I made my own vac table from a double thick glass fume hood door with sandwiched wire mesh. Then I pulled carbon and foam down into my new tool (rudder half)- and broke the new table. I was using a home built pump- a free, discarded automotive AC compressor driven by an old electric 1/4 hp motor via a belt. CRAK- it said! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />
Turns out my tool wasn't flat enough, and had a 2 inch wide 1/2 inch deep groove down the middle of the underside. Stupid man! Pump plenty strong enough.

I had already pulled too much vacuum on my foam core rudder being used as a plug and swelled it. DOH!