Veneering, how much vacuum do you use?

[Jeff Nolan]

How much vacuum do you use for flat veneered panels?

[Jim McFarland]

I use one of Joe Woodworker's systems and gauge reads -25"Hg when the pump shuts off and cycles back on at ~-20"Hg. No problems with bubbled veneer to date so this range works for me.

Edit to add: Gauge reads 0 @ atmospheric pressure so to be accurate I need to add ~30 to above #s.

[Mike Henderson]

I use one of Joe Woodworker's gauges and I set it to cycle off at -22 inches of Hg. It comes back on about -18. Also no problems.

Mike

[Paul Atkins]

As much as I can get - or as much as needed. I've crushed hollow structures because I used too much, but never had too much for flat stuff. I didn't but a gauge on my new setup, but will for my vacuum faceplate. We are only talking 14 lbs/in here. Yeah, I know 2000 lbs/sq.ft., but a leak can reduce that quite a bit.

[Jeff Nolan]

Thanks, I currently run about -20 Hg but wanted to ask in the event there is a rule of thumb. I have run it down to about -25 and as little as -15 without any change in finish result.

As Paul indicated, leaks magnify with more negative Hg.

[Frank Drew]

My vacuum pump was a used lab grade model and would pull close to the theoretical maximum vacuum, which is where I ran it.

[Steve Rozmiarek]

I run mine similar to Mikes. Pressure on the veneer will vary with elevation changes though.

[Jim Tobias]

Vacupress set up here. Turns off at 23hg and comes back on around 20hg.

Jim

[lou sansone]

as much as I can get with my system - 22 inches or more