How do I Get Bubbles Out of Resin?
Updated: Jun 23
I often get asked how I manage to get the bubbles out of in my resin art, what's my trick? I'm no expert, in fact I would question anyone who said they were! Resin is a great medium to work with, and when using it with dye's, mica's and alcohol ink you can eliminate the majority of bubbles with heat. It gets trickier when trying to embed items into clear resin. My success has been hard won, between a lot of practice, looking at others tips, and testing those techniques in different kinds of resin. What I found however was consistent techniques can produce inconsistent results across brands. Confused? Don't be! I'll share my best tips below on how, when and why each tip seems to work to. I hope it helps you in creating your own beautiful works of art!
For All Resin use:
Definitely read the manufacturer's instructions before you begin. I originally thought all Resin worked pretty much the same, that what techniques worked with one brand would certainly work with another.. definitely not true. For example one brand will want you to work with your Resin at room temperature, another will ask you to sit the Resin Part A bottle in a hot water bath up to 170 degrees F for 3 minutes but warn you to never warm up the Part B Hardener bottle, and yet another brand will want you to warm up both bottles in hot 'tap' water only for 5 to 10 minutes.... Crazy right? So even if it feels boring and redundant, I now read everything the manufacturer advises on using their brand of resin, both the instructions and troubleshooting tips, and it's saved me from a lot of headaches and failed art!
What seems to be universal in using resin:
Make sure you work with your resin in a warm environment ( 75-85F or 24-30C is usually advised as the best working temperature, but check your Resin's instructions to be sure ). I make sure I've set my thermostat a few hours before I plan to work, or that the outside temperature forecast is within the recommended range. If the resin is too cold it will not mix well and you could see: Cloudy resin, Resin with areas that never harden, Sticky Resin spots, etc.
Buy specific resin for the molds you are using, the manufacturer's instructions will advise which projects their resin is best used for, whether it's for silicone molds, plastic molds, etc.
Stir to mix your resin slowly.. very, very slowly.. this prevents you from building up a lot of bubbles.
Use the 3 to 4 Cup & 3 Mix & 2 Stir Stick method, seems like extra work but if you are new to resin this is the safest way to make sure that the resin you pour is totally mixed. Cup 1 & 2 are for measuring & your first &/or second mixings:
Cup 1 is for Part A, Cup 2 for Part B
Pour B into A & stir slowly scraping the sides, bottom & occasionally rubbing of your stir stick along the top edge to get that resin into the mix (I do this for 2 minutes). If the amounts of resin you are mixing are too much to fit into Cup 1, then use a larger Cup 3 to do this.
Pour Cup 1 back into Cup 2 & repeat the stir (or if using Cup 3 mix for 3 to 4 minutes instead)
Pour this into a Clean Cup but do NOT SCRAPE the sides, bottom or stir stick (Cup 3 or 4 per above) & use a new stir stick, mix for 2 minutes, scraping the sides, bottom & the new stir stick.
Pour into your mold or into cups to add color, it is safe to scrap every last drop. (Had you not moved your mix into a clean cup and then scraped the sides to get every last drop you risk incorporating unmixed resin which will not cure, could leave cloudy or sticky spots, etc.).
Getting your finished item out of the Mold & Extending the life of your Mold: Use a mold release agent, I can't emphasize this enough, without it you are risking having your Resin Art & Mold ruined when it fuses to your mold. Then you either throw out the art, or try to save it, taking away precious hours of your time. The mold is now unusable and you've lost money & time.
Using Mold Release Agents: There are two basic types that I've seen: Spray liquid & Aerosol. I use the Aerosol type so I can't advise on the spray type. After I have sprayed the molds with a Aerosol Release Agent I do not touch the sprayed parts of the mold again because if I do I am smearing and removing the release agent. I also make sure I only put a light spray as I don’t want big drops of release agent in the mold. If I make a mistake and overspray I wipe all of it out and start over. I then place my molds where I’m going to pour them.
Mold Release Agents: There are many brands of release agent available, you do need to make sure that the brand you choose is going to work with your type of mold and Resin. I love using Stoner E-236 Urethan Mold Release. It has a very fine misty Aerosol spray that dries very quickly vs others that have to sit for a hour before you can use them. It has worked with every brand of Resin I've tried so far. Some Resin brands have their own release agent, I'm a firm believer that if you are just starting out you will likely have the best results from using items formulated by a manufacturer to work together. For example: Environmental Technology makes Easy Cast Resin and Castin Craft's 33900 Mold Release and Conditioner, both are formulated to work well together, be sure to follow the instructions they provide.
Mold specific tips:
Pour the resin into the mold quickly after it's stirred so that it can De-Gas... Resin that has been formulated to self de-gas the bubbles will do so only while it is in it's most liquid form, once it begins to thicken it's more difficult for the bubbles to rise to the top and release. If you are doing a deep mold you will need to pour it in layers drying in between, most Resin recommends 1/4 to 3/8 inch max.
Pour slowly at a low angle close to what you are pouring into.. the lower you pour the fewer bubbles you will add.
I wait 5 to 10 minutes for the bubbles to rise on their own. During this time I take a large toothpick or a long wooden skewer to slowly go around the edges and inside corners of my molds to push any trapped air up. After I’ve waited a few minutes I use heat to remove the bubbles. You can use a blow torch however that often overheats the resin or the mold so I use a heat gun or a mini heat gun with a low air setting (so I don't make waves or move objects), keeping it 6 to 10 inches from the resin and I never point it at the mold directly.
I will redo this 5 times every 5 minutes for each mold as bubbles will continue to rise until the resin has started to cure, I prefer to work with Resins that have a minimum of 30 minutes working time. I will still miss some bubbles but this seems to get most out.
Adding embedded objects: If you’re adding embedded objects (flowers, charms, foil, etc.. you would do so now if they will float. (Note:If they’re heavy and are going to sync you need to do a thin layer & let it dry for 5 to 8 hours, or overnight, then add your objects with the next layer, then another layer on top to fully embed them).
When I add mine I do this:
Flat objects like flowers, I use my wooden skewer to press the item down into the resin from one end of it to the other, essentially pushing out any trapped air bubbles from underneath.
Non flat objects, I will often use my wooden skewer to turn them over a few times, if it is 3 dimensional flower I will push on it to force any bubbles out from within the petals, etc.
Some of the Great resins for Silicone Molds that I've had success with:
Brands I do not recommend & Why:
Puduo: Epoxy-Resin-Crystal-Clear-Art 1 Gallon Kit for Coating, Casting, Resin Art, Jewelry, Tabletop, Bar Top, Live Edge Tables, Fast Curing 2 Part Epoxy Casting Resin Kit... Very inconsistent results, including the cloudiness you see in the picture above, even after following the manufactures directions, in four different tests with 12 molded items half came out cloudy, even within the same mix & pour. I will now only use the remaining resin supplies I have of this brand on pours where I'm using Mica's and cloudiness is not a concern.
Should I use a Degassing Chamber? I have one, I've tested it many times with no success, so I personally can't recommend it. While it helped to release the larger bubbles, it also created thousands of micro bubbles, seemed to cause the resin to heat up and harden much faster too, making it impossible for the micro bubbles to release. You also need two containers that will nest together as the resin is degassed it rises to the top of the container and will overflow .. bottom line for me is "No I do not recommend one". I have more success with a toothpick & heat.
Cover your curing art so after you pour so no new dust gets on them. I just use those metal tin trays you can get at the grocery store super cheap and I reuse those over and over again. You can use anything you have on hand, a cardboard box works once you've made sure it has no dust or dirt in it. I always store my covers upside down so extra dust doesn’t get into them. I always bang them a few times to knock any dust out and hit them with a blow dryer for a second to blow out any dust before using each time.
Make sure your work surface is totally flat, if it is not your resin is going to flatten itself and dry on an angle. That's a great technique for layering resin colors, but only if that is what you wanted to do.
I find that the best way to determine how to work with a specific Brand of Resin is to experiment with it on items that you’re ‘OK’ with destroying! The worst thing for me is to try out a new Resin on an item where I really need it to be perfect, maybe I only have a limited number of flowers to embed, or it's a gift and I only have just enough time to do it once and then it fails and I've got no other backup plan.
I hope these tips have been helpful in your pursuit of creating art and that you make something beautiful today! If you’re looking for any of the supplies mentioned in this article here is a link to make it easy for you to find them in one place. This is an affiliate link & I receive a small percentage back which helps pay for this website & blog.
If you would like to purchase any of my resin art I sell it in my shop on Etsy: https://www.etsy.com/shop/PaintingArtsNCrafts.