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Home ยป How to Get Rid of Bubbles in Resin – Once and for All

How to Get Rid of Bubbles in Resin – Once and for All

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Bubbles

Epoxy resin can be used to make beautiful things, but air bubbles are an unfortunate part of starting out with this medium. Here are my best tips to get rid of bubbles in resin once and for all:

  1. Use the right type of resin
  2. Use high-quality resin
  3. Cast in a warm room with room-temperature resin
  4. Mix slowly and carefully
  5. Coat/seal any embedded or porous materials before the main pour
  6. Use a toothpick in corners to free bubbles
  7. Use a heat gun or other heat source to pop surface bubbles
  8. Check back before the resin gets too hard to see if there are any new bubbles

1. Use the right type of resin

To start, you’ll need to choose the right type of resin for your application. There are two types of resin: casting (for volume) and coating (meant to stick to a surface and form a film over it, sometimes also called “Doming” resin). You’ll get the best results using the right type for your project. To find out if the resin is for casting or coating, the product description should tell you its intended use. For casting, I recommend EcoPoxy FlowCast for larger pours (i.e. river tables) and Entropy Resins CCF for smaller pours (i.e. small silicone molds).

There are also fast-cure and slow-cure resins, described more below. Slow-cure resins are generally thinner in consistency and allow bubbles to escape more easily and quickly. Choose slow-cure if you’re working with porous materials. EcoPoxy FlowCast is slow-cure and Entropy Resins also makes slow-cure casting and coating resins.

2. Use high-quality resin

Unfortunately, cheaper/lower-quality resins are more prone to air bubbles than higher-quality products. For this reason, I switched to higher-quality resin and now I’m not going back. For casting, I recommend EcoPoxy FlowCast for slow cures (72 hr) and Entropy Resins CCF for fast cures (24 hr). Both of these options are bio-based and more eco-friendly than most resins on the market, so you can also feel good about that.

3. Cast in a warm room with room-temperature resin

As resin gets warmer, it gets thinner in consistency. Resin that is thinner lets air bubbles escape more easily. That is why cold resin/a cold casting environment will lead to more bubbles. Some websites recommend putting your resin containers in a warm water bath — I’ve never needed to do this, but it may help if you live in a colder climate.

4. Mix slowly and carefully

Mix the parts of the resin together slowly and carefully, keeping in mind that certain motions, like scooping from top to bottom, can introduce bubbles. Stir clockwise or counter-clockwise, nothing fancy is needed. It will probably take longer than you want it to, but it’ll be worth it!

5. Coat/seal any embedded or porous materials before the main pour

If you’re embedding materials in your resin, you’ll want to coat them in resin before pouring resin over them. This is easiest by dipping the object and/or using a small brush to cover the surface in resin.

If the resin will be in contact with wood or another porous material, seal the contact area of the porous material before the main pour, otherwise resin will slowly seep into the pores and air bubbles will escape. To seal the porous material, use a small brush and a small amount of resin and brush it onto/into the porous surface. Allow this thin layer to dry before proceeding with your main pour. To further ensure minimal bubbles with porous materials, use a slow-cure resin for the main pour even if you have sealed the material.

6. Use a toothpick in corners to free bubbles

If you’re using a mold with sharp corners, bubbles may form in the corners of the mold. Use a toothpick or skewer to free these bubbles from the surface of the mold so that they rise to the surface, and then proceed to the next step once you get them all.

7. Use a heat gun or other heat source to pop surface bubbles

Heat will cause the resin to thin and pop any surface bubbles. For this step, you can use a heat gun, butane torch, or even a lighter (though not the best option), but be careful — heat in one spot for too long can damage the resin and prevent it from curing correctly. Only apply heat for the amount of time it takes to pop the bubble. I prefer to use a butane torch from several inches away and wave it slowly and evenly across any bubbles. Also, don’t inhale the fumes, even if you’re bored!

8. Check back before the resin gets too hard to see if there are any new bubbles

After performing all these steps, you may not be finished — sometimes bubbles like to come up later. I recommend coming back and repeating the previous step before the resin is fully hardened, which will depend on the cure time of your resin. For porous materials, I have come back and popped bubbles several times before they were all gone.

Other thoughts

Following these steps, you should be able to get rid of bubbles in resin, assuming you’re mixing thoroughly and with the correct proportions. My past several pours have had no visible bubbles and it feels so good to be finally rid of them!

Once again, I recommend EcoPoxy FlowCast for larger slow-cure pours (i.e. river tables) and Entropy Resins CCF for smaller fast-cure pours (i.e. small silicone molds). All of these options are less toxic than most other resins on the market. The first two options are bio-based and their companies are eco-conscious, which helps to offset some of the waste produced by this medium. EcoPoxy is food-safe when cured.

Some people recommend using a pressure pot to ensure all bubbles are gone — I don’t see the need for this if you follow the steps above. Some also recommend spraying rubbing alcohol on the surface to pop bubbles — I don’t recommend this because rubbing alcohol from the store is mixed with water, and water can prevent the proper curing of resin.

Good luck, and let me know if you still have issues!

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