: Hello All,

: Has anyone else had trouble with their plunger-type epoxy pumps? I just had
: another one go bad. During the downward pump stroke, it spits a slug of
: air. There must be a bad seal or check valve that lets air in during the
: up stroke even though the pump is almost new. Is there a fix for this? For
: some reason, it is only the resin pump that I have had trouble with. I
: tried heating the resin and pump thinking that there might be some
: crystalized resin gumming things up, but it didn't help.

: Thanks,

: Jon

There is a ball bearing that works as a check valve on these pumps. I've found the resin drains down past the ball
bearing but the hardeners don't. Obviously it has to do with a viscosity difference between the two.

I always assume the pump column on the resin will have drained a bit after standing when not used that day and do a few
short strokes to fill the pump column up until I get a drip of resin out of the spout. Then I pump a full stroke with
out air problems. If I get a burp of air I'll add a burp of resin after the stroke.

Good luck!

Rob