Construction Clean Without a Blade?

Hi Guys,I am based in Calgary, Canada. I’ve done a fair few construction window clean jobs before but I have usually got lucky and been able to use a blade.The few times I haven’t, the windows weren’t too bad and we used brushes and some wire wool for the small amount of silicone.What would you use if the glass is tempered incorrectly (cannot use blade) and there is lots of construction debris?Do you just use a brush, wool and lots of elbow grease?What chemicals can you use to help you out and how do you use them, do you need to leave the chemical on for a while?I am bidding a big job soon and any advice/tips you have would be much appreciated.Thanks,DamianWindow Cleaning Calgary | Bristol Cleaning

Chemicals can void the IG warranty of the windows. How do you know a blade can’t be used?

I haven’t tested the windows yet but I’m getting prepared for if you can’t.

If the windows are tempered incorrectly they will have ‘fabricating debris’ on the surface and a blade can cause microscopic scratching.

Window Cleaning Calgary | Bristol Cleaning

How does one test for FD?

I read somewhere that u can use the back of a piece of carpet to get silicone off… never tried it tho… without a blade theres not too many options besides a stain remover and a looot of elbow grease… good luck

Thanks Mike.

To answer previous question, without lab eqpt, it makes a funny sound/feels funny when you blade it choose an inconspicuous piece and do it in the corner.

The scratches are so tiny they are hard to see unless you are looking for them so a corner of a minor window is usually fine to test.

Always best to use a waiver (IWCA)

You won’t be able to detect it everytime using that method. There is no test for FD

If you can’t tell the glass is scratched in any way then it probably passes!

Oil-Flo and cement off and a magic eraser. The magic eraser is amazing on silicone.

Thanks for the advice, really appreciate it.

Will try all 3.

Just to clarify, is ‘magic eraser’ a chemical from a window cleaning supplier or the Mr Clean Magic Eraser ? (is it some old window cleaner trick)

Would really be useful as getting silicone off with wire wool is time consuming and fiddly when dangling from a rope.

Thanks again for your straight-forward solid tips.


Over the past 4 years. I have seen this problem alot here in Canada.

I normally treat all new glass as if it could have FD and am very alert to how the glass " feels with a blade" and “sounds with a blade”. Over the years if I am ever in doubt I will normally double my quote for cleaning as it takes double the time. I will use a Mr. Clean Magic eraser and a white scrub pad. I always pre soak all the glass as much as I can to help break down little bits of concrete use lots of water and let it dwell on the glass. Vinagar in the water will also help a little with minor hard water and calcium. I clean then look at it again. May need to “finger pick” the stucco or cement off and re clean. This is a VERY time consuming effort and not fun but I have found that it works well for us.

Hope the best.

+1 on Magic Eraser.

Thanks a lot for your advice. It has obviously come from experience!

As I thought, it’s basically a lot of hard, manual work and yes, will have to compensate in the quote.

Thanks again.

PS love the ‘quote’

There is no field test that can definitely determine the presence or absence of FD. Alternatives to a blade are not foolproof. A waiver is a must in any case because on a CCU you have no way of knowing who handled the glass (or may have damaged it) before you. Oh and FD scratches aren’t always visible w/ a passing glance. They can require specific lighting and looking at the glass at just the right angle to be seen.
Lastly - I would caution anyone against relying on IWCA information to protect themselves against FD at this time.

What about if you clean an area with just a towel and then do the lightly dragging a new blade across and listening for the tinkling sound but then, if it’s there on a bunch of tempered windows, just bring it to the attention of the contractor and then have someone just remove all the debris BEFORE the windows are scraped? Maybe show them, in the sun, what the glass will look like if you scrape bad tempered glass. If they say, screw it, just do it, make sure you have a disclaimer but also you should have a “experienced” glass resurfacing company in your contacts! They will need it! Chemicals and steel wool aint the answer. Plus the crap is still there on the glass, right?! We have seen this scenario many many times. Very frustrating indeed!

So many past threads on this, but here is a few points.

  1. It’s great that we all know FD and continue to learn more! That is being a pro.

  2. FD doesn’t come from incorrect tempering, but bad cleaning while fabricating. Maybe I’m being technical:)

  3. A white pad, vinegar, or magic eraser won’t get cement or paint off.

  4. Use of steel wool or anything used for rubbing on a window always carries the risk of catching debris and scratching glass, but can be used with caution if the window is pre-cleaned and the rubbed object is inspected and rinsed continually. You should still get a waiver signed.

  5. You, a blade, and a waiver, the only love triangle that usually ends well.

  6. One window may have bad FD while others right next to it might not. One window cannot be trusted as a tester.

  7. Waivers are signed easier than you think.

  8. Waivers are not licenses to destroy windows. Be responsible.

  9. Sometimes the best financial decision is to walk away from a bad PCC (or CCU) job.

  10. The FD info on this site is awesome. You’d be surprised what you will find.

  11. Doubling your price should not be a standard for CCU projects. Every project has it’s own difficulties.

  12. Chemicals are an option, do not dismiss them entirely. Sometimes they are a great option. Make sure to do your research, though, as you need to consider risks and short/long term effects. Warranty issues are not always relevant, (nor are IG seal breaks), but use a waiver anyway. The waivers should mention risks from IG seals to possible glass reactions (tin side, etc), and frame discoloring. And use common sense when using chemicals, test and review on each window before moving on. If worries about the IG seals (which is something you should worry about), you can always tape the sides, top, and bottom while doing the cleaning if chemical use is the approved option. Then re-clean with regular soap to get all the chemical off. Some people use goof off, paint thinner, lacquer thinner, mineral spirits, cement off, etc. I’m not saying any of these are good for your situation, I don’t know.

  13. Always educate the owner of any risks, no matter the method or tools you use. Let them make the decision and remove liability from yourself.

  14. IF you know there is a better option for the customer, one that you cannot do for them, tell them. Don’t be selfish.

run Forest, run . . .

just imagine all the things you’ll get blamed for before/if you get paid, it’s a wonderful world in CCU land

I did a job like this once, the guy signed the waiver and I started. Glass scratched here and there but overall things looked good. I showed what happened to the guy and he couldn’t see the scratches. I think in some cases window cleaners critique their own work much more than the customer. Not always though : )

Or if FD is found on a significant number of windows/doors after testing, alert responsible party, then get someone to polish off the FD BEFORE scraping the windows, thereby eliminating the cause of scratching. Or even if you had to grind and polish, its still faster and easier than if the scratches are noticeable. I’ve seen it done! Look on YouTube. Found it…
[video=youtube_share;qnnOLRHHEag]Unscratch The Surface, Inc - Sliding Glass Door Fabricating Debris - Audio Proof - (Pre-scratches) - YouTube

Rick, to remove the FD do you just grey pad and polish, or do you have to go with blue then polish out…?