Epoxy resin is a strong material that is used for a number of applications, including as a sealant, an adhesive, and in a variety of creative projects.
Unfortunately, because the epoxy resin has a high viscosity, it can be difficult to work with.
To elaborate, it can be hard to apply, and it doesn’t easily move into those corners and hard-to-reach places.
This could mean that air pockets may form and make the epoxy resin not cure correctly.
To avoid this, one thing you can do is thin out the resin a bit with solvents like xylene.
I have thinned out the epoxy paints using Xylene many times and it worked great for me.
For beginners, however, it can be a little hard to mix as it doesn’t dissolve too easily with epoxy resin.
And that’s the reason xylene is not among the most common solvents to use for thinning epoxy.
Thinning Epoxy Resin
When you thin epoxy resin, you are lowering its viscosity.
This will permit the resin to more easily flow, which is especially important on porous surfaces like rotten wood.
Thinning epoxy will also allow it to brush onto the surface more easily and saturate fiberglass more efficiently.
In order to thin epoxy resin, there are two different methods:
- Heating the resin
- Adding solvent to the resin
Both of these methods bring the same result of thinning the epoxy and reducing the viscosity.
Below, we will show you how to thin epoxy resin as well as what you should look out for and expect during the process.
Keep in mind that there are some methods you can use to thin the resin that might lower its viscosity, but it might weaken the protective qualities of the epoxy.
Method 1: Heating Epoxy
Heating epoxy to thin is thought to be the best option for the job since it won’t weaken the resin at all.
Compare this method with what happens when you heat canned frosting, which is also very thick.
If you put it in the microwave for a few seconds, the viscosity is low enough that you can pour it. This is the same idea for epoxy resin.
Fill a bucket with very hot water, boiling water, if possible, for the best results.
Place the closed container of epoxy into the hot water in the bucket.
Allow it to sit for several minutes. The heat of the water combined with the conductivity of the metal can allow the epoxy resin to become much thinner.
The epoxy resin and the bucket both need to be handled safely so that you don’t burn yourself.
Be careful not to overheat the resin. If you see smoke coming from the epoxy, it is overheated and will need to be replaced.
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.
That said, if you’re working with wood and need to thin the epoxy, it is best to heat up the wood and let the epoxy resin remain at room temperature.
Then you can mix the hardener and the resin and put it on the warm wood.
As soon as it touches the wood, it will start to thin. As the wood starts cooling, the epoxy will be pulled into the wood and it will grow thicker.
Method 2: Using Solvents for Thinning Epoxy
Using a solvent to thin out the resin is a swift and quick method, but it can negatively affect the compressive strength of the epoxy.
We don’t recommend this method for that reason. Even so, if you proceed with it, there are some recommended solvents.
This includes xylene, lacquer thinners, denatured alcohol, and acetone.
Xylene solvent is often used in the production of adhesives and sealants, paints, lacquers, varnishes, and other industrial and manufacturing products.
The solvent can also be combined with other solvents, such as toluene or mineral spirits, to form a more versatile cleaning solution that can dissolve a variety of organic compounds including oils, greases, and waxes.
While it can also be used for thinning epoxy to achieve the right consistency, its highly flammable properties make it less common among DIYers and woodworkers.
b) Denatured Alcohol
Denatured alcohol is ethanol that is considered poisonous but is also widely regarded as safer to use than other thinner solvents.
This solvent will let you thin the epoxy with less danger of damaging the strength properties of the resin.
You should use a mixing ratio of 15 or 20 percent of the volume, which will mean taking 30 fluid ounces from the resin and mixing it in with two fluid ounces of the alcohol.
c) Lacquer Thinners or Acetone
These two solvents are very similar and are therefore commonly used as epoxy resin thinner.
Be careful when you’re using these solvents since they can weaken the strength of the resin and can also ruin the resin if you mix it improperly.
The best mix ratio is 10:1. So, if you use 10 gallons of epoxy, you will need to mix it up with one gallon of acetone or lacquer thinners.
These solvents are easy to find while also being exceptionally good for thinning the material.
Furthermore, these solvents will quickly evaporate and aren’t likely to get trapped in the cured resin.
Below are a few consequences that could come with using epoxy thinners:
- The solvents may pose a fire risk
- Solvents can reduce the compressive strength of the epoxy
- Acetone may cause the color of the cured epoxy resin to change
- Using a solvent to thin epoxy resin will prolong the time needed to thin it
- Thinning the epoxy resin with a solvent may make it shrink or crack over a long period of time
The Bottom Line
In some cases, you may need to thin the epoxy resin before you can work with it. In other cases, it might not be necessary.
Examine the materials you are working with and think about the project you are making and decide from there.
Be sure that it doesn’t overheat, so all of the properties of the resin stay intact–you will be good to go on your next epoxy resin project.
Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for more than a decade to serve the customers in areas such as Charleston, Mount Pleasant, Beaufort, Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques that are being implemented in his profession. You may read more about him here or get in touch with him here.
Just in case you want to hire pro painters in your local area, you can click here. We can instantly send you free quotes from trusted painters based on your specific requirement.