Why Epoxy Resin Gets Bubbles and How to Reduce Them
Bubbles are one of the most common frustrations in epoxy projects. They can show up in river tables, mould pours, void fills, top coats, and smaller serving board projects, even when everything else seems to be going well.
The good news is that epoxy bubbles usually happen for a reason. Once you understand the most common causes, it gets much easier to reduce them and get cleaner-looking results on future pours.
Quick Take
- Bubbles usually come from air trapped in the wood, introduced during mixing, or created during the pour.
- Porous wood and live edge material can release air into the epoxy.
- Mixing too aggressively can add extra air to the resin.
- Wrong product choice can make bubbling harder to control.
- Good prep and technique can make a big difference in reducing bubbles.
Why Does Epoxy Get Bubbles?
Epoxy bubbles are usually caused by trapped air, mixing technique, product mismatch, or environmental conditions. Sometimes the bubbles are tiny and cosmetic. Other times they become a major problem that affects the final look of the project.
In woodworking, bubbles often happen because the wood itself contains air in pores, cracks, knots, checks, or live edge areas. When epoxy is poured over or into these areas, that trapped air can escape into the resin.
The Most Common Causes of Epoxy Bubbles
1. Air Coming Out of the Wood
Wood is one of the biggest bubble sources in epoxy projects. Live edge slabs, cracks, voids, knots, and porous grain can all release air into the epoxy during a pour.
This is especially common in river tables, serving boards, and slab projects where the epoxy is flowing into natural imperfections or uneven edges.
2. Mixing the Epoxy Too Aggressively
Mixing epoxy too fast or too aggressively can whip extra air into the resin. That trapped air can then show up as bubbles in the finished project.
Even if the epoxy eventually cures properly, poor mixing technique can make the project look much worse than it should.
3. Pouring Too Fast or Too Carelessly
Pouring technique also matters. A rushed or careless pour can trap air in corners, voids, and tight spots, especially when you are working with uneven wood shapes or mould edges.
4. Using the Wrong Epoxy for the Project
Not all epoxy is designed for the same use. If the epoxy is not suited to the pour depth or application, bubbling can become harder to control.
Matching the product to the project is one of the simplest ways to improve results.
5. Temperature and Shop Conditions
Shop temperature and project conditions can affect how epoxy flows and how air behaves in the pour. Poor conditions can make bubble issues worse, especially when combined with wood that still contains a lot of trapped air.
The Main Idea
Most epoxy bubbles come from either the wood, the mixing process, the pour technique, or using the wrong epoxy for the job.
How to Reduce Bubbles in Epoxy
Seal Problem Areas When Needed
If the wood has open grain, knots, cracks, or porous live edge areas, it can help to deal with those areas carefully before the main pour. That can reduce the amount of air escaping into the epoxy during the project.
Mix Carefully
Mix thoroughly, but do not mix in a way that whips unnecessary air into the resin. Clean, controlled mixing usually gives better visual results than rushing through the step.
Use the Right Epoxy
A deep pour project should use an epoxy suited for deeper casting. A surface coat should use a top coat epoxy. Product mismatch is one of the most avoidable causes of poor epoxy results.
Pour with More Control
Slower, more controlled pouring often reduces air entrapment compared with rushing the pour into tight areas or letting the resin fall awkwardly into corners and voids.
Work in Better Conditions
Good prep, clean surfaces, and stable project conditions all help reduce the chances of bubble problems.
Projects Where Bubbles Commonly Show Up
River Tables
River tables often combine live edge wood, thicker pours, and natural voids, which makes them one of the most common places for epoxy bubbles to show up.
Void Fills
Cracks, knots, and checks can trap air and release it into the epoxy while the project is curing.
Charcuterie Boards and Serving Boards
Smaller projects can still bubble, especially when decorative resin is poured into irregular areas of the wood.
Top Coat Applications
Even top coats can bubble if the surface prep, mixing, or conditions are not right.
Helpful Products for Cleaner Epoxy Results
- EcoPoxy FlowCast
- EcoPoxy FlowCast SPR
- EcoPoxy UVPoxy
- Shop All Resin + Epoxy
- Liquid Pigments
- Moulds and Forms
Helpful Related Guides
- Epoxy Resin Guide for Beginners
- Epoxy for Woodworking
- Deep Pour vs. Top Coat Epoxy
- How to Mix Epoxy Resin
- How Much Epoxy Do I Need
- Why Epoxy Won't Cure
Common Mistakes That Make Bubbles Worse
- Skipping prep on porous or irregular wood
- Mixing too aggressively
- Using the wrong epoxy for the application
- Pouring too quickly into voids and corners
- Ignoring the project conditions
Frequently Asked Questions
Why does epoxy get bubbles?
Epoxy gets bubbles because of trapped air in the wood, extra air introduced during mixing, rushed pouring, the wrong product choice, or poor environmental conditions.
How do I stop bubbles in epoxy resin?
You can reduce bubbles by preparing the wood carefully, mixing in a controlled way, pouring more slowly, and using the right epoxy for the project.
Do bubbles in epoxy come from the wood?
Yes, they often do. Wood can trap air in pores, cracks, knots, and live edge areas that later escape into the epoxy.
Does mixing epoxy too fast create bubbles?
Yes. Aggressive mixing can add unnecessary air into the resin, which can then show up as visible bubbles.
Can the wrong epoxy cause bubbles?
Yes. Using an epoxy that is not designed for the application or pour depth can make bubble problems harder to manage.
Shop Epoxy for Woodworking Projects
Browse epoxy resin, pigments, moulds, and project supplies for river tables, void fills, top coats, serving boards, and other epoxy woodworking projects.
Shop Epoxy + Resin Products
