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Mixing Small Amounts of Epoxy

The System Three epoxy that comes with the Pygmy kayak kits is great stuff. They include a set of measuring pumps that dole out the appropriate amount of resin and hardener in the required 2:1 ratio.

The only problem though is that many times you don't need the large amount of epoxy that the pumps put out. The pumps are great for medium and large applications. You'll want that much when you go to wet-out some fiberglass cloth for instance. However, if you're just gluing a couple of seams or doing a number of other jobs that require small amounts, you'll end up wasting a terrific amount of epoxy before you're through.

I get around that using a trick that I gained from making RC sailboats. You can easily adapt this trick for kayaks too.

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First, get yourself two plastic syringes that are commonly used in epoxy work. You can find them at West Marine, Fisheries Supply, and other places. Look online too. Cut the tips off of them so that the holes are large enough for the thick resin and hardener.

Slightly sand one side of each syringe so that a Sharpie will leave a fine line. Then using a ruler, carefully measure out a few marks on the side of the syringe intended for the hardener. I used 10mm marks but you can do whatever you feel would be reasonable. Then slightly sand the other syringe and make the same number of marks but make them TWICE as far apart as the hardener syringe. This will give you the appropriate 2:1 ratio. As long as your marks are consistent then you're in good shape. Mine are 10mm apart on the hardener and 20mm apart on the resin.  

NOTE: You can do the same idea for other brands of epoxy that use different ratios, just be sure to make the resin syringe marks the appropriate multiple. For example: WEST System 105/205 epoxy uses a 5:1 ratio. In that case, you would make your hardener marks much closer together, perhaps 1/8" or so, and you'd make your resin marks 5-times that amount.


Then find yourself two glass or plastic jars with lids. Preferably they will be fairly wide relative to the depth. You can't get your syringe too deep into a deep jar. I used 4 oz. canning jars I found at my local grocery store.

Now use your epoxy pumps that you've set up and fill one of the jars with hardener and the other jar with resin. I found 4 oz. canning jars with lids. The hardener jar took six pumps of hardener and the resin one took three.



To make it easier to move these around, I jimmied up a cardboard box that keeps the jars separated and also stores stir sticks, mixing cups, and small acid brushes that I use on small jobs.



To mix small amounts, simply stick the tip of the RESIN syringe into the resin jar, draw out one "mark" of resin, and squirt it into a mixing cup. If you get air bubbles then just gently push the resin back into the jar, and draw deeper and slower from another part of the jar. Then suck up one "mark" of hardener with the HARDENER syringe and add it to the mixing cup. Stir up with a craft stick and use as needed.

If you need twice the amount then just draw two "marks" with each syringe. Easy.

Below is an image I used from my RC Sailboat blog. The marks are much closer on that syringe because it is gauged for WEST System epoxy, but the theory is the same. You start with the plunger all the way in at the shoulders of the syringe and pull the plunger back as many marks as is needed to suck up the epoxy. Use the closest rubber ring as your gauge. The plunger forms a perfect seal into the thin part so that using the first ring gives a very accurate amount. 



MAKE SURE THAT YOU NEVER MIX UP WHICH JAR TO DIP WHICH SYRINGE INTO!

Keep the syringes SEPARATED in empty mixing cups so they never touch, and so they can drain into something. These syringes should last for years. I use this system a lot in RC sailboats and a pair of syringes can last a year or more.




Cheers!




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