: I ran into the burping pump problem in the middle of laying up a carbon fibre
: rudder. You can bet I said a few choice words. I muddled through and the
: rudder came out fine.

: Afterwards I disassembled the pumps and found the problem. The epoxy had
: gotten quite gummy around the steel balls that create check-valves at the
: bottom and in the head of the pump. Consequently they were not functioning
: properly and caused the burp.

: One hour and 1/2 a gallon of lacquer thinner later they're shiny clean and
: pumping normally again. From now on I'll make it a point to clean the
: pumps before any major epoxy work.

Pumps are $3.

Lacquer thinner is $7-10/gallon.

Stress saved is priceless!!! If you have time, it's probably a better idea to buy new ones!!

I stick to measuring cups, and ignore the burps...I used to count pumps, and had a few batches not cure.

Shawn