Vacuum Pump for Veneering

[Mike Henderson]

I teach veneering at Woodcraft and wanted a pump I could transport easily, so what I did was buy a cheap "dolly" at the borg and build the pump system on the dolly. This will allow me to roll the pump into the classroom instead of carrying it. I have another vacuum pump but I've built it into my shop and it's not portable any more.

I bought the pump on eBay (there's a bunch of Thomas pumps being offered right now) and the brass parts from Joe Woodworker. The advantage of this design is that the pump doesn't run all the time - it only runs when the vacuum falls - so it's quieter in the classroom (only occasional noise).

I do have it wired so I can run it continuously - see pix 3. But that's for "just in case" I ever want to run it continuously. It was easy to wire it with the option so I did it while wiring everything else. Don't know if I'll ever use it.

Mike

[Jim Becker]

That's a really nice portable setup!

[Chris Padilla]

My venturi vacuum is also on a dolly...pretty much looks exactly like the same dolly you have there, Mike!

[Carroll Courtney]

I pick up my pump from the local pawn shop yrs ago when pawn shop were cheap.Now days their prices are close to new.I like the tanks you have on yours-----Carroll

[Terry Hosford]

Mike what is the model # of your Pump?
There are a lot of them on E Bay

[Mike Henderson]

Mine is not on eBay right now, but the 2660 units are good - the last two digits indicate the CFM. So a 2660XXX44 is 4.4CFM. Many of Thomas units on eBay are too small for vacuum veneering. I think you need at least 3CFM and more is better.

Some of the units may be 220V so check the model number (Google it) and make sure it's 115V (especially if the seller doesn't specify the voltage).

Mike

[The one I have is about 4CFM.]

[phil harold]

I like the idea of the cart and the option for continous and intermitent
but
being a portable unit getting moved around should there be some protection around the hoses, gauges, and fittings?
Maybe turn the pvc pipes 90 degrees?
I think I have most of my parts and fittings to build mine now
just need to figure a design that will work for me

[Mike Henderson]

I like the idea of the cart and the option for continous and intermitent
but
being a portable unit getting moved around should there be some protection around the hoses, gauges, and fittings?
Maybe turn the pvc pipes 90 degrees?
I think I have most of my parts and fittings to build mine now
just need to figure a design that will work for me

Good ideas. If I was to do it over again, I think I would do as you suggest and put the fittings at the top - run the "tanks" up and down, maybe one on each side of the pump. Maybe even turn the pump 90*.

They say the best project is always your next one.

Mike

[phil harold]

Good ideas. If I was to do it over again, I think I would do as you suggest and put the fittings at the top - run the "tanks" up and down, maybe one on each side of the pump. Maybe even turn the pump 90*.

They say the best project is always your next one.

Mike

getting it right the third time around
works for me more often that I want to admit

[Mark Koury]

Mike,

What is the small pipe at the top about?

Nice set-up!

[Mike Henderson]

Mike,

What is the small pipe at the top about?

Nice set-up!

Most vacuum pumps will not start up under vacuum (they will stall at startup). So you have a "one way" valve in the line. As soon as the vacuum pump stops running, the one way valve shuts. Then there's a MAC* valve which is electrically controlled which opens when the power is removed to the pump and allows air to flow into the part of the system past the one way valve (removing the vacuum from that part of the system). That small pipe you mentioned is in that part of the system. It just needs to be big enough so the pump does not pull "full" vacuum before it gets up to speed. So it's a buffer that allows the pump to get up to speed before experiencing full vacuum. This only occurs when the pump is restarting after pulling full vacuum on the bag.

The one I have is bigger than it needs to be. About 6" is more than enough. For some pumps you might not need any at all - the pipe in the unloaded part of the system might be enough to allow the pump to get up to speed.

If space was at at a premium, you could use a delay relay to keep the MAC valve open for a couple of seconds while the pump got up to speed. I guess there's a bunch of ways of solving the problem.

Mike

*Anybody know what MAC stands for? Mechanical Air Control???

[Many large air compressors have a similar problem. The compressor has a one way valve and some release mechanism to remove pressure from the pump when it turns off. You almost always hear some air exhaust from a large air compressor when it turns off. That's pressure being released from the pump.]