Avoiding Bubbles In Epoxy Projects (Includes Process Videos)

Are you tired of constantly battling air bubbles in your epoxy projects? Whether you're an experienced epoxy maker or just starting your first project, dealing with bubbles can be very frustrating.

There’s a lot of confusing and often conflicting advice out there about how to prevent bubbles when working with wood (or other materials) and epoxy. Based on my extensive experience, I’m going to share three techniques that I’ve found significantly reduce bubble formation. Just to clarify, I’m not sponsored by any of the products I’m recommending—I’ve simply found them to work well through personal use.

1. Seal It

Preparation is crucial for epoxy and woodworking projects, and combating bubbles is no exception. If you don’t prep your wood (or other porous material), bubbles will keep forming until your epoxy sets, by which point it’s too late. That’s why you need to seal your wood beforehand. Many people use a “seal coat” of epoxy, which involves brushing on a thin layer and letting it partially cure before doing the full pour. While this method works relatively well, it’s not my favorite.

An epoxy table-making expert once recommended an alternative sealing agent, and it’s now my go-to. It’s a thinner, less viscous alternative to epoxy often used to stabilize rotted wood. This product: PC-Petrifier wood hardener, can be purchased online from Amazon, Home Depot, etc. It has a milky white color when applied but dries clear (unless you let it pool too much). I apply it generously with a disposable sponge brush, and then brush away any excess to avoid pools or streaks. This only matters if you intend to apply a clear epoxy coat directly over it; otherwise, it can be applied less carefully and sanded or covered with opaque epoxy later.

Another huge benefit of sealing, especially when using clear epoxy coats, is avoiding color bleed from sawdust. If you’ve ever tried to remove every speck of walnut dust from a piece of burl only to find your “clear” epoxy turns brown in spots, you’ll appreciate what I’m talking about. Below I've included an example video where I apply PC-Petrifier to a couple pieces of maple burl.

2. Vacuum It

To reduce bubbles, I recommend using a vacuum pump and chamber to bring your post-mixed epoxy to a vacuum and let it sit until the bubbles have dispersed (usually 5-30 min. depending on epoxy type, temperature, etc.). Mixing epoxy, especially with a drill attachment (my preferred method for saving time and effort), introduces a lot of bubbles into the mixture. This vacuum process generally removes 99% of the bubbles before pouring. For those who may be interested, here's a link to the vacuum pump kit that I use. I'm not affiliated or sponsored in any way, just have had good results with it so I figured I'd share. Below you'll find a quick example video of some epoxy being purged of bubbles via the vacuum method. 

3. Heat It (If Necessary)

If your prep work is thorough, you may not need to burst bubbles. Also, many quality epoxies (such as the one I recommend later) are formulated to help bubbles disperse on their own. However, if bubbles do appear and stubbornly refuse to disperse, you can use either a torch or a heat gun to get rid of them. I prefer a battery-operated heat gun because it avoids the hassle of dealing with cords near epoxy or changing fuel with a torch. A good strategy for picking a heat gun is to choose whatever brand you already use for other battery operated tools like your drill, so that you can utilize the same battery set. 

No matter which heating device you use, the technique is largely the same: Move the tool along the surface of your project, keeping it a few inches away, and direct the heat towards any bubbles you find. You should see the bubbles start to pop almost immediately. Be careful not to overheat the piece or focus the heat in one spot for too long(no more than a second or two), as this can cause the epoxy to flash cure and trap the the bubbles and/or ruin your epoxy. If the bubbles aren’t popping with the application of heat, or keep coming back continuously after 5+ minutes, it’s better to stop before causing more harm than good. Having to fix some bubbles later by sanding etc. (which may even disperse on there own given enough time) is better than causing a flash cure and completely ruining your epoxy. Below I've attached an example video showing the heat gun and technique I use. Keep in mind, the appropriate distance between the heat source and the epoxy, as well as the speed you move it, will vary depending on the tool you use. In my case it's a relatively low heat device, so I can get away with holding it pretty close.

Bonus Technique: Start with High-Quality Epoxy

Using a high-quality epoxy is a crucial first step. If bubbles are a primary concern, also consider using a deep pour epoxy. High-quality epoxy offers numerous benefits, such as producing fewer toxic fumes, being less likely to flash cure or overheat, and naturally expelling bubbles more effectively. I’m speaking from experience—I’ve spent thousands of dollars on epoxy and have learned not to waste my time with the cheap stuff.

Once you find a brand that consistently delivers good results, stick with it. Various brands (and even types/models within a brand) can behave very differently, so it’s best to avoid unnecessary complications. Among the various types of epoxy (deep pour, art casting, countertop, etc.), I’ve found that deep pour epoxy is the most forgiving when it comes to preventing bubbles. This is due to the longer set/cure times and lower viscosity. 

Here's a link to the epoxy company I use: Epodex. I'm not saying they are necessarily the best out there, but they are in fact the best I've tried, and I get consistently good results using their products. The same can't be said for many of the other brands I've tested. To be clear, I'm not sponsored by or have any incentive/influence to recommend this brand beyond my own experience and wanting to help others avoid issues. More specifically I use Epodex's "Deep Pour & Casting" variation for anything over 3/4 inches thick, or when I'm very concerned with bubbles e.g. when using significantly porous wood. For everything else I use their "Art Resin & Crafting" variation, especially when I want a cool pattern from an endothermic reaction (more on this in a future blog). 

I hope you have found this article helpful. If you have any questions don't hesitate to reach out, and happy crafting!