This is especially true of pump that "burp". When in doubt, use graduated mixing cups, and here's a cheap way to make them. This is not my idea (I'm thinking Shawn Baker. Whoever it was, speak up and take credit).

Buy some bulk paper cups at your local Sam's Club or equivalent. Make sure they're the wax-free. For $6 you can get enough cups for many boats. Take one cup and cut a vertical window in it starting close to the bottom of the cup up to an inch or so of the top and about 1/2" wide. Put a 2nd cup inside the cup with the window, and using a graduated syringe or cup, start adding increments of water to the interior cup and marking the levels on the outer cup next to the window. I had to use a flashlight shining into the cup to be able to see the level, but it depends on how thick your cups are. For the initial marks, I filled in 1/2 ounce increments until the marks got too close together (because of the tapered cup) and then I switched to 1 ounce increments. Now you've got the one cup with the window marked, and when you're ready to mix epoxy, just pop in a fresh cup, dispense the resin, check the level, dispense the hardener, and check its level. If they're not right-on, it's easy to adjust the levels to get the proper amount.

Ross

> While pumping a lot of epoxy this past weekend I made a very interesting
> and somewhat disturbing discovery. My pump was not pumping out consistant
> amounts of epoxy!

> I was wetting out my hull and when coming to the more finiky areas I was
> pumping into a syringe to measure out half batches. That is when I
> discovered my pump would sometimes give me 27,25 and 23 ml's!!! The epoxy
> is a 2:1 ratio mixture and I have never had problems with the epoxy fully
> curing. I therefore suspect that I'm within the tolerance of the epoxy
> even though I'm getting these wildly varying amounts. I was very suprised
> because I had understood that these pumps were supposed to be very
> accurate.

> Has anyone else encountered this phenomenon?