How to Get Rid of Microbubbles in Epoxy Resin

Microbubbles? 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:

Liquid Art Elite
Thin Formula
Longest working time (~60 Min.)

Liquid Art
Medium Thickness
Long working time (~45 Min.)

Liquid Stone
Thick Formula
Short working time (~30 Min.)

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.

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 = Profit?

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).

FINAL RESULT

By following our steps above you should be able to achieve an incredible bubble-free finish.


Other articles:

The Best Epoxy Resin for Tumblers

Looking for the best epoxy resin for tumblers?

Finding the perfect epoxy resin system can be intimidating. From thick to thin, fast drying to extended working times, KSRESIN offers multiple options that will suit your needs for the best tumbler epoxy resin.

⬇️     Read the article below to learn more!     ⬇️

Best Selling Epoxy Resin for Tumblers

Liquid Art Ultra UV

Liquidy Split Ultra UV Fast Dry

Let's start by discussing a few technical aspects that will come into play when picking an epoxy resin.

A few things to consider:

  • Is the epoxy resin thick or thin?
  • Is the epoxy resin clear or colored?
  • Does the epoxy resin smell?
  • Will the epoxy resin yellow over time?
  • What is the working time of the product?

Left - Epoxy Resin 10,000 cP

Right - Water 1 cP

1. Viscosity (Thickness)

Viscosity is a term that refers to the thickness of the epoxy resin (or other fluid). Each component has a viscosity level that is generally measured in centipoise (cP). The higher the viscosity/cP, the thicker the component or mixture will be. The lower the viscosity/cP, the thinner the component or mixture will be.

Viscosity is very important to understand as air naturally rises to the surface because the liquid is heavier than the air. When you have a mixture with a low viscosity, air will more easily rise to the surface. On the contrary, a high viscosity means that the air will rise slower to the surface.

When using a high viscosity system it is important to stir slowly to minimize the amount of air that is introduced into the mixture. You can also lower the viscosity of epoxy resin by warming the components in a hot water bath prior to mixing the components together (temperature dependence of viscosity).


2. Color

A clear epoxy resin is crucial for making a tumbler. A lot of coating systems that are marketed towards tumbler makers are clear, though some systems have masking agents added to them that will turn the resin blue to hide their natural yellow color, some products such as our Ultra UV line will have a slight yellow resin hue, and some even have a brown hue because of the raw materials chosen for the formula. Does that mean that they will be blue, yellow, or brown once dried? Not necessarily.

Our Ultra UV products appear with a slight yellow hue in them from the UV additives that are added to our products (more on that later), but the yellow hue only shows up when the epoxy resin is in a large mass such as a half gallon container. Once the product is applied as a thin coating, such as on a tumbler, it will be completely clear. Okay, what about the blue? We've personally chosen to not use blue masking agents in our epoxy resin because when comparing the two on a white substrate the slight blue hue is more noticeable.


3. Volatile Organic Compounds (VOC) / Odor

Volatile Organic Compounds (VOCs) are gases that are released from some chemicals and play a big role in odor. High levels of VOC can cause irritation and nausea (among other things), so when choosing a tumbler epoxy you want to pick something with extremely low VOC content. All KSRESIN products are formulated to meet "No VOC / Zero VOC" compliance for coatings, which means they contain less than 5 grams per liter. Be sure to pick a coating epoxy resin with Low or No VOC.


4. Ultraviolet (UV) Resistance

Unfortunately it is inevitable that epoxy resin will eventually yellow/amber from UV exposure. However, we add basic UV inhibitors into ALL of our products to extend the amount of time it takes before the product shows yellowing from UV exposure AND we also offer our Ultra UV and Elite product lines which contain industry leading hindered amine light stabilizers (HALS) plus our UV inhibitors to ensure that our products outperform the competition as well as show significant improvement over our basic UV inhibitors.

While other epoxy resin suppliers claim they have UV resistance, our products are frequently tested in a QUV Accelerated Weathering Tester to ensure that the UV additives perform properly and better than our competitors. A QUV Accelerated Weathering Tester reproduces a spectrum of UV light that the sun exposes us to so that we can analyze how long our products will last in comparison to other available coating systems. While we use the industry standard of testing, you can also do these tests at home to compare different brand's UV resistance.

If you are selling your artwork, it is important to use a product that will last and has excellent UV resistance.


5. Working Time

Working time is a term that we use to specify how long the epoxy resin will be workable before it begins to thicken. As the epoxy resin enters the gel phase, the viscosity will drastically increase and it will be much more challenging to spread or move around.

For those who are new to coating tumblers or who like to take their time, we suggest using a product with a long working time.

For those who are experienced and like to finish layers fast, find a product with a short working time.


Let’s compare a few KSRESIN products so that we can figure out which product will work best for you.

Liquid Art Coating Epoxy Resin

Liquid Art

Viscosity - 4,600 cP
Clarity - Clear
VOC
- No VOC
UV Resistance - Basic UV Additives
Working time - 45 Minutes

Liquid Art Ultra UV

Viscosity - 4,600 cP
Clarity - Clear
VOC
- No VOC
UV Resistance - Long Lasting UV Additives
Working time - 45 Minutes

Liquid Art Elite

Viscosity - 2,700 cP
Clarity - Clear
VOC
- No VOC
UV Resistance - Long Lasting UV Additives
Working time - 60+ Minutes

Liquid Art is our top selling coating epoxy resin, and is most commonly used for coating tumblers. We have three variants of Liquid Art that are important to review.

 

Liquid Art (regular entry-level) - This system is a medium thickness formula with a viscosity of 4,600 cP so it is easy to mix and apply. It has a long working time of 45 minutes, basic UV inhibitors to help resist yellowing from UV exposure, it meets criteria to be considered Low / No VOC, and it is extremely clear without added masking agents.

 

Liquid Art Ultra UV (improved UV resistance) - This system is nearly identical to Liquid Art, though it contains our Ultra UV additives that have proven to resist ultraviolet degradation by up to TEN times longer. It is also a medium viscosity epoxy resin with a viscosity of 4,600 cP, has a long working time of 45 minutes, is Low / No VOC, and it is extremely clear with a slight yellow hue from UV additives (this yellow hue will only be noticeable in the containers, once applied it will be completely clear).

 

Liquid Art Elite - This system was developed to improve the air release, scratch resistance, temperature resistance, and durability over Liquid Art and Liquid Art Ultra UV. It is a lower viscosity epoxy resin with a viscosity of 2,700 cP, has an extended working time of 60+ minutes, is Low / No VOC, a high temperature resistance, and it is our clearest coating epoxy resin system.


Okay, we’ve looked at three products in the Liquid Art product line and discussed their key differences. What about something for the more experienced tumbler makers that want to finish projects faster?

Liquidy Split Fast Dry Coating Epoxy Resin

Liquidy Split Fast Dry

Viscosity - 6,900 cP
Clarity - Clear once dried
VOC
- No VOC
UV Resistance - Basic UV Additives
Working time - 15 Minutes

Liquidy Split Ultra UV Fast Dry

Viscosity - 6,900 cP
Clarity - Clear once dried
VOC
- No VOC
UV Resistance - Long Lasting UV Additives
Working time - 15 Minutes

Liquidy Split is our increasingly popular fast drying epoxy resin system that will dry in a 1/3rd of the time that Liquid Art dries. What does this mean? More coats of epoxy resin on your tumbler in less time. You can finish a cup in one day rather than one week! This product comes in two variants:

 

Liquidy Split - This system is thicker than our Liquid Art product at 6,900 cP, but it is still easy to mix and easy to get rid of any introduced air. It has a short working time of 15 minutes (you must work quickly), basic UV inhibitors added for anti-yellowing, is Low / No VOC, and has a very slight yellow hue from the raw materials used in the formula (this yellow is more noticeable in the containers, once applied it will be clear).

 

Liquidy Split Ultra UV - This system is nearly identical to Liquidy Split with the addition of our Ultra UV additives to prolong the UV resistance by up to TEN times longer than the regular formula! It has the same short working time of 15 minutes, Low / No VOC, and a slight yellow hue from the raw materials used in the formula (this yellow is more noticeable in the containers, once applied it will be clear).

Still not sure which epoxy resin is best for tumblers? Feel free to reach out to support@ksresin.com and we can help!


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How to Get Rid of Microbubbles in Epoxy Resin


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