Liquid masking for painting windows

[Paul F Franklin]

For my office remodel, I had a large window and two french doors to paint. I decided to try liquid masking for the glass since cutting-in 34 panes x 2 coats is not my idea of fun.
I tried some kind of liquid mask many years ago and wasn't impressed, but there are newer products and they get good reviews. You paint (or spray) the masking onto the glass. You don't have to cut it in, any that gets on the wood just gets painted over, and if you have bare wood or bare spots, the mask acts as a primer. You can mask all the glass if you will be spray painting; in my case I'm painting by hand so I just masked a 2" or so band around each edge of each pane. After the mask dries (4 hours to overnight) you paint, with no need to cut-in; you just brush or spray the paint over the masking. After all the coats of paint are applied and dry, you scribe around each pane lightly with a utility knife and then peel off the masking, leaving a nice clean edge behind.

I've only done the 4 large panes so far, but the stuff works great! It peels off easily and cleanly and the paint edge is straighter and cleaner than I could get on my best day just cutting in. I'll probably try spraying the mask on when I do the doors since there are 15 panes in each door.

[Mike Henderson]

Thanks for the tip, Paul. What brand of masking did you use?

Mike

[Frank Pratt]

Yes, please share the brand.

[Tom M King]

I would trust that for interior work, but would worry about how permanent the bond was to the glass on the exterior. I know with old paint, before we had the good quality paint we have today, a cut edge to trim exterior paint would allow water to get underneath, before an uncut edge would. I even did a test, on the same sash to test this theory, back in the '80's. I clean the glass, before painting, with denatured alcohol, in hopes of the best bond possible.

[Jim Becker]

For glass, I just use a utility knife blade to remove any paint that gets on the glass. No masking required.

[Paul F Franklin]

I used a product from Associated: https://www.amazon.com/ASSOCIATED-PAINT-Available-157026-80-400-4/dp/B004SHZWX6/ref=sr_1_1?crid=3TDIW4RWUITGH&dchild=1&keywords=liquid+masking+for+painting&qid=1597236839&sprefix=liquid+masking%2Caps%2C157&sr=8-1


Tom: Yes, not sure I would use it for exterior work, although the info I read said that after a couple of weeks the bond is just as permanent as paint. Not an issue for me since all my windows have clad exteriors and don't get painted.

Jim: I've done it that way in the past. It's probably a toss up if you're painting by hand and have only a little paint to scrape off, but if you're spraying, different story. I may spray paint the doors since I can move them outside and won't need to worry about overspray.

[Larry Edgerton]

I may try that, my new house has 288 panes of glass to paint. Thanks.

[Bill Dufour]

Does it come in a spray can? I only have three original windows that are not white vinyl inside. Can it be used around vinyl windows?
Bill D.

[Paul F Franklin]

Does it come in a spray can? I only have three original windows that are not white vinyl inside. Can it be used around vinyl windows?
Bill D.

Haven't seen it in a spray can, but I really didn't look for it. The brand I bought says in the instructions that it will not peel off "most" vinyl, but I'd probably do a test on your particular windows.

[Jim Matthews]

For glass, I just use a utility knife blade to remove any paint that gets on the glass. No masking required.

+1 works for me.

[Jason Roehl]

So...having painted many thousands of panes of glass in ~20 years as a painting contractor, the “right” way with wood windows is to actually lap the paint onto the glass by a very small amount, say 1/32”. The reason is to keep moisture/condensation out of the wood/glass junction. Scraping should be a last resort, as it will damage that seal.

Takes a very steady hand. That said, in “production mode”, we would often just spray the paint onto the whole window (usually on small panes only, like interior French doors), then scrape. It’s easier to scrape off a full sheet of acrylic paint than to scrape off overspray at the edge of the spray pattern.

[Paul F Franklin]

So...having painted many thousands of panes of glass in ~20 years as a painting contractor, the “right” way with wood windows is to actually lap the paint onto the glass by a very small amount, say 1/32”. The reason is to keep moisture/condensation out of the wood/glass junction. Scraping should be a last resort, as it will damage that seal.

Takes a very steady hand. That said, in “production mode”, we would often just spray the paint onto the whole window (usually on small panes only, like interior French doors), then scrape. It’s easier to scrape off a full sheet of acrylic paint than to scrape off overspray at the edge of the spray pattern.


It would be simple to tape a small spacer to the side of the utility knife when scoring the mask to get that overlap. Once you've scored the mask, peeling it off takes seconds.