: Gizmologists? Hmm. Well, we're both zymologists Does that description fit
: you as well?

I don't know what is it? I have been called many things but never a zymolgist?

: A few of these? I knew it! After the first one, well, I just want to improve
: the efficiency!

That is what got me tinkering also. A Grand Canyon guide showed me a pump that was better than everyone elses, so I took it apart to see what made it tick. What I found was discs that were full of holes like a sink drain and the nylon neoprene plunger flap material that was precision cut, friction free.

I ended up making one for a guide friend and one for myself. Then I could not resist making a stubby one out of 4" pipe. It is too heavy to be practical but if there is ever a contest, I am ready.

: Ooh... Interesting... I might be persuaded to try something like that - when
: I find some lighter pipe! (Right now my main pipe is schedule 40 - way
: overkill for the job!)

I am not tinkering with pumps now but if I get back to it I will try putting one wrap of Carbon fiber around a plastic mailing tube to cut some ounces.

I'll get some photos to Shawn in about a week.

The flap material is nylon neoprene from a military surplus dry bag vintage 1964. If you would like a piece of the material send me an address.

Good luck.
Reg

: I switched to using some sturdy vinyl fabric for the same reason.

: It started getting fun about the time that it started working! Now, I've just
: got to make it fantastic...

: cheers!