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Discussion Starter · #1 ·
This last week-end, I built a really slick way of solidly clamping parts together for gluing, without using clamps or using heavy weights.

The idea was to remove air from a bag, and let the weight of atmospheric pressure, "clamp" together the parts.

In the photo below, is a Lazy Susan used for playing the board game Dominion. Yes we use a router to give all the edges a "rolled" edge. It is made of four layers of Baltic Birch, pinned together with dowels and stained. Since the Lazy Susan is 2 feet in diameter, and my vacuum can create a 14 psi vacuum, the effective clamping pressure is the same as having a 3 ton press on top of the Lazy Susan (note: there are two Lazy Susan's in the bag - the second one is on the back side.). This is similar to what folks who work with veneers do.

What is really nice about this, is that we now have absolutely no more marring of our stained finishes due to clamps pinching the finished surface, and the surface pressure is uniformly distributed across the entire face of the parts.

The white surface you see below, is a fleece fabric used over the Lazy Susan, to allow the air to move over the face of the Lazy Susan to the port, where the air is dragged from the bag to the vacuum pump - I am using a "Saver Bag" from Zip Lock, which has a "Zip Lock" reusable seal on one edge. That seal means the bag is reusable for many projects.

My wife is delighted with how easy this is for her to use.

You can see the final Lazy Susan product and other fun things we make at: LinnellDesign dot com

Total cost was about $200.00 and a Saturday to build it. The black transformer was used to step up my line voltage to 230V to run my surplus purchased vacuum pump - all the other parts came from Home Depot.



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Something like that would take up way too much room in my shop. I don't need one anyway, clamps of one sort or another, or a weight, work just fine for me. Actually, it wouldn't work well with what I make anyway, and would take way longer for me to set it up than just using a weight.

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Discussion Starter · #7 ·
There are several YouTube videos describing how to build these.Look on YouTube for: “Making a Vacuum Pump System: Andrew Pitts ~ FurnitureMaker” or “Homemade Vacuum Press” .

This one is good too: “How to Make A Vacuum Bag for Veneering”. <-- maybe less expensive than my system...

Check out JoeWoodworker dot com. You can get good advice here.

These examples are quite nice, but are kind of expensive…

I’d give you the URLs, by the forum does not allow me to until I have 10 posts… ☹

What do the parts do:
The pump sucks the air out, the white cylinders keep the pump from short cycles of on/off, they do this by providing a volume of space which must be filled with air before the vacuum level falls low enough to cause the vacuum switch (located inside the electrical box). Without these, the only air volume is in the tube, which is not very large.

The gauge indicates the amount of vacuum in the system. The electrical switches: the bottom one turns power on/off to the pump, the top one disables the vacuum switch from operating, which implies the pump will run non-stop.

The black box, is a 115VAC to 220VAC transformer. When I bought the vacuum pump, I got it really cheap, only to learn it ran on 220VAC. The transformer bumps up the voltage so that I do not have to run a 220 line to it.

The box below the transformer is a a capacitor to start the pump motor.

There are two valves used, one to isolate the pump from the rest of the system, the other prevents the vacuum from reaching bag. These were useful to find leaks...

To build one: you will need:
A vacuum pump (ebay is your friend).
A Vacuum gauge (get one which will go down to 30 inches of mercury).
If you wish to run the system at less full vacuum, a vacuum switch (find part number F-4200-X30-PM from Airtrol) is really handy. I want to built RC airplane wings from foam, so I need one else I’ll crush the foam.
A couple of pieces of 4”” pvc pipe with end caps.
To connect Home Depot ¼ inch plastic tubing, use these: SMC KQ2H07-35AS Brass Push-to-Connect Tube Fitting with Sealant, Adapter, 1/4" Tube OD x 1/4" NPT Male
The bag I use, was found at UHaul, made by ZipLock for use with a vacuum cleaner.
The vacuum bag connector I bought from www compositeenvisions dot com ($19.99 in store price).
In the bag, you need to place some felt to allow the air to escape the bag – or use an old towel.
From the vacuum pump, I feed the vacuum through a brass shut off value, then to the vacuum gauge, the vacuum switch and then to the two PVC tanks and the line to the bag.
The reason you need the tanks, is that without them, the vacuum pump will cycle on and off often once the vacuum switch detects sufficient vacuum is present to shut off the vacuum. Mine were made from a 2 foot section pipe, cut in half. The tanks are connected together through a “T” brass fitting with a connection to the bag.
One of the on/off switches powers the vacuum pump, the other shorts out the vacuum switch, causing it to run the vacuum all the time.

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