Cleaning Glass Panes

Remove old panes & putty, cut & clean glass, putty & paint.
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Cleaning Glass Panes

Postby johnleeke » Mon Apr 15, 2019 3:34 pm

Glass Cleaning, Wet Wash Methods

These methods and materials are for cleaning glass panes before glazing and painting. Can you keep a secret? At the risk of getting sued by the window cleaner product manufacturers, I'll tell you two secrets they definitely do not want you to know. But first, here are the basics of glass cleaning.

To remove crusty putty and paint from glass that has been removed from the sash, put it to soak in water in a bucket or tank. It's best to put the glass in vertically, laying glass flat can result broken glass when you try to lift it out. Adding a mild detergent (such as Simple Green) will help loosen dirt and debris. Do not add vinegar or high powered detergent (such as Dirtex or TSP) because it may etch the glass. Usually an over night soak, up to a few days, is enough to completely loosen the debris.

Brand new glass does not need to be soaked, but it should be cleaned. It may have residues of the manufacturing process, and oil along the edges where it was scored and cut.

Hand Cleaning Methods

Safety: avoid cutting your fingers by always moving your fingers perpendicular to the edge of the glass, moving your fingers parallel with an edge will more readily slice open your skin! When wiping glass panes use a diagonal stroke, this keeps your fingers moving roughly perpendicular to all the edges.

Work Surface:
There are special sheet rubber materials designed and sold to cover professional glass workers benches.
"Make do" materials can include:
- a white terry cloth towel spread over any truly flat surface, white makes it easier to see the dirt you need to clean off
- foam rubber carpet underlayment
- (let us know what you use...)

Commercial Cleaning Solutions

Secret #1: All the commercial glass cleaning products are very costly compared to making your own. One of the Windex products can cost about 7 dollars per quart. You can make your own that is more effective for 5 cents per quart.

Cleaning Solution Recipes:

3 drops dish detergent, 4 oz of alcohol, a tablespoon of vinegar in about 12 ounces of water --Jade Mortimer, professional window specialist

28 ounces water, 1 TBS white vinegar, 4 ounces alcohol, 2 drops of dish detergent. The alcohol makes it dry streak free and removes grease and other substances that detergent and water won't. You will like the results. --Dave Bowers, professional window specialist

Water. Ordinary drinkable tap water usually works well. Fresh distilled water is non-ionic and can clean better with less damage to the surface in difficult cleaning situations.

Alcohol. Alcohol acts as a wetting agent so the solution "wets" the glass surface more readily, and as a solvent for oils. Perhaps the best type is Ethanol (ethyl alcohol), as sold at paint shops for use as a solvent. Many window specialists use the more readily available rubbing alcohol, which can contain isopropanol (isopropyl alcohol), oils and other additives that can leave a residue behind. If you are getting streaking from your washing solution and are using rubbing alcohol, try switching to ethanol.

Vinegar. If you put vinegar in your cleaning solution and have problems with your paint peeling up along the glass, give your glass a final mist and wipe with a solution of plain distilled water with just a bit of alcohol.

Ammonia. Household ammonia (dilute ammonium hydroxide) is also an ingredient in many window cleaning formulas. It is more caustic and hazardous than other ingredients and not recommended for glass cleaning unless needed to solve specific cleaning problems.

Secret Ingredient. OK, this is the secret ingredient the window cleaner manufacturers absolutely do not want you to know about. When mixing up your own cleaning solution don't forget to add this powerful secret ingredient: 1/4 drop blue or green food coloring. Yes, that's right, it's just food coloring! Without it you just cannot get your glass clean, but with that blueish-greenish tint you've got real CLEANING POWER. Of course, if you also want the KICK of SPARKLE you have to dispense your solution from one of those fancy window cleaner spray bottles with the sexy-curvy shape. Oooh, la la! (Sure it's "sexist" but who cares if it cleans the glass?) Spritz, spritz. Now that's what I call clean!"

Wiping With...
- Paper towels, they work, but for me they are too costly in dollars and environmental damage for regular use
- old newspapers, they work, some workers love them, some workers don't
- used cloth diapers, very effective, available at diaper service companies, launder and reuse
- old cotton T-shirts, very effective, launder and reuse
- microfiber cloths, from the auto parts store, launder and reuse
- What's with all this wiping stuff? Real Window Washers use a squeegee!


Before scraping put a little soapy water on the glass to avoid scratching it.

Use ordinary single-edged razor blades in a handled holder. 3" and 4" wide razor scrapers can speed production on larger panes of modern flat glass, but may skip or scratch on older wavy glass that is not truly flat.

Dull and ragged razor blades can scratch some softer glass types. Replace blades before they get dull.


Spray cleaning solution directly onto the glass if the glass is not already wet from the soak tank. Remove heavy debris and soiling with a scraper. Spray again, wipe off. Spray with plain water, wipe off. Set aside vertically to dry.

To control the water and 'mess' I spread a bath towel out over my bench top, and lay the glass on that, flipping the pane over edge-for-edge, cleaning each side and flipping it on over to the right after cleaning each side, onto cleaner parts of the towel. First I scrape off any remaining paint and putty, then wash each side twice. I have 3 or 4 towels I use for this and launder them when they get dirty. Lead-safe work: the towels are very effective at catching and holding any lead-containing debris. They are laundered separately from household laundry.

Steam Cleaning
If you have a steam box or steam chamber for deglazing you can use it for cleaning off stubborn residue. Spray your cleaning solution on both sides of the panes, then set them vertically in the box so steam can reach both sides and steam away! The panes could be steamed while steaming the next set of sashes. Scrape and clean as soon at they come out of the steam. Do not use the portable steam head, the differential heating of hot in one spot is too likely to crack the glass.

Sonic Cleaning
Some shops are using sonic cleaning tanks to reduce glass cleaning time. The sonic equipment vibrates the water at extremely high frequencies, which helps loosen the debris. The time saved can be dramatic. The equipment is not inexpensive, so you have to be cleaning a lot of glass to justify the capital expenditure.

Cleaning Tips

Hot tips just in from Bron in Indiana:
My grandmother, who ran a hardware store, used whiting and water as glass cleaner, work it, let dry, then she would buff it off. An old picture framers tip, having trouble cleaning that glass, sprinkle some whiting on with your regular cleaner, and wash as normal. I use the microfiber clothes, one that gets pretty wet, then a dryer, second cloth to polish, and the whiting added to the formula presented earlier, will even remove masking tape goo.

"I keep some whiting in a pint container and just dab a dampened rag in it for cleaning when needed. Works great!" -- Andy Roeper, professional window specialist

Cleaning paint off of glass:

"We use a commercial vc4000c vapor steamer to remove old paint from windows." --Fiorella, Any House Cleaning Services, Winter Park, FL

Stubborn Cleaning Problem?
Instead of guessing, get systematic. Look at it with a pocket microscope to see physically what it is and what the surface of the glass is like. (a deposit of mastic film on smooth glass with grit on top, or porous glass surface with embedded paint binder and pigment, etc.) Try three completely different methods (mechanical, chemical, light). Select the one that works best and try three completely different variations (CHEMICAL: acid, caustic, solvent; MECHANICAL: white melamine plastic sponge, brass brush, lubricated scraper; LIGHT: infra-red for heat, ultra-violet for chemical bond breakdown; etc., etc., etc.) No progress? Then try some combinations: the mildly caustic ammonia plus ultra-violet light, etc.
Within a hour you should have something that works.

More discussions on cleaning glass: ... hp?p=10124

Discussions on washing windows: ... =2&t=29014

What are your favorite glass cleaning methods and materials?

Site Admin
Posts: 166
Joined: Thu Aug 29, 2013 8:21 pm
Location: Portland, Maine, USA

Razor Blade Scratches

Postby johnleeke » Mon Apr 15, 2019 3:35 pm

With the glass cleaning methods detailed in my book, I clean all the glass for five or ten windows before I change the razor blade, and never get glass scratches. I think the details that lead to no scratches are:

-- while the glass is still in the sash and dry, dry brush off the glass and sash to get off any gritty dust. If they are particularly dirty I might also wet wash them with simple green and a soft scrub brush.
-- always wet the glass with detergent cleaning solution to lubricate the scrape
-- always scrape going forward, then lift the blade to go back for another scrape. Dragging the blade back can catch grit under the blade that might scratch.
-- I have two blade holders. When a blade get dull I use it to "chop" the hard putty off the edge of the glass. When it's too dull for that I put in a fresh blade and use it for scraping the surface of the glass, and the other holder goes to chopping edges.

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