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There are only a handful of tools available to the average woodworker that can make an immediate and substantial difference in the quality of a finished project. A good miter saw, a classic router bit, or a fine hand plane; each of these tools can help turn a pile of lumber into a better display of craftsmanship. A vacuum press is no exception.
A vacuum press gives you the opportunity to use some of the finest woods available. Many of these species are so rare and valuable that they are unaffordable in solid lumber. In other cases, the wood may be too unstable to use in lumber form. By veneering those types of logs and burls, wood movement is controlled by the adhesive and a substrate like plywood or particle board.
Ultimately, the question is how to get the wood veneer to cure flat on the project panel. A vacuum press does the trick and now it does it easily and affordably.
After a year and a half of serious trial and error, and another year of updating and improving, I offer this free plan for building a vacuum veneer press. Make no mistake... this is a heavy duty, durable, and reliable piece of equipment. If you follow the instructions carefully, the press will last for as long as you enjoy the art of veneering.
Most
of the veneering books and articles I have read are just too complicated
and are geared toward proprietary materials and equipment. The
construction method found in the JWW vacuum press article uses
standardized parts that can be found on the Internet and at your
local hardware store.
I
wrote this article to show that you don't need a mega-buck
setup to build a professional-level veneer press. I hope you'll agree.
I'm always looking for a way to simplify and improve the system
which is why it's under continuous revision. As always, you are
most welcome to send me email with your suggestions for improvement.
The
Basic Idea
Imagine a giant Zip-Lock bag with a piece of plywood and an exotic wood veneer inside. To adhere the veneer to the plywood you need two things... glue and clamping pressure. The glue is placed on the plywood and the veneer is set on top. The panel is then placed inside the bag and the air from within the bag is removed with a vacuum system.
Vacuum
can be achieved in either through the use of an electric vacuum
pump (diaphragm, piston, rotary vane, etc.) or with a pneumatic device
called a venturi. On the following pages, you learn how the
differences between these pumps affect their use in vacuum veneering.
In
either case, a pump or venturi is rated by its air flow (CFM or cubic feet per minute) and the maximum achievable vacuum
level which is usually referenced as a measurement of "inches of
Mercury" or "inches of Hg".
A
vacuum press is a very powerful tool that is capable of producing
over 1700 pounds per square foot of pressure at full capacity. The
actual formula is 1" of Hg equals 70.56 lbs per square foot.
Atmospheric
pressure is what makes a vacuum veneer press capable of such incredible
strength (learn
more here). When
vacuum is applied, atmospheric pressure bears down with exponential
force. Not only does this press the veneer onto the substrate,
it also compresses the fibers of the materials being glued. As
the fibers are compressed, the air inside of the materials is
displaced with glue and within an hour, a bond is made.
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