Microbubbles in epoxy resin? No thanks!
We can all agree that microbubbles are the enemy, but there are a few steps that you can take to minimize and even eliminate microbubbles entirely!
Step 1. Pick the Right Product
There are a lot of different epoxy resin systems available, many of which are made to do different things. Coating systems won't always perform well in molds, and casting systems don't always dry if applied too thin.
There is also varying levels of viscosity (thickness) that effects the ability for air to naturally release. Thinner formulas cause less resistance for air to rise, while thicker formulas may mean that air rises extremely slowly. However, this doesn't mean that thick epoxy resins should not be used, you will just need to follow the additional methods below to help remove air from the coating.
Last, the working time of the system will come into play. A short working time means air won't have time to rise, while long working times allow sufficient time for air to surface and release.
Review the technical data for accurate product information.
Three different coating systems:
Step 2. Warm Up the Two Components Before Mixing
The easiest way to minimize trapped air in the mixture and your final project is by both the resin and hardener being warm before mixing. Warming the components prior to mixing in a hot water bath for 15 minutes or in front of a space heater will drastically change the viscosity (thickness) of the components. Thinner liquid = less bubbles, and the bubbles that are in the mixture will more easily rise to the surface. An increase of 10-15° can make a significant difference in the thickness of the epoxy resin mixture.
It is worth noting that warming up the epoxy resin mixture will shorten the working time and that this tip isn't always ideal for every system, but in most cases warming the epoxy resin components up to 75-85F will significantly lower the amount of air that is introduced when mixing.
Step 3. Mix Slowly and Thoroughly
When you begin to mix the two components together you will inevitably introduce air into the mixture. Stirring quickly will add excessive air into the mixture, but stirring slowly will do the opposite. You can also expirement with different stirring utensils such as popsicle sticks, silicone stir sticks, spatulas, round ball stir sticks, and even metal stir sticks. While the difference may be minimal, you may prefer one over the other.
Step 4. Warm Surface + Warm Environment
Temperature plays one of the biggest roles with epoxy resin curing and air release. Keeping your environment warm (75°F-80°F) is ideal for room temperature curing systems. This includes the surface you will be applying epoxy resin to.
Colder temperatures will cause the epoxy resin to be thicker and can slow or even stunt the curing process.
Step 5. Apply, Wait, Torch, Repeat
After applying the epoxy resin coating you will want to apply heat to the surface to help air escape. Before you run and grab your propane torch, let the coating sit for a few minutes to allow air to naturally start to rise. After the few minutes have passed quickly sweep over the surface with your torch or heat gun to help that air release. You will notice a significant difference between immediately heating the surface and allowing a few minutes before heating. You can repeat this process an additional time if necessary, but be sure that it falls within the working time of the product (listed in the Technical Data section of the product page).
By following our steps above you should be able to achieve an incredible bubble-free finish.