If you are wondering ‘Why is my resin hot?’, let me assure you that it is a perfectly normal occurrence. It can be a little concerning to feel your resin mixing cup warm up in your hands, but this should be expected. In order for a resin and hardener mixture to cure, an exothermic reaction takes place when the two liquids are combined producing heat, which allows the blend to solidify. However, there can be too much of a good thing and resin that gets too hot will cure in unexpected ways.
How will you know if your resin is too hot?
*Pot time is shorter than expected.
*The cured resin mixture cracks.
*The resin fills with bubbles (it can look very foamy), smokes and/or melts your mixing cup.
*You notice excessive shrinkage of your resin casting after filling a void or removing from a mold.
How does resin get too hot?
1. You mixed too much resin and hardener at once. Resin kits have a minimum and maximum mixing amount. Too much resin and hardener mixed together produce too much heat too quickly.
2. You added something to the resin and hardener mixture to cause it to heat up too rapidly. While it’s always fun to try different things to color resin, we don’t know every possible outcome. When using paints and other solvent-based colors in resin, these can sometimes speed up the resin curing reaction and cause the mixture to heat up too quickly.
3. Your resin and hardener components were too warm when you started working with them. I am a big fan of warming your resin kit bottles before use as it helps to reduce the bubbles in your resin mix. However, adding this extra warmth to the bottles ‘jumpstarts’ the resin reaction and can make your resin mix get warmer much sooner than expected.
4. You applied too much heat with a heat gun, torch, etc. to remove bubbles. That heat also adds to the heat of the resin reaction.
How can you keep your resin from getting too hot?
Mix no more than the manufacturer’s recommended mixing maximum. This information can sometimes be hard to find. You may need to contact the resin manufacturer directly to get this data. Note: For all the resins sold on Resin Obsession, we have that information for you in the PDF in this article on resin casting.
Mix and pour several batches of resin if necessary. If the amount of resin you need for your project is more than the maximum recommended to mix at once, mix and pour smaller amounts several times. Note: The heat from the mixes is additive. If the layer you just poured is hot, that heat will transfer into the next layer. You may need to wait several minutes to allow the heat to escape from the first layer before pouring the next layer.
Use a slow curing resin. Some resins can take hours to days to cure. They generate heat slower and are less likely to give you the problems listed above.
Maintain a cooler than normal ambient temperature in your work area. While the low 70’s F is the ideal working temperature for casting resin, you may want to work in temperatures in the 60’s F if you are worried your resin mix will get too hot.
Find something that you can use to absorb some of the resin heat. Metal objects can serve as a heat sink which means it will absorb some of the resin reaction heat. This is a great option if you are casting into a vessel. A metal trivet can not only hold the project, but can help to absorb some of the heat.
Have you ever asked yourself ‘Why is my resin hot?’ What was your experience with hot resin?
Unpublished Blog Posts of Resin Obsession, LLC © 2019 Resin Obsession, LLC