Frugal Person's Vacuum Press Question......

[Mike Langford]

As some of you might know, I'm cheap ......err.....A FRUGAL PERSON

Because I'm thrifty my redneck brain is constantly tryin' to come up with inexpensive ways to do certain tasks in the shop.....So, I was wonderin' if anyone has tried to use any of the space saving vacuum storage bags (The kind you fill with clothes,blankets,etc. and use your home vacuum to suck out the air...) as a Veneer Vacuum Press???

They're sold in different sizes under names like - The(original)SpaceBag, Suck & Store, StoreMore, etc.

I've never done any veneering but would like to try it (on small pieces) and before I plop down $8 buck or more (remember I'm frugal) I'd like to know if anybody else has tried this and how did or didn't it work......Or what your thoughts are on if you think my (hairbrain?) idea would work or not!.........

SpaceBagXlg.jpg................Could It Work?

[Zahid Naqvi]

My understanding is that a vacuum press requires a much higher pressure than what a home vac can produce. I can't quote numbers, but I have a vague memory of a similar question asked by some one else a while back. The general opinion is the home vac can't produce enough vac pressure to create enough force to hold down veneer for glue up.
Perhaps someone with more knowledge can chime in.

[Roger Barga]

Not sure what you mean by small, but clamps and heavy 1" cauls are used to press veneer skins for jewelry boxes and the like (8" x 12"). For even larger projects you will need to use strips that are slightly tapered in the middle to apply pressure to the center of the panel you are pressing. Granted it's more work than a pump press but you may already have everything you need, and that's frugal ;-). Finally, to answer your question directly - woodcraft and rockler both sell veneering kits using the hand pumps and bag and from the reports that i have read, they work...

roger

[Mike Langford]

Thanks for the replies,guys.....anyone else?

As far as projects go I was thinking items like small boxes and maybe electric guitar bodies.....The jumbo size SpaceBag is roughly 3'x5'

Plenty enough room for a guitar body/flat panel, sandwiched between a upper and lower caul or platen with slots milled in to aid in air removal.

I looked at the large one (a little under 2'x3') at Wally World the other day.
Depending on the size of your work piece,there was enough "area" near the zip-lock type closer to fold and clamp it shut securely......

.....And looking at the "valve" it looked like it was made to seal tightly once the vacuum was removed. (also comes with a cap to cover the valve)

Hope others will chime in.......I'll check back in a minute or two, but right now I gonna slide on over to the WoodCraft and Rockler web sites and check out the veneering kits that Roger mentioned......I'll be baccck....

[Jim Becker]

The seals on the "space bags" are not that terrific in my experience. We used them when we traveled to Russia and also use the larger ones for some storage at home...they "inflate" a lot faster than I would like.

I recently put together my vacuum press from Joe Woodworker. I actually opted for the better bag. Yes, it cost a little more, but I also expect to get many years of use from it...

[Ed Bamba]

If you have an old fridge laying around check out this site: http://www.berkut13.com/sucker.htm ,can't get any cheaper unless you stumble across a free vacuum pump.

Ed

[David DeCristoforo]

That might be just a bit too frugal! To be effective, a vacuum pressing system needs to be able pull as close as possible to one atmosphere of "pressure". A true vacuum would be one atmosphere or 14.7 PSI or the barometric equivalent of 30 in. of mercury. The best I have ever been able to hit is 27 or 13.5 PSI. A household vacuum cleaner will not be able to get close to this. In addition, as Jim B. points out, these bags are not really designed to hold up to this kind of use. Compressing clothing and pillows can be accomplished with much less pressure and even if you could draw enough vacuum, the bags are likely to rupture or tear.

Actually vacuum systems are "low pressure" systems. You can generate much greater pressure than 13.5 PSI with a "C" clamp but not over an entire area and not as evenly as a vacuum press. It is this consistent pressure over every square millimeter of surface area that requires a fairly strong material for the bag and a really good seal to hold the vacuum.

[Nathan Conner]

Let me also chime in on JoeWoodworker. He has some great FAQs on his site about this very thing, along with a few good explanations of why, exactly, this won't work for what you're trying to do.

There was a thread in 2005 here about an even better option - making your own vacuum bag from plastic purchased at Wal*Mart, closure with a pair of PVC pipes, one split in half and slipped over the other with the bag between and a salvaged Gast pump. Might be worth a read.

I also put together a kit from Joe last week, and also opted for the better 4x4 bag. Looks like great quality stuff, and should hold up to years of use. Very nice kit (I think I did the V2 Premium Venturi, or something), and well worth the cost - simple to build, nearly silent to run, and quality parts. I'm also a bit...ummm...frugal, and was really, really impressed. Joe's also a tremendous help.

[Charlie Plesums]

My veneering instructor makes his own bag from WalMart vinyl or roofing material or whatever... for huge bags required for conference tables, for example. But for everyday use, I sprung for the bags from Joe Woodworker.

I second the recommendation of the advice from Joe Woodworker. As you read about vacuum, put things in three categories (the major choices as I see it)

• Continuous duty pump... small, quiet, run continuously as long as you want a vacuum on your bag. Best for smaller bags, but if you use a shop vac to get the bulk of the air out initially, then the small pump can keep the vacuum on even a large bag.
• Pumps with tanks... Larger pumps that run intermittently, as required to keep the vacuum. The larger capacity of the pump and tank is better for working with larger bags,
• Venturi systems driven by air pressure (some with tanks, others without). Uses very large volumes of air... do you have a large shop compressor?

[Frank Hagan]

Roarockit has been selling vacuum presses for building your own skateboard for a while ... and they use a hand vacuum pump. Rockler has an article on them, and if you Google "roarockit vacuum press" you'll get some links to Fine Woodworking and others who have tested it to good effect.

[Matt Meiser]

I used a space bag with a vacuum pump to veneer some panels. On the first panel, I put a hole in the bag which I fixed with duct tape. I was able to complete all of the panels for the project, but made a vacuum bag later with vinyl from Wal-Mart. We've used some in the house and as Jim said they can be leaky (seems some are, some aren't based on the 3-4 we have.) I also don't think you will get the kind of clamping pressue you need with a vacuum cleaner. Also, most shop vacs rely on air flow to cool the motor, so extended vacuuming of the bag could be bad news. Not sure about household vacs.

[Jim Becker]

The one thing that the "made for the job" bags do is easily stretch and conform to the shape of the "victim" and go back to shape afterward...without puncturing. Important in the long term...

[David Epperson]

David DeCristoforo. I think you've hit the right area. 14.7 pounds per sq. inch is max. 13.5 takes a fairly decent pump to achieve and maintain. 10 psi might be doable on the cheap - which is what 1440 lbs per square ft? Do you need more? To do any better for any less would mean increasing the external pressure. You could get by with less vacuum if you had a pressure vessel on the outside. (some way to put the plastic bag inside your air compressor tank, or at the bottom of the pool (8ft of water is only around 3 to 4 psi though). )

[Hal Flynt]

For a cheap pump:

I have a 70's vintage air conditioner compressor from a Ford pickup/van bolted to a length of 2 x 8 (I had a couple of V belts, so that determined the length). I had a washing machine motor with a pulley, wired up a switch and used it to service my Auto AC for years. It will pull over 30" of mercury in a very short period of time.

I think I paid $5 at a flea market for the pump. Took the motor out $0, Used some vinyl sheeting that I had.

I used it for one vacuum veneer project and simply slipped a vacuum line over the suction side and silicone RTV in the bag. Great.

I plan to rig up an automatic switch that would cycle off and on should there be a pinhole leak.

[Bill Arnold]

As some of you might know, I'm cheap ......err.....A FRUGAL PERSON ...

I've never done any veneering but would like to try it (on small pieces) ...

The others have given good advice, but how small are the pieces you want to do and what shape are they? If you're doing small, flat panels to incorporate into projects, you can accomplish that with a clamp system rather than a vacuum system.

I've done quite a bit of vacuum pressing of bentwood laminations and veneered panels. There many different ways to accomplish those processes as has been mentioned. I had the good fortune to obtain a refrigeration pump from a friend to start my system. My first bag was a $5 shower curtain from WalMart!