Collection: Primaloc Epoxy Blog

A silicone mold with two of the reservoirs filled with colorful epoxy resin.

Primaloc Guides: Resin Mold Cleaning and Storing

Cleaning up after an epoxy project isn't particularly exciting, but it's nonetheless important. Once the epoxy has cured, you'll likely want to move it to a convenient location so you can then dispose of any trash (such as one-time-use items) appropriately.

Some items, however, are reusable, and this includes resin molds.

Using resin molds is common in the creation of epoxy resin arts-and-crafts. These molds are handy because the silicone materials they're typically made with are unable to bond with the epoxy resin, allowing the epoxy to be released easily after it has finished curing.

Knowing how to take care of your resin molds is important for keeping them ready to be used in your epoxy projects as needed. In this article, we'll explain how to clean resin molds before and after use, as well as how to store them to keep them clean and free of dust and other particles or residues.

How to Clean Resin Molds Properly

Cleaning your resin molds is rather straightforward, and most of the information in this guide may seem a bit obvious. Still, being sure to handle things like this properly is how you achieve ideal results and avoid issues.

The first thing to keep in mind with resin molds is that they often look "clean" after the epoxy is removed from them. But even if they look that way, it's good to give them a proper washing before storing them away for future use.

A smooth surface free of even the tiniest debris will help ensure your epoxy projects turn out the way you want them to by preventing contaminants (e.g., dust) from entering the epoxy resin when it's poured in.

A smooth surface also keeps the epoxy from bonding with the silicone and makes it easy to remove.

There are three main phases to cleaning resin molds:

  • Preparatory Cleaning - An optional phase involving removal of loose debris from the mold to make it easier to wash.
  • Main Cleaning - The main phase involving water and soap/detergent to remove most or all potential contaminants.
  • Secondary Cleaning - An optional final phase which involves extra methods to remove particularly stubborn residue/debris such as resin remnants.
A tray of various sea-themed silicone molds.

Phase #1: Preparatory Cleaning

You'll begin the process with a little bit prep cleaning. There are two very similar techniques we use to accomplish this: one involving adhesive tape, and another involving adhesive putty.

Here's what you do:

  1. Press a small amount of adhesive putty or the sticky side of some adhesive tape into the surface of your mold.
  2. Pull it back. Anything loose on the mold should stick to the tape/putty and be separated from the mold surface.
  3. Repeat until you've gone over the whole surface. Once you're finished, it's time to move onto the next phase.

Phase #2: Main Cleaning

The main cleaning phase is fairly unoriginal. Just as you would clean debris or resin off your skin, you can also away debris and resin from your molds, with hot, soapy water.

Note: It's not a bad idea to wear some cleaning gloves while washing your molds. Soapy hot water can dry your skin out quickly, and depending on what which detergent you use, it can also cause mild irritation.

Here's what you do:

  1. Fill a bucket or container with hot water. The reservoir needs to be large enough to fully immerse your mold. Some faucets can't deliver hot water properly; in such cases, you can microwave some water until it's hot (but not enough to burn your skin).

  2. Mix in some dish detergent with grease-removing properties (that's most of them). Probably a teaspoon minimum. You can churn the water a little to turn it into a solution; you'll know it's working if suds form.

  3. Fully immerse your mold into the solution and allow it to stay there for about 30 to 60 minutes. The cleaning solution will gradually work its way into any residue or grime present and weaken the bonds.

  4. Life out the mold and put a couple drops of detergent on your fingers or a nonabrasive sponge. Then rub the mold gently to dislodge everything on there. Make sure you reach the any grooves and corners.

  5. Let your mold(s) air-dry. The amount of time needed will vary based on temperature and humidity levels in the room. We do this because towels and other drying options have a tendency to leave behind fibers or other contaminants, thus defeating the purpose of the cleaning.

    Note: A really good lint-free cloth can be used to dry them. This can be useful for areas with hard water, which tends to leave behind mineral sediment when it evaporates.

Phase #3: Secondary Cleaning

For stubborn residue, which is a rare case, there is one other technique you can try.

If hot soapy water wasn't adequate, you can also try placing your molds in the freezer for a bit. This will weaken the bond between them and many types of stubborn residues that may still be present.

Here's what you do:

  1. Put your resin molds in a freezer. You'll leave them here for a while.

  2. Wait about 1 hour, which should weaken the bond of any residues on the silicone. Take the molds out of the freezer.

  3. Gently use your fingers to separate the residue/grime from the surface of the mold. You push it, peel it, carefully scrape it away with a plastic utensil—any of those things can work depending on what you're dealing with.

  4. Finally, you can rinse the molds off and let them air-dry (or manually dry them with your lint-free cloth).

Other Considerations

Though these methods will work in most cases, sometimes a mold just simply gets damage. The damage may not even be noticeable, but it can affect the bonding of epoxy resin.

For instance, if there are microscopic holes in the silicone's otherwise smooth surface, resin can seep into those when you pour it in and bond to the resin in that way.

If your resin molds get damaged, you're probably better off just replacing them.

A bunch of different-sized clear plastic containers resting on a light blue surface.

Storing Your Resin Molds

We have a few suggestions for how to store your molds so that they stay clean and ready to use:

  • Keep them in a cool environment. Direct sunlight and high heat can weaken or even damage silicone over time.
  • Store them in a sealable plastic bags or a clean air-tight container. This will prevent dust from settling on them. If you use bags, you can press the air out after the molds are inside, then seal them.
  • Ensure the mold keeps its shape by not putting stuff on them or letting them flop about if they're flexible. These molds tend to be tough, but they can become misshapen if enough pressure is applied for a long enough period.

Primaloc Epoxy: Premium Epoxy for Premium Results

When it comes to epoxy resin, Primaloc Epoxy gets the job done. Our epoxy resin is premium-grade, with high performance in every category, and it excels as a material for the types of resin art involving silicone molds.

Epoxy resin can be beautiful, strong, and long-lasting—which is why you shouldn't compromise on quality. With Primaloc Epoxy Resin, you get the ultimate finish in durability and visual appeal.

Protect your surfaces by giving them a rock-solid epoxy finish. Choose strong. Choose reliable. Choose Primaloc.


Previous Primaloc Answers: Epoxy Resin FAQs
Next Primaloc Epoxy Basics: How to Mix Epoxy Resin