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Decoupage Bubbles on Glass

What to Do When Decoupaging a Non-Porous Surface

Bubble Formation is More Likely When Decoupaging on a Non-Porous Surface Like Glass

Hoping to find a crafter who can answer a question.  

I am doing decoupage under glass using napkins. The first two came out beautifully but the next five had so many air bubbles it was impossible to remove all.

I tried using Elmers glue and Mod Podge with the same result. Could humidity be causing an increase in air bubbles?

I have searched the Internet for an answer.

I saw your tips to remove bubbles, but not what causes bubbles in the first place.

Hope you can help me.

Carol

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Air bubbles on a decoupage project are caused as the decoupage medium dries and loses volume. The image, which lay perfectly flat when you applied it, was soaked in medium and possibly swelled up by it as well.

Oil-based media dry and cure as volatile solvents are released into the surrounding air. Water-based media dry and cure as water molecules evaporate into the surrounding air.

So water or solvent molecules are escaping from the image itself, as well as from the space between the image and substrate (in this case glass).

Both Mod Podge and Elmer’s Glue are PVA water-based media which dry by evaporation. On a non-porous surface like glass, evaporation can only occur in one direction - through the decoupaged image.

High humidity will slow evaporation. If the weather has turned more humid since you made the first two projects successfully, you’re now dealing with a double whammy: 1. all evaporation must occur through the image because of the glass substrate; and 2. the decoupage medium will cure more slowly because of the higher humidity.

Bubbles occur where the surface of the medium dries and forms an occlusive film trapping air underneath. Usually some moisture can continue to escape (though more slowly) and the bubbles will resolve on their own (given enough time).

Are you using the same type of napkin as on the first two which were successful? Do the napkins absorb moisture well?

If they have some type of water repellent coating, they could be trapping air and practically preventing evaporation.

I try to smooth out whatever bubbles I can before the medium starts to tack up. Then I relax and let nature take its course.

I hardly ever decoupage more than one item at a time unless they’re small like coasters because of the need to keep an eye out for bubbles requiring attention.

If high humidity is a contributing factor, try drying the project directly under a fan (like a ceiling fan) or use a blow dryer on low heat.

Hold the blow dryer about 10 inches above the project and move it evenly over the project. You don't want to dry the project itself with the heat but rather, you want to create dry air above the project to speed evaporation from it.

I hope this helps.

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