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Q-talk 103 - Simple Balance Scale

I've notice the recent discussion about converting epoxy pumps to the correct ratio. There's actually a very simple method to mix any epoxy brand, regardless of the ratio, exact every time in one cup. You may recall the original plans called out for 43:100 by WEIGHT. The error came from filling two cups and transferring to one cup for the mix. This is wasteful. An easier method is to construct a very simple balance beam, which can even be a board balanced on a pencil, or hanging, whichever you choose. Place your empty cup on one side and a couple coins on the other, the balance at zero net. Add squirts of resin to the cup and place 100 grams of coins (example 20 - nickels) on the other side. Move them in/out until you get it balanced. Place 43 grams of coins (example - 7 quarters) on the first stack and add hardener to the cup until it's balanced again. You may tape the coins together with scotch tape, if you wish. That's all there is to it! You can choose the amount of resin each time (instead of 2 or 3 exact squirts) or change ratios if you choose to use different epoxies. The average weight of US coins are:

6.20 g per Quarter5.00 g per Nickel
2.36 g per Dime2.60 g per Penny

(FYI - All weights have been verified with multiple coins on a digital lab scale).

I have used this method for years and it's very quick and accurate. I don't have to worry about clogged pumps or air bubbles. I have found 200g/86g seems to work well for 2 or 3 squirts and a shorter balance.

You can order a printed copy of Q-talk #103 by using the Q-talk Back Issue Order Page.