Al, using two cups arent you still off by the amount of hardner that remains in one cup, assuming you dump the hardner cup into the resin? You'd have to scrape it totally clean for that kind of accuracy.

FWIW, Ive always used the marked cups, and simply poured to the marks carefully. Ive never had a bad mix.

: Not true! A calculator might come in handy for setting up the distances
: between the pivot point and the two pins, but once that's done, no other
: calculations are needed. I've mixed hundreds of batches on my two cup
: balance, and it's very precise, to the accuracy of a single drop of resin.
: With the single cup balance, a weight is needed, but it's actual weight
: need never be known. It's the ratio between the pin lever arms that
: insures tha ratio of the epoxy batch.

: Al in Kingston