Bubbles — Why They Appear and How to Remove Them

Bubbles are one of the most common issues in resin art, but they're also one of the easiest to prevent once
you know the four main causes.

The four main causes

1. Cold resin or hardener — resin that's too cold looks misty and traps more air when mixed.
2. Pouring too thick in one go — thick pours trap air underneath as they cure.
3. Mixing too fast or too vigorously — fast stirring whips air into the mixture.
4. The object you're coating releasing trapped air — porous materials (dried flowers, wood, some papers) can release tiny air pockets as the resin settles over them.

How to prevent bubbles

Warm your resin. If your resin or hardener feels cool to the touch or looks slightly misty, warm the
bottles in a bowl of warm (not hot) water for 10–15 minutes with the lids sealed, or place them near a low
heater for a few minutes. Aim for a workspace temperature of 21–24°C (70–75°F).

Pour in thin layers. Craft Resin is designed for layering — pouring in one very thick layer traps air that
can't escape before the surface sets. Pour in layers of no more than about 1/4 inch (6 mm) at a time for Arts
& Crafts and Table Top pieces; for larger Deep Pour projects, follow the size-based layering guide in our
Deep Pour depth article.

Mix slowly. Stir resin and hardener together slowly and steadily for at least 3–5 minutes rather than
whipping it quickly. A slower mix introduces far less air while still combining the components thoroughly.

Pour carefully. When transferring mixed resin to your project, pour in a steady stream rather than
splashing, and avoid scraping the sides of the mixing cup — both scraped residue and splashing can introduce
extra air.

Removing bubbles that do appear

• Heat gun or torch: gently pass a heat gun or small torch over the surface, keeping it moving and at a safe distance to avoid scorching. The heat thins the resin briefly and lets trapped air rise and pop.
• Cocktail stick: for isolated bubbles, especially around embedded objects, gently prick them with a cocktail stick or pin.
• Isopropyl alcohol spritz: a light spritz of isopropyl alcohol over the surface can pop small bubbles without disturbing the resin.

For projects releasing trapped air

If you're embedding items like dried flowers, make sure they're completely dry before embedding — residual
moisture is a common bubble source. Layering the pour (rather than encasing the object in one go) gives
trapped air more chances to escape between layers.

Related articles

• Mixing Ratio — How to Measure Resin and Hardener Correctly
• Deep Pour — Maximum Depth, Layering, and Cooling Time
• Cloudy or Milky Result — Causes and Fixes