Among the many characteristics of resin that make it popular for crafting, its aesthetic appeal takes the cup. Therefore, most people get started with resin, aiming to create beautiful, flawless glass-like pieces.
Unfortunately, though, one issue often thwarts such expectations – pesky bubbles. Resin crafters will unequivocally agree that bubbles are a nightmare.
When not acted upon on time, the bubbles stay trapped inside the resin as it hardens. This means the end result is flawed, which is unfortunate, especially after spending so much time, effort, and money.
So then, how do you remove bubbles from resin? You can remove bubbles from resin using heat. A torch, lighter, or heat gun can be used for that purpose. However, you may have to go over the surface of your project more than once.
Keep reading to learn about the various ways of removing bubbles from resin. We also provide tips to help you prevent or minimize the formation of bubbles.
What Causes Micro Bubbles In Resin And How To Prevent Them
Before trying to fix a problem, it is wise to find out what causes it to avoid a similar occurrence in the future. So, what causes microbubbles in resin?
Cold resin or a low surrounding temperature is the primary cause of microbubbles in resin.
Microbubbles give resin a cloudy and frothy appearance. These are practically impossible to get rid of if you do not do something about them way ahead of time. Warmth helps resin be clearer, thinner, and easier to pour. In addition, it lowers the surface tension.
When there’s a significant temperature change, surface tension increases, causing bubble formation. Therefore, warmth is your ally when working with resin.
Since the reaction between resin and hardener produces heat, starting warm means the temperature is steady. When there is no drastic change, surface tension remains low.
Raising the temperature of your 2 part epoxy before mixing dramatically lowers the formation of minuscule bubbles.
You can put part A (resin) and part B (hardener) in a warm water bath to warm them up. Alternatively, place them close to a space heater for a few minutes.
You can also warm the room and prewarm the molds in a microwave. Getting everything to about 75-78°F would be ideal. But the temperature difference is not the only culprit.
Air can get trapped inside the mold during the pour or while mixing the resin. That is why you must mix and pour resin skillfully to cut back on air being introduced into the resin.
If your mixing looks like you are whipping cream or whisking eggs, you are doing it wrong and only introducing more air into the resin. The best way to stir is by using a slow circular motion and occasionally scraping the sides.
Also, it is best practice to pour all around the edges of the mold, coating the walls first before filling the middle. Pour slowly and very close to the mold.
Finally, avoid wooden spoons for stirring your resin. Opt for a plastic or silicone spatula. The difference may seem small, but it counts.
Quality Of The Resin
If the consistency of the resin is too thick, you are in trouble. Less viscous resin is lighter, allowing air to move up and release freely. Thicker resin provides more resistance, barring air from surfacing quickly and preventing escape.
The same concept applies to your working time. Resin with a longer working duration provides the air more time to rise to the top than resin with a shorter working time.
Porous Or Breathable Inclusions
Inclusions that contain tiny air sacs, especially organic materials like leaves, flowers, wood, paper, and fabric, are a recipe for bubble formation. These spaces are filled with air.
The materials will off-gas, sending air bubbles into the resin. This may transpire in the late stages, sometimes even when the resin has already begun hardening, and hence are impossible to remove.
To avoid this, you can seal the inclusions prior to use. A sealant will bar the air from coming out.
If you’re pouring resin on a photo mount, ensure there is no air pocket beneath by uniformly distributing the adhesive. You can use a brayer to smooth out the print application.
Resin works optimally for thin surface applications. A maximum of an ⅛”, to be precise.
Anything thicker, and you’ll have bubbles cure into your creations. They’ll have a long way to travel up and may not make it to the surface in time to be released.
Therefore, if you want to cast something thicker than ideal, you should pour the resin in multiple layers. Allow ample time between layers, usually a few hours. That way, you can eliminate bubbles in every layer effectively.
How To Get Air Bubbles Out Of Resin
Bubbles are inevitable. Despite doing everything mentioned religiously, you’ll still get some, just not as bad as if you hadn’t mitigated the situation.
But that is nothing to agonize over. There are several easy methods you can take advantage of.
If you’d like a visual tutorial, take a look at this one from BuzzingFish. Otherwise, keep reading for step-by-step instructions for several methods..
Method 1: Removing Bubbles Using A Torch
A propane torch (we love this one available on Amazon) offers the simplest way to remove bubbles with just a few passes. But if your mold is silicone, opt for a heat gun instead, as the flame of a torch could damage it.
A heat gun is not as fast as a torch for extensive surfaces but will do for small crafts. You can also use a utility lighter.
- Step one, do nothing. We know this is not what you expected, but just trust the process. Allowing the resin to sit for at least 3 minutes gives it time to degas on its own, and the bubbles make their way to the surface where it will be much easier to pop.
- Once the bubbles reach the top of the resin, grab a propane torch and turn it on.
- Aiming at the resin, move a bit close and sweep over the surface quickly from side to side until you cover the entire area and see the bubbles disappear.
- You can repeat the process two more times, as long as the resin has cooled a bit and you are still within the working time.
- Do not overheat the resin, or else it won’t cure rock hard. Avoid lingering more than 2 seconds on the same spot.
Method 2: Removing Bubbles By Blowing
Bubbles that are very close to the surface can be removed by blowing. Blowing helps them pop.
You can blow over the surface by mouth or using a device like a hair blow dryer. For the stubborn bubbles, you can target them individually and, using a straw, blow them directly and watch them vanish.
Method 3: Physically Removing Bubbles From Resin
Blowing and heating have no impact on deep-seated and corner bubbles. It would be best if you first tried to prod them away from the edges to the center.
Toothpicks come in handy for the job. You can use one to just go in and try and pop the bubble physically.
If the bubble seems stubborn, you can swirl the toothpick to extract it or get it to push up, then eliminate it using heat or blowing.
Sometimes toothpicks can push the bubbles further down if you are not careful.
Method 4: Pressure Pot Or Vacuum Chamber
If you are doing resin projects professionally, you certainly should use a vacuum chamber or a pressure pot (like this one from California Air Tools on Amazon specifically designed for resin casting) to help clear bubbles.
These are helpful tools that resin businesses can invest in, as they do a fantastic job of banishing all the bubbles.
Vacuum chambers draw air out to create a vacuum. In the process, the air contained in the resin is forced out too, and the bubbles cease to exist.
Contrarily, pressure pots work by introducing air into the chamber such that the air pressure increases. As the air pressure builds up inside, the bubbles in the resin begin to shrink until they become invisible to the naked eye.
How To Remove Bubbles From Cured Resin
You might still find some noticeable bubbles in your resin after the complete cure. We understand how disheartening that can be, but all hope is not lost. You still have a chance to attain that crystal clarity you dream of by removing the flaws. So how do you do it?
- Using coarse sandpaper, sand down the surface through to the bubble to eliminate it. You are creating something for the resin to bite into at the same time. Your resin craft will turn uglier from all the scratching and scuffing but don’t worry; that’s temporary.
- Clean away the dust using a damp, lint-free rug or microfiber clothing. Be meticulous as possible, paying particular attention to any nooks and crannies.
- Carefully prepare a fresh batch of resin, applying all the tips to prevent bubbles.
- Repour the resin into a thin layer. It will settle in all the scratch marks you made earlier.
- Go over the surface with a torch to eliminate any bubbles, then let cure. Sit back and watch how the once scuffed surface turns out sparkly, clear, and beautiful.
That is basically how to remove bubbles from resin. Heating is the easiest and most common method that produces good results. However, you can use it in combination with blowing, a vacuum chamber, or a pressure pot.
The little things like avoiding chaotic mixing, prewarming your resin and molds, and thin pours go a long way to make the resin less bubbly.
While the discussed methods of bubble removal work for most craft resins, they don’t for all types of resin. Some epoxies are harder others have a very short work time; you have to experiment to find out what brand works best with which method.
Remember, all safety precautions must be adhered to when using high-risk devices like torches and pressure pots. A mask or respirator is also essential when mixing or sanding resin.
Happy crafting, and don’t let the bubbles ruin the fun.