Dave/Steve,
back in the late 80s when I was engeering a electronics printed circuit board process , we use large "turkey" bag that we would put a heavy steel lamination fixture inside of it and seal the end except for the vacuum port, we load them in a cool lamination press and pull vacuum for about 15-20 minutes then close and heat up the press and laminate the B stage pre-preg to the C stage core material. the steel fixture kept everything in alined as when we were done we have to drill thru all these C stage core layers.
we used E glass pre pregs.
it is much more difficult then how i stated as we laminated up to 15 to 20 of these C stage cores together
we use heat and pressure to laminate them all togther
at some point later on ,, we even tried a auto clave to do this process.

thank you
Jim

we pull vacuum for about 15-20 minutes and then la

This was in Kuwait after the first Gulf War there was nothing without tank tracks on it left to work with,
I made the Vacuum pump out of a blasted Air raid warning siren and a 10 HP electric motor, the laminate we were doing would get spotty after 4 HG so the pressure levels were critical,
That was the madness behind the regulator controlled system and that body shop film allowed masking tape to stick and seal close to a tacky tape. the time constraints forced the Co-Bag operation where the laminate and core were done One shot.
I needed a pilothouse a day.

and I was training my crew as we went along.

8000 miles from home and having to make do with whatever we could find.
I hate hand contact open faced molding and will always try to find the material to do a even rudimentary closed mold system, My Dad taught me not to cry about what is not working or missing But find one thing positive and start up from there.

There were a lot of junk yards there filled with war damaged material of all kinds. That was a source for my vacuum pump, the pressure fed roller made from a busted road stripe machine that the pump survived,The gelcoater the same way, this was the way I worked until the Venus machines were shipped in.

Steve

Thank you,,
Jim

Sir you are welcome.

Musta been awfully noisy in the shop when you had to bag something

LOL I had to have a muffler made and a 12 meter stack even though I was using the intake side it was still very noisy and had people running out, But it worked very well,I did the barrel crush test for the Kuwaiti's they were shocked how fast it destroyed the steel drum.

probably tough to get anything done when ya fire up the pump and your work crew dives under a desk (I'm just full of 'em today )


so . . . . I'm think'in i should try this barrel crush test with my new pump. Whats involved, just seal up a drum and hook up the pump? I do have a couple of 55'ers i need to get rid of. How small they get?

How much lbs/sq inch does 29 HG convert to?

oh wait thats a perfect vacuum and about 14 psi or something like that.

Dave
If i remember correctly
at sea level perfect vacuum would be 29.92 inches of mercury or 14.70 PSI or 1 bar
been a long time since i worked with vacuum pumps and systems

Thank you
Jim