SETTING UP A NEW VACUUM TABLE

[johnnny_b]

WE ARE SETTING UP A ALPHA 96 SHOPBOT HERE TO MAKE BACKS FOR OUR CABINETS WITH HOLES DRILLED OUT FOR THE DRAWER HINGES, AND THERE WAS BRIEF INFO ON HOW EXACTLY TO SET UP THE VACUUM TABLE... IS THE VACUUM BOARD CONNECTED TO THE V CHANNEL ON THE TABLE AND THEN MACHINED WITH ALL THE GROVES, THEN THE SPOIL BOARD ON TOP OF THAT FOR THE SURFACE TO USE TO WORK ON? WHICH FILES SEEM TO WORK BEST FOR THE VACUUM SETUP? WHAT THICKNESS ARE BEST FOR MY APPLICATIONS MOST OF THE MATERIAL WE WILL BE WORKING WITH WILL BE LESS THAN 3/4" AND MOST BEING < 1/2"? IF ANYBODY HAS SUGGESTIONS IT WOULD BE GREATLY APPRECIATED, WE FIRED THE GUY THAT WAS PUTTING THIS PROJECT TOGETHER NOW IT'S IN MY LAP... THANKS AGAIN FOR THE HELP

[Brady Watson]

John,
Here's a quick breakdown of the layers to a typical vacuum system, starting from the metal frame up:

1) 3/4" birch or quality alternative plywood. This attaches to the metal frame via carriage bolts.

2) 3/4 MDF or PVC (Komatex, sintra etc). This gets glued to birch base with wood glue, or PVC sheet gets scuffed with 60 grit paper, and gorilla glued to birch. This is the board that you will machine your grid into using a regular old 1/2" straight bit & vac SBP file you can find (AND PREVIEW 1st) in C:\SBParts\Vacuum. If using MDF, you should seal it with polyurethane after machining grid to eliminate vacuum loss.

3) Bleeder board/spoilboard. This layer *must* be either Trupan Ultralight or LDF (low density fiberboard). Search this forum for resources. This layer gets held to the previous sheet using vacuum. Flatten one side using the CR command to break thru the paper skin. Then, apply wood glue to the raised vacuum zone walls & perimeter walls around the table. Place flattened side down & turn on vacuum. After 1hr in warm temp, flatten this side.

You are now ready to use your new vac system. When bleeder board gets thin from flattening, flatten down to top of grid & replace with new sheet repeating #3.

-Brady

[bill_lumley]

I am also building my first vacuum table and have a few questions :

My layer 1 is MDO bolted to the frame .
My layer 2 is 3/4" MDF I was going to screw to layer 1 from the bottom after milling the plenum in Layer 2. Any problems with doing this ?

Does the Bleeder need to be glued to the plenum layer ? Does the glue stick to the pulyurethane coating ?

Thanks Bill

[paco]

Hey Bill!

Screwing either the bleeder board and/or the plenum will eventually bump as you surface it. I have screwed it before and this time I'm gluing it; it wont bump or raise at the corner and such.

Plus, the Bot as to dig 1-1/4" before hitting and screw.

I wouldn't recommend gluing on on paint of any kind.

[walnutman]

Hi Guys
are there any special or different cutting files available for the diffenent set ups of the plunum board. i.e for 2,4,6.... zone systems?

[walnutman]

Does anyone know if there is step by step procedure for seting up and installing a vacuum table system. I think I have learned what I need to know from surfing the forum, but want to be sure I approach it the correct way. Im just wondering if there is a well written detailed manual of sorts expalining the process from start to finish?

[Brady Watson]

There is an installation manual that comes with the vacuum system when you buy one of ShopBot's systems. Other than that, I don't know of any.

-B