How do you remove air bubbles from cured epoxy?
If your epoxy coating contains air bubbles but has already cured, you'll have limited options on how to remove them.
Air bubbles will form in your epoxy if the substrate used was porous. It's important to always add a seal coat before you pour mixed resin onto the surface.
Note: Some materials (e.g., certain woods) are incredibly porous and will require two or even three seal coats to fully seal. If you have a particularly porous wood or simply aren't sure, you can always apply a second or third seal coat before you continue to the next phase of the epoxy process.
If you haven't sealed the substrate properly, air bubbles can form after the epoxy has partially, even if you've already used a heat gun or propane torch to remove the typical air bubbles that appear early on with the flood coat.
You can usually fix surface level bubbles with some effort, but if the bubbles are deep, it becomes difficult.
For surface level bubbles:
- Sand lightly.
- Wipe with acetone. Wait 30 minutes for it to evaporate.
- Apply a new seal coat to fill in the blemishes. Wait four to six hours.
- Apply a new flood coat.
For deep bubbles:
- Sand heavily, removing most of the flood coat until you've sanded out every bubble.
- Wipe with acetone. Wait 30 minutes for it evaporate.
- Apply a seal coat. Wait four to six hours.
- Apply another seal coat. Wait four to six hours again.
- Apply a new flood coat.
Caution: We recommend two seal coats to be sure that it won't happen again.
See the photos below for examples of the air bubble issue:
