Building vacuum press for veneering

[dale martin]

I've been looking around the archives here and have found some information and a couple of great websites about building a vacuum press for veneering. What I plan on doing is mostly smaller sized panels, maybe 10" X 14" or so. I know I could go old school and use cauls, etc., but I'm interested in piecing together some kind of vacuum system, on the cheap if possible. My questions are as follows. Harbor Freight sells vacuum pumps, not the venturi type, but actually vacuum pumps for use in refrigeration and a/c systems. What I'm looking at is the 2.5 CFM model (98076-4VGA ) that sells for about $75. If I use this with a purchased vacuum bag, what more is there to it than to hook up the appropriately sized hoses and switch it on? Do I need an extra reservoir or additional electric parts? Will this sized pump have enough power to adequately pull the veneer to the substrate? Will the pump be running constantly or once it reaches maximum pressure shut off and only cycle on when vacuum is lost due to leakage? Any insight as to if this is a viable plan would be appreciated. TIA.

[Morris Dovey]

I use an old (~25 years) refrigerator compressor with vacuum pucks to hold boards and plywood to the table while they're being machined on a CNC router. Not what you're doing, but I think you can save the $75 if you're willing to recycle.

my 7500 cents worth :)

[name]

dale martin skreiv:

If you haven't already, have a look here:

'll find all the info you will need.

[Art Greenberg]

I think the HF pump will work, but you'll probably need more than just some tubing to hook it up.

No matter how hard you try, the bag won't hold a vacuum forever. During the time you're waiting for the glue to set, you'll probably need to start the pump a couple of times to maintain the vacuum (and the amount of clamping pressure). With a partial vacuum already present, that pump might not start. I bought a kit of parts from JoeWoodworker.com that included a "MAC" valve - which is nothing more than a switch with a time delay that lets the pump pull from ambient for a few seconds when it starts, then switches over to the vacuum line.

Also, its a bit more convenient to use a vaccum switch to control the pump. The one that came with the kit is adjustable, and it works very well.

If you look at the plans on the Joe Woodworker.com site, you'll see that a vacuum reservoir is also used. This is to reduce the number of pump startup cycles. Doing so extends the life of the pump.

I think you'd do well to look at a few different designs and some of the free plans available before building your system.

[Nova]

Bill Nobel, who frequents the wood turner's news group "rec crafts.woodturning", often has rebuilt Gast vacuum pumps that he sells at very reasonable prices. You might want to check his site to see what's currently available or put you name on his waiting list and he'll notify you when something becomes available. The site is:

[EXT]

Also if you can find a repair shop that specializes in fixing small duplicator printing presses, they use vacuum pumps to move the paper, Gast is a common brand. They seem to last forever so a used one may be reasonable in price. I have one that I haven't used yet to make a vacuum clamp. The vane type pumps are particularly good because small bits of dust, lint and sanding dust that gets sucked into them does not harm them at all. They are built to take it.