> The cost of the vacuum pump is a lot, but in the grand scheme of things, I
> don't think it is "prohibitive." (It's cheaper than a decent
> table saw, for instance.) I bought a Gast pump capable of pulling
> >20"Hg last year on Ebay, thinking it would be useful both for FRP
> projects and for veneering. I have yet to set it up with pipe fittings, a
> regulator valve, etc--and I haven't even spent enough time yet to figure
> out how to attach an electric cord to the motor. So I can't offer much
> expertise.

I have done vacuum bagging on a couple of the planes I have built. The first used pre preg glass sheets that were epoxied on to a foam core to make the wing panels. The most recent were done when I was making the cowling for my Zodiac.

In both cases I used the vacuum pump that we all have, or should have in our shops...yes the shop vac. With the 16' X 3' wing panels, the pressure was tremendous. some builders had to put regulators on the reduce the pressure. since my foam cores wer solid, I just went ahead and ran it full bore for 24 hours. The shop vac handled the abuse of doing this 6 times, (wings, stab, ruddervators), with no problems. In fact I threw it out 15 years later 'cause I wanted a bigger one and it was noisy as hell. In any case a shop vac will do the job, but whatever you do do NOT vacuum bag the kayak as a closed structure. I think the pressure would crush it. You could fairly easily bag the hull and deck separately though.