Three Ways to Thin Epoxy Resin

Mixing epoxy resin using two metal buckets.
  • 0.5-1
  • Intermediate
  • 25-50
What You'll Need
Hot water
Bucket
Paint thinner or acetone
Measuring cups
Wood stirrer
Denatured alcohol
What You'll Need
Hot water
Bucket
Paint thinner or acetone
Measuring cups
Wood stirrer
Denatured alcohol

Epoxy resin is a very strong material that can be used as a sealant and an adhesive, as well as a myriad of other things. However, one troublesome thing about this substance is that it is very thick and viscous, which means that it can be hard to apply, and sometimes, it will not get into all of the dings and nicks in a surface.

This bad coverage can create pockets of air, causing streaks and making the resin cure improperly. The only way to fix this issue is to thin the epoxy. The following article will show you how to do this correctly so you can get the best, more thorough coverage whenever you use this resin.

Note: Keep in mind that some methods of thinning epoxy resin will lower its viscosity for better coverage but will also weaken its protective properties.

1. The Heating Method

Heating is, by far, the best method for thinning epoxy resin as it doesn't actually weaken the substance in the slightest. Think of it as heating canned cake frosting. In its natural and cool state is very thick, but once you heat it in the microwave for a few seconds it becomes very thin and pourable. The same idea applies to epoxy resin.

Fill a bathtub or bucket with very hot water; use boiling water if possible for best results. Then, take the can of epoxy resin and place it inside. Allow it to sit for several minutes. The heat of the water combined with the conductivity of the metal can will allow the epoxy resin to become much thinner. However, you will have to work quickly when applying the resin after it's heated since the viscosity will return to normal as it cools again.

2. Paint Thinner or Acetone

Paint thinner and acetone are relatively the same with very minute differences between them. It is for this reason that they are interchangeable for the purpose of thinning out epoxy resin.

Be very careful; using either of these products will weaken the finished product, but it can be completely ruined it if you mix them incorrectly. The general rule of thumb is to mix in thinner at a ratio of 10 to one. So, if you have 10 gallons of epoxy resin, then thin it using one gallon of paint thinner or acetone.

3. Denatured Alcohol

Denatured alcohol is ethanol that has been made poisonous, but it's a solvent that is safer to use as resin thinner than paint thinner or acetone. It's properties also allow you to thin the epoxy more without as much detriment to its protective nature. Mix this in the same way as paint thinner or acetone, but at a ratio of about 15 to 20 percent instead.