West Systems Pumps

I’m approaching the bottom of my first cans of West epoxy. I don’t want to get an ugly surprize when one pump sucks air and ruins my batch of epoxy. I’m kind of afraid to pull the pump and look at the level in case the pump sucks a bubble of air in the bottom and ruins a batch. Any suggestions or facts that may help?

Don - go ahead and unscrew and pull pump to look. As long as you don’t leave if out for a long period of time (hours - not minutes), you should be OK to open and peek.

The pumps have a one way valve built in (big ball bearing and spring as I recall) that shuts off and prevents epoxy from flowing out of the tube when you press pump spout to meter some. Usually, the amount inside the tube is the correct ratio needed - so any drips as you look should not affect your ratio mix. It’s probably resin/hardener that is in pickup tube below the metering ball.

When time for new cans, I usually will pull pumps and pour remaining resin/hardener into the new can so it isn’t wasted. For the slight difference in ratio mixing by pulling pump - it won’t hurt when mixing a single stroke batch. Even if you happen to get one little “burble” of air in a pump stroke, it usually results in a little slower cure time - Unless of course all that comes out is air. Also it will help if you use slow strokes as you get close to the end of a can - it seems a slow stroke will dispense the material. When you push hard and fast is when air is sometimes expelled.


Thanks Dick

I’ve used the pumps when I was vacuum bagging sailplane wings; never had any issues with the pumps delivering a faulty ratio. I did always waste one pump stroke before starting my measures, though, because it was usually a month or better in between building sessions. I can’t say that I missed the wasted epoxy & I always had the peace of mind that the mixture was correct. :cool: