Resin Bubbles – Why They Happen & How to Prevent Them

Introduction

One of the most frustrating problems in resin art? Air bubbles.

They show up in your clear pours, get trapped under embellishments, or rise too late to pop—ruining that perfect finish.

In this guide, we’ll explain what causes bubbles in epoxy resin, and how to minimize or eliminate them completely using Mycast Epoxy Resin and the right techniques.

Why Bubbles Form in Resin

1. Fast or Aggressive Mixing
   Stirring too quickly creates air pockets that get trapped in the resin.
   
   

2. Cold Resin or Moulds
   Thick, cold resin traps more bubbles and resists flow. Cold surfaces don’t allow bubbles to rise easily.
   
   

3. Pouring Too Quickly
   Dumping large volumes creates turbulence and microbubbles.
   
   

4. Trapped Air in Embedded Objects
   Flowers, charms, stickers, and even glitter can release hidden air when submerged.
   
   

5. Resin Curing Too Fast
   When mixed in large volumes, the heat from curing can “lock in” bubbles before they rise.

How to Prevent Bubbles with Mycast Resin

1. Warm Your Resin Slightly

• Place your sealed resin bottles in warm water (30–40°C) for 10–15 minutes before mixing.
  
  

• This reduces viscosity and allows bubbles to escape more easily.
  
  

2. Mix Slowly and Steadily

• Use a folding motion—not whipping—to mix.
  
  

• Stir for 3–5 minutes, scraping the sides and bottom of the cup.
  
  

3. Let Resin Sit After Mixing

• After mixing, let the resin rest for 5–15 minutes (depending on the type).
  
  

• Mycast 2:1 Casting: 10 mins
  
  

• Mycast 3:1 Casting: 20 mins
  
  

• Mycast 2:1 Coating: 15 mins
  
  

• This gives bubbles time to rise naturally before pouring.
  
  

4. Use a Heat Gun or Torch After Pouring

• Quickly run a heat gun or small torch over the surface to pop surface bubbles.
  
  

• Don’t overheat or hover in one spot—it can cause mould damage or bonding issues.
  
  

5. Pre-Seal Embedded Items

• Coat items like flowers, photos, and paper in a thin layer of resin first.
  
  

• This prevents air from escaping during the final pour.
  
  

6. Pour in Thin Layers

• For deep pieces, pour in stages to reduce trapped air and control the exothermic reaction.
  
  

7. Use a Pressure Pot (Advanced)

• A pressure pot compresses bubbles during curing, but is optional for most Mycast users.

What Not to Do

1. Don’t use water-based pigments (they introduce moisture and air)
   
   
2. Don’t mix cold resin straight from a cold room or fridge
   
   
3. Don’t pour resin during very humid or rainy days—humidity increases bubble formation
   
   

Final Takeaway

With proper preparation and the smooth, low-viscosity formula of Mycast Epoxy Resin, you can dramatically reduce or eliminate resin bubbles—even without a pressure pot.

Warm your resin, mix slowly, let it settle, and use heat smartly—these four simple habits will make every pour cleaner and clearer.