Vacuum Veneering

Paul Douglass

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S E Washington State
In the future, I would like to try some veneering and use a vacuum veneering process. I wondering if this pump would be good for that?

http://www.harborfreight.com/3-cfm-two-stage-vacuum-pump-60805.html

I know, Harbor Freight, but on sale and I have a 25% off coupon that may be use with it also. These pumps also have pretty good reviews.

And another question, I know nothing about vacuum pumps, this maybe a very stupid question, but can you somehow connect to a vacuum pump so it will blow like a small compressor? Just curious.
 
Paul,

The HF pump sounds like it will do a fine job for vacuum veneering or any kind of vacuum pressing. The 3cfm spec is more than enough to make quick work of pulling down a vacuum bag.

One thing you should consider is setting it up with a vacuum switch so it doesn't run all the time. Most of this type of pump is rated for continuous duty, but it will last longer if you set it up so it can cycle. If you haven't already checked it out, Joe Woodworker has a lot of information on vacuum pressing, etc.

As to using this pump as a compressor, as in operating an air brush, I'd say no. I use a refrigeration pump on my system and it emits a very fine oil spray from its exhaust.
 
You would be better off (my opinion) with this pump from Joe Woodworker and save some money at the same time. Besides, he has all the info to build your press using this, along with all the parts, including the pressure switch to cycle the pump. That's what I built, with the pump I linked, about 7-8 years ago and everything is still working great. They can also be set up to blow, I use a vacuum pump on my pond aerator. That one is a Gast, and it runs 24 hours/day, 7 months a year.
 
Thanks for the inputs. Joe's pump does look like a better deal and with his kit would be a nice setup. I got it bookmarked.

One more question and then I will leave ya'll alone. Could this setup (Joe's) also be used to run a vacuum chuck on a wood lathe? If so I could really justify it in my mind. Never mind I see he has instructions for that.
 
Two types of vacuum pumps for veneering... continuous duty with no tank or cycling system, or the more sophisticated (complex) systems that pull a vacuum in a tank and then cycle as required to keep the vacuum.

I use a continuous duty pump. Turn it on when I glue up, turn it off 10 hours later. Not the quietest thing, but it works great.

If I were doing it again, I would build a Joe Woodworker tank system that is run off a compressed air venturi - one that cycles the air as required to keep a vacuum in the tank. I was amazed at the relatively low volume of air required to maintain a vacuum, once it is established, if it has a tank to provide the continuity of vacuum.

If you have a big bag and a low volume pump, plumb in a connection to a shop vac to take the volume air out of the bag, then use a ball valve to shut off the shop vac port, and start the usual vacuum system.

I am surprised how little vacuum is required for a vacuum chuck. I used my veneering compressor, which pulled a high vacuum. It never seemed to be enough for a very small bowl (2 inch diameter or less) but was more than ample for a larger bowl (where there is more area for the air to push on the vacuum faceplate). Therefore I tried a shop vac to provide the suction on the larger bowls, and it worked fine for moderate cuts, sanding, etc. You have to be really gentle with a 3 inch bowl, but by the time you get to 4 or 5 inch, almost any system is adequate.

I have never used my vacuum pump as an air compressor, in part because there is a sound muffler on the output.

I have never seen a vacuum pump rated in microns. I try to get my veneer vacuum down to about 27 mm of mercury ( where atmospheric pressure is about 30 mm) . That will give about 1700 pounds of pressure per square foot.
 
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