Simple Way to Measure Epoxy


Well-Known Member
This demonstration and others can be found at

Epoxy is made of 2 parts: Resin and Hardener.

Most epoxies call for a 2:1, 3:1, or 5:1 ratio of Resin and Hardener. One way to measure the appropriate amount to use metering dispensing pumps that are offered by many suppliers.

These pumps typically are very reliable but they do break down after a while and let air into the pump. This causes the pump to "burb" and give an inaccurate amount of Resin or Hardener. So if you don't have reliable metering pumps or want to use a more visual method, here's an easy method.

Helping in the demonstration is our 8-year old assitant who happens to be the "E" in JEM (JEM Watercraft). :D

Please note: This method shows how to mix a small amount of epoxy with a 2:1 Resin-to-Hardener ratio. This can be adjusted for more epoxy or different ratios.

You'll need some clear plastic cups and a permanent marker.

Place one cup inside another.

Decide how much total epoxy you want to mix at one time. In this example, we selected about 1/2 of the plastic cup.

With the marker, draw a line on the outer cup. Label it "H" for Hardener.

For a 2:1 ratio, you have 3 total parts: 1 part Hardener and 2 parts Resin. So we marked our line about 1/3 up toward half the cup. If your epoxy is 3:1, then you'll have 4 total parts. Mark about 1/4 the way up.

In this next part, we use water. Much cheaper and easier to clean up if you make a mistake.

With an empty cup still inside the marked cup, fill to the marked line.

Remove the inner cup and set aside. Measure 2 more parts so you have a total of 3 equal parts.

Place a cup back inside the marked cup, and pour the 3 equal parts into the cup.

Mark another line on the cup and label it "R" for Resin.

So when your ready to mix, first fill the inner cup with Hardener up to line H, then fill with Resin to line R. Remove the inner cup and mix. Save the marked cup for the next batch.

Easy! :D