glass has been produced with "fabricating debris" the debris and the issue of scratching will remain for the life of the window regardless of the cleaning procedures. I can only hope that the "Glass Industry" begins to make changes to sincerely address this issue soon.

Alissa Wenning
Blu Sky Window Cleaning

Tim Bloom said...

Over 35 years ago my father paid his way through college cleaning windows and passed along the trade to my brother and myself. Needless to say, I value glass, as cleaning it puts food on my family’s table.

We live in a less than perfect world, with less than perfect glass and less than perfect window cleaning procedures. Consider this: It is doubtful that glass manufacturers want to produce defective glass any more than window cleaners want to damage glass. The one commonality we share: We all want to maximize our profits and minimize our risks.

The ongoing fabricating debris/scraper debate seems to be framed in an either/or solution. Could it be possible that other solutions may exist?

Aren’t there acceptable levels of defects in glass? The ASTM (American Society for Testing Materials) seems to think so.

Instead of manufacturers and window cleaners pointing fingers, maybe there are other solutions that have not been adequately addressed?

I personally know of two solutions to scratched glass that my company utilizes to mitigate glass damage and increase profits. One solution is temporary, the other is more permanent.

The temporary solution we offer to glass shops and contractors is a thin protective barrier that is applied as a liquid and dries to a semi-transparent rubbery film. Construction debris accumulates on top of the barrier instead of coming into contact with the glass. We simply peel off the film and the construction debris, eliminating the need for razors and solvents. Contractors really appreciate that glass damage caused by scrapers and other construction trades is greatly reduced and often eliminated. We have applied this barrier to glass that had fabrication debris present without causing scratches during the removal of the film. This additional service adds more profit to our bottom line while reducing our liability. A real win-win.

The more permanent solution we offer is a patented technology that actually changes the molecular surface of the glass, making it more resistant to scratching. Most construction debris won’t adhere to the newly transformed glass surface. The debris that does is easily removed without scrapers or solvents. This service also adds profit to our bottom line while reducing scratched glass liability.

I respect the opinions of glass manufactures and window cleaners alike. All parties must find a common ground solution. A solution that in the end will benefit the consumer, who in reality, is the entity the manufactures and cleaners really serve.

If manufactures can improve the quality of the glass they manufacture, they should. If window cleaners can achieve the end product of clean glass without damaging it, they should as well. If any solution causes financial losses for either party, it is not a sustainable solution. We all manufacture and clean glass to make a profit.

We should recognize that without the glass manufacturers making glass, even if it has fabrication debris, we would have no glass to clean.

It’s not a perfect world we live in, but there are other solutions to this nagging problem of fabrication debris. Explore them for yourself. Who knows, you may find that the issue of glass fabrication debris is really a financial opportunity in disguise!

Tim Bloom
Brite & Clean, Inc.

darryl said...

As long as there is fabrication debris there is poor quality glass.
If the window washer does not find it some other pood soul will. The sign man removing vinyl letters or the tint man. Fabrication debris was not a problem years ago. Window washers have been using blades for years. The customer deserves good glass.
Darryl Kommers
Laurens SC

Gary Mauer said...

"We live in a less than perfect world, with less than perfect glass and less than perfect window cleaning procedures." - Tim Bloom

That's just a sales pitch for protective coatings - when fabricators produce tempered glass with a quality surface, the scraper is the perfect tool.

There are problems with glass quality that need to be addressed. Anyone who doubts that should read this USGNN article,
- "GANA says it has also promoted the fact that there are procedures that can make the glass better, and they have worked to bring this information to the tempering industry."

It's not as if you get a discount for tempered glass that's loaded with fabricating debris defects - so why should you have to pay extra for protection?

Gary Mauer
Window Cleaning Network

Jim Willingham said...

My name is Jim Willingham of New Day Window Cleaning of Lubbock Texas. I have been a Window Cleaner for 37 years. This was not a problem 10 years ago but now all of a sudden its the window cleaners fault for using a tool that never scratched glass before. Come on!!!!

This is a quaility issue with the temperers. Cheapest bid goes.

I spoke in front of the Society of Glass and Cermic Decoratoers in 2000 and showed them that a scraper/putty knife will not scratch glass on non tempered or heat strengthened glass. 5 of the largest MFG's were thier and saw it. To say that the window cleaning needs to get into the 20th Centry is a total cop out, they produse debris free glass everyday in lamanated glass.

The temperers are at blame here for being in a hurry to produce glass.

I am a former (IWCA) President and we fought another ANSI Committee for 10 years on another issue and now that committee is disbanned and the Standard was Yanked because they refused to consider comments that effected "those involved in the industry". We are involved VERY involved.

We are like Plastic Surgens, we clean and the customer looks through the clean glass to see any scratches or blemishes. If the glass industry continues to stuff their heads in the sand and make a statement like " use something else to remove the debris" we will attack your Standard and win.

Hell, the glass industry says to use a mild detergent to clean with but will not sign a release for ANY product to use on IG units or low E glass. I asked them for one on Joy and was refused.

Clean up your temperers act or we will have to address your standard.

Jim Willingham
New Day Window
Lubbock Texas

Gary Mauer said...

I agree with most of what Jim Willingham said, but I don't think this is a problem with "cheap" glass.

From everything I've heard, the glass industry is very competitive regardless of surface quality.

Poor quality tempering may be done in haste, but I don't think it costs any less - just as I don't think it costs any more for the good stuff.

Gary Mauer
Window Cleaning Network

Jim Willingham said...

Gary I am surprised to see what you wrote, we are in the manitence business. Less time cleaning the tools means more glass per hour produced means cheaper glass for them.


darryl said...

It's not what the customer pays that makes defective glass cheap.
It that defective glass is worthless

Henry Grover Jr. said...

Hi Guys,

I have been consulting as of late with two construction companies dealing with the fab debris problem. They had no clue about this problem. It still surprises me how many window cleaners also don't know about the problem. I am trying to get the construction companies to let me inspect the windows before the purchase or at least before installation. Maybe if the big guys stop buying the stuff, the tempering fabricators will stop making it? Who knows!

Henry Grover Jr.

Rick Evans said...

Just wanted to let everyone know that we just got back from Chicago where we completely "Re-Surfaced" 20 Low Quality Large Tempered Windows and Doors. They had the worst fabricating debris I've seen thusfar. Didnt even need a microscope to see it! It was thick! The large (7'x 8')West facing windows were a bit of a challenge since there was zero tolerance for any swirls or haze. In other words, they had to be flawless! These were 900k condo's in downtown Chicago. All had a view and all had to be perfect. Some had bad scratches on both sides! Usually though, one side was significantly worse. The bottom line is...We have come up with a way to effectively re-surface crappy tempered glass. So if you run into this problem and the manufacturer doesnt want to replace, give us a call. We have a super fast crew and we can travel anywhere if the price is right. The Chicago job was about 1500 s.f. and we had 3 guys and finished it in 6 days. We were averaging about 100 sf per man/per day. We were flown down to Florida to do a demo in a 30 story bldg with the same problem. This time, 7000 sf of damage!! They want it done! So anyone who wants to make a little referral fee, feel free to call me and we'll hook you up (5% of the job) The Florida job is 120K (5%=6k). Anyway, call me direct. Here's my cell. 805-295-9020

Rick Evans

Blouis said...

Hi, I'm a homeowner who's expensive new windows were destroyed due to a cleaner using a scraper on tempered windows covered with fabrication debris.

We are about ready to file suit against the window and glass manufacturers and I would love to hear from anyone who has had experience with this. thanks


Anonymous said...

I have also been in the window cleaning industry for 30 years and our company has done thousands of large construction clean projects during that time here in Florida.

I agree with others that scratched glass is more of a problem now than it has ever been. Obviously something has changed and it is not window cleanign methods, it is glass quality.

That being said.....guys....if you scratched it you are most likely going to get your butt sued and end up having to pay for it unless you are very lucky. Furthermore if it is a large claim your liability company might say "Sorry, we are not covering your negligience."

If you have a lot of money you can defend you your rights to have used use razor blades. But I am sorry to say, in my experience, if you did it, you are screwed. One lawsuit against a cleaning company here in Tampa Bay is for $3million. It is a high rise condo, inside scratched all to hell. Unavoidable, windows were trashed, even concrete on some of them. They are screwed and could go under because of this!

Bottom line, if you are going to use razor blades, get some sort of waiver signed or, at the very least, communicate in writing BEFORE you start scraping, that you will be careful and do not anticipate any scratching, "However, we can not be held liable if some scratching occurs."

My 3 Cents advice today...

1.) Do not use razor blades
2. Or cover your butt in writing somehow
3. Or walk away from the job

John R.
Founder Bay Area Window Cleaning
Tampa Bay

Rick Evans said...

The Solution??
We have a patent pending method for resurfacing large areas of even fabrication debris tempered glass...period. Check our references. Plus we have many more. Currently working on Jennifer Annistons new house in Beverly Hills. and yes, fabrication debris is there too! The good news is, we're fixing the problem. Even with an awesome view of Century City. No distortion! We're resurfacing large areas of huge windows and sliding 9 ft doors! Therefore, I say, we have the answer to this problem. SO lets stop the bickering and start working with the solution. Youre not going to change the way the glass is made. But you can at least start working on the way to give the people what they want, clear glass without scratches! Contact me with any questions. Rick Evans 805-295-9020 or 888-986-7272 or rick@unscratchthesurface.com or www.UnscratchTheSurface.com

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