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Simple way to measure epoxy

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This thread might be better placed somewhere else. Go ahead and move it if needed.

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. Another method is using a graduated measuring cup.

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 just want to use a more visual method, here's an easy way that doesn't require using pumps (or purchasing graduated measuring cups).

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

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There's another way too. Shown to me by Meade Gougeon at an Experimental Yacht Soc meeting LONG ago.

first- you need a straight sided container- flared ccontainers give incorrect results.

Take a straight stir stick with a square end. Measure up the resin amount, such as 1/2 inch ( 0r 1/4, or 1/8, whatever) for 2 to one mixes, or 5/16ths, etc, for 5 to 1. Draw a line across the stick.

Then measure up one more increment and draw another line.

put the stick into the container and add resin to the first line. Then add hardener to the second.

I often use the inner section of a spray paint cap and mix maybe a tablespoon full for small job.

Also- when you are doing a large job, such as glassing a hull, you can pre pour several containers of just resin and set then on your work table. Then when you need another batch, just add hardener and stir. Makes getting another batch a snap.

When I was buiklding the trimaran I saved empty tin cans from the kitchen to mix epoxy in. After several uses I pitched 'em

Yours is a quite good idea also by the way.

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Guest Sam A

Another way is to go to WalMart and get their 8 and 16 ounce clear plastic glasses with the ribbed sides.

If you pour resin in to the bottom of the first ring, hardener to the top of the second ring, you have perfect 2 to 1 ratio.

Test with pumps first, but for me either 75 ml (3 oz) or 150 ml (6 oz) of epoxy depending on which cup I select.

They have smaller cups, but I have not measured them yet.


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I have found the best way to mix epoxy is to use 1 to 1 ratio type. I get mine at Clark Craft. I use different size of paper cups (non wax type). If I need 6 oz, I use two 3 oz cups and just throw them away after use. (they burn well in the burn barrel) I found a large box of assorted paper cups at a garage sale a few years ago. Got enough to last many more years. You could use other ratios by using some sort of standard, but paper cups are cheap and available most anywhere.

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