I have mixed both epoxy and polyester for 35 years and have never had a
batch go bad. It ain't brain surgery. All you have to do is follow
exactly the manufactures directions. I have to agree with Meindert, if
you can't do that, you might want to think about whether you need to be
building a boat with two part resins! Only an amateur would
extrapolate to broad use the brushing on of catalyst over polyester
resin already applied to glass as described by Johns for one boat.
There is not a poly resin supplier in the word that would suggest such a
thing because there is no way to predict what the final properties would
be.

As to epoxy, I have mixed batches from 1 gal. down to 6 drops. Yes 6
drops (5:1 West) off of popsicle sticks for RC model aircraft building.
For larger batches I use any container of suitable size thats at hand
and mark off the ratio with a rule. Gee I'm glad I passed 7th grade
math.

Allan, the bottom line is that it is historically well established thru
industry testing, both lab and field, that epoxy is superior to
polyester in most ways except price. No amount of anecdotal evidence or
backyard observations as put forth by the polyester crowd will change
that.

Regards, Ron

PS. Meindert, I learned to measure epoxy in the lab at GE a long time
ago and was doing it on a balance scale until a couple of years ago I
was corrected by Kern of System Three and several other chemist here.
They all said that now the published ratios for the formulated resins
are for volume only as the weight ratio can be different. I never had
any trouble that I could detect but I do by volume ever since to assure
max mech properties.

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.