Nancy’s Painting Blog

Bubble, Bubble,Toil and Trouble

I recently received an inquiry on how to keep bubbles out of that last acrylic varnish layer or finishing coat. I thought other folks might be interested in my answer: (by the way, the title of this article is from my favorite Shakespeare play – does it ring a bell for anyone?)

Acrylic has a tendency to cause bubbling in paint layers, unless you take care to avoid them. Here are some sure-fire tips to keep your paint layer bubble free:

(1)Always pour liquid from one container into another very slowly and carefully from a low angle to keep the fluid from coming out too fast and bubbling.

(2) Mix and stir solutions the day before so the solution has time to rest and the bubbles can pop.

(3) Always use a soft bristled brush (this is usually the main culprit for bubbles). The bristles should be soft enough that you wouldn’t mind using it on your face for applying makeup blush. (Yes, I mean VERY soft) Hogs hair brushes will usually stir up bubbles.

(4) Lightly spray alcohol over the surface before or after applying an acrylic layer and the bubbles will disappear. Spray right after applying acrylic, so you should have the spray bottle ready before applying the varnish

(5) Make sure the surface you are applying the varnish to does not have texture (textured surfaces need to be sprayed not brush applied) and that it is all glossy. Any matte areas will create an uneven absorbency, which can create defects in your varnish application.

(6) Spray applying varnish will eliminate bubbles altogether.

5 thoughts on “Bubble, Bubble,Toil and Trouble

  1. excellent advice. this is such timely information! this week, i've had to carefully remove several layers of acrylic gloss varnish with acetone, before sanding down to the paint- all because of bubbles in the varnish.

    i'll be re-varnishing these panel paintings tomorrow, so will use your tips. thanks so much!

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