Vaccum press on the cheap?

ed sautter

Member
Messages
238
Location
Cortland NY
I am always looking to do something cheap. I now want to do some veneering on some baltic birch ply to spruce it up. I have looked all over trying to find something to do it and not cost an arm and a leg. I know the vaccum presses with the motor are the way to go if your into doing this all the time. This something I just don't have the bucks for right now. I did a search to find alternitives and I believe I have found a low cost hand operated one I am interested in. I've see Norm Abarms using one in one of his shows but didn't know where to get one. Well here a link to one that looks to be easy to use and just the size I will need to do my project.

Now my question is this do any of you have insite on this vaccum bag kit? Pro's or cons? Any other ideas within the 100 or less price range in a vaccum bag that worksas well as the electrical pump ones? I'm not worried about a little work to get the result I want. Just don't want to waste the money on someting worthless. Any help woulf be great. Thanks all.


http://www.roarockit.com/proddetail.php?prod=01301
 
I've read the stuff that Joes woodworking has to offer and it is a good place to get info on veneering. As to the size I'm not looking for anything larger that 24" sq at this point. I just want a real good veneer to ply bond without having blistering and such. Heavy weights will work on small pieces but when it comes to large areas they just don't work well.

What do you guys think of this vacuum bag kit?
 
I understand that kit will work as intended but I've never used one. You have to check it occasionally to be sure it's holding vacuum. For something the size you're talking about (and would fit in the kit bag), i.e., 2' by 2', I would use cauls and clamps or iron the veneer on.

What type of veneer are you using, paper-backed or solid?
 
Bill, thanks for the input. I find that the iron on venner has not lasted (stayed on) and given me any thing I would call great results. I would better off building it from solid stock rather than hassel with poor results. I just don't want to use highly figured woods in thicknesses because it's wastful I could do so much more with it being it were thiner. I have only to veneer the face as the edges will be covered and most will not be exposed. The veneer that I'm planning to use is like 1/32 and is bare wood back. I do like the idea of a vaccum bag for quality pressures and overall better clamping.
 
Another choice, since you said you're using solid wood veneer, is hide glue.

As to ironing veneer, I learned the technique in a commercial shop that built high-end furniture. I did some iron-on paper-backed veneer on pieces I built years ago and there's been no issue.
 
Two issues with paper back veneer - one, the wood is extremely thin - often as little as 1/100 inch. Second, the paper shows at the edge - you need a molding to cover it.

A few years ago there was a "fad" of a vacuum bag to build a skateboard. The bag isn't hard (I know a pro who makes most of his own bags), the mesh bags used for some fruit will allow the air to exhaust where the bag wants to seal to the wood, and the gimmick for the skateboard folks was a pump used to take the air out of wine bottles. Certainly not the strong vacuum usually used in a vacuum bag.

Creating a "real" vacuum gives a 2x2 matrix of decisions.... pump or air pressure on one axis, and continuous or intermittent operation on the other axis.

A vacuum pump isn't cheap, although occasionally a used one is a good deal (but used ones can also have medical contamination and still operate). I have a continuous duty small pump that pulls about 28 inches of mercury, giving about 1700 pounds clamping per square foot. Since it is small, it takes a long time to evacuate a large bag, but isn't a problem to hold vacuum 10 or more hours.

Some people use a larger pump with a tank (or home-made PVC tank like Joe Woodworker suggests). With the larger pump and tank the bag evacuates faster (good) and the pump only has to run intermittently, but requires controls to start and stop the pump.

I was afraid of the amount of compressed air that would be required to create a vacuum. After I bought my pump, I was surprised at how little air was required to create a vacuum, so I would consider the air driven vacuum system if I were doing it over. This may be the cheapest solution if you have an air compressor.

The compressed air systems can run continuously (hopefully your air compressor would run intermittently, but you will be using a small amount of air continuously). How much air would be required to maintain a vacuum over time ... I don't know, but hopefully only a small amount, depending on the condition and quality of your bag, and the quality of the bag seal.

Then the fourth box of the 2x2 decision matrix is a tank system that draws compressed air intermittently, as needed to maintain vacuum in the tank, and thus in the bag. I believe this is what Joe Woodworker has for his personal use.

I now have three vacuum bags, and my favorite by far is the small poly bag from Joe Woodworker (VeneerSupplies.com). On sale, it is around $100 for just the bag, but worth it!
 
Last edited:
... I now have three vacuum bags, and my favorite by far is the small poly bag from Joe Woodworker (VeneerSupplies.com). On sale, it is around $100 for just the bag, but worth it!
Or, you can be frugal and buy heavy weight clear sheet vinyl at a fabric store and make your own bags of whatever size you need. Cut a piece twice as long as you need, fold it over and apply vinyl cement on two sides. Make a closure clamp with two sections of PVC pipe; 1/2" inside a 3/4" that has been cut open. Works like a charm!

Note: The first vacuum bag I made was with a cheap vinyl shower curtain.
 
I have a couple 'good' vinyl vacuum bags, but I've also used those "Space Bags" they sell on TV - and in many stores as well - quite successfully.

I have a Gast vacuum pump, and the good (Joe Woodworker) vinyl bags use a Schrader (like a tire) valve, so to use the Space Bags, I made an adapter using a tire valve stem and a PVC pipe cap. Once the vacuum is applied, the Space bag holds it pretty well. The bags are pretty thin, though, so avoid sharp corners on your workpiece.
 
One option I've heard some use is the compressor from an old refrigerator or air conditioner as a vacuum pump. You may be able to find one for free except for the labor involved in extricating it, and any parts needed for connecting it up.

The problem I've heard is that used as a compressor, the working fluid lubricates the pump. As a vacuum pump there's no lubricant and it can wear out relatively quickly. But relatively quickly for a refrigerator could be a very long time for a veneering vacuum pump.

I was meaning to try it sometime, as I have an old dehumidifier. But as I have not yet tried it, I can't say how well it works or how long it lasts.
 
Top