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View Full Version : Adhesive used between plenum & spoilboard?



myxpykalix
09-17-2006, 02:10 PM
Ok I did my homework by searching the archive for this question but couldn't find the answer. I know you are supposed to shellac the spoilboard and plenum board but do you use some type of adhesive to glue them together? if so, what? Is there places reserved in the cutting of the plenum that allows you to drill holes to secure the plenum board to the plywood? I bought some nylon toilet seat bolts to secure plenum to plywood and I assume you glue spoilboard to plenum so there are no mechanical fasteners to tear up your bits?

Brady Watson
09-17-2006, 10:01 PM
I use wood glue & my brad nailer with 1.25" 16ga brads to tack it while the glue dries. The brads are so small that carbide cutters deal with any little bits they encounter. You can also clamp it down if you have a lot of cleamps and lots of weight for the center. Running the vac while things kick helps. Don't use silicone...it will pop up after a while.

-B

mziegler
09-18-2006, 11:45 PM
Most brads are soft metal that router bits can just buzz right thru them. Sometimes brads break off when I remove parts from table or break off when pull out of the table. I just hammer them back into the table. Knock on wood but I hadn’t lost a router bit yet to a brad. Mark

jhicks
10-01-2006, 10:12 AM
I just completed a new vac system and will post some photos shortly BUT our technique was as follows.
1) Level the top/ base board in 3/4" MDF.
2) Cut zones with 1/2" ball bose 1/4" deep to eliminate sharp corners in vac plenum channels and produce better laquer seal all around.
Each zone is 1' x 4' and has a waffle iron type grid with 3/4" square full heigth squares and 1/2" x 1/4" deep ball bose grooves which all join to the zone vac 2" PVC input port. Each is independently controlled with shut off valve. 8 valves total to zones plus 1 for each vac, plus 1 to connect between each side or shut off.
3) Laquer entire base board. Took over a gallon for 5 x 10 table and make sure all corners, edges are coated 2 coats min.
4) Cut 1/4" groove with 1/4" end mill around the edges of the zones .020" deep to be used for outer gasket seal on each zone.
5)Place Allstar Adhesive gasketing .062" x .25"in the 1/4" grooves.
6) Lay up a top spoil board made from Ultra Lite trupan. Didn't need to surface yet but will after a bit of use.
The laquer did cause the MDF to swell a bit and create some doming but once Trupan is leveled and the base board settles in a bit It will be dead on just by surfacing the trupan as required.
Besides the plumbing and valve system this is it.
Trupan holds very well and can be easily replaced or resurfaced as needed. No screws, plastic nails or anything to hold it to base board except the vac. and the gasket tape which creates some nice lateral resistance against the trupan sheet sliding anywhere.
When used on a 3/4" sheet of Chipboard for a counter top, on top of the trupan spoil board, then placing the formica on top of thew chip board to cut it, everything held great and delivered excellent, chip free edges for counter top cut out and edge banding.
After formica was cut a bit over size for final assembly and edge finishing, the chip board was held and cut on the vac table just where it was and also turned out excellent. Then under edge material was cut in 13 ply sheet for the underside added thickness and edge support. Once all was cut its assemble, glue formica, and finish edges. perfect.
No nails or bolts required and they maye even be a detriment as vac levels spoil board evenly to base rather than ripples in screw or nail areas.
Using zones which allow for a wide variety of sheet options and 2 shop vacs. 1 is an old sears 5.5HP and one new rigid 6.5HP. Each can be run independantly or together depending on the zone set up required.
Have since run prefinished maple ply and melimine cabinet parts. Drilled 5MM holes for shelf and drawer mounting and cut sideds with compression bit. PERFECT shape, dimension, holes, and no chip either side anywhere!.
I never believed shop vacs were the answer but now I wonder what I was waiting for. Its great!
Cost for the set up ran around $350.00 without vacs and is worth every penny to slap it down and run vs nails, screws, fences, or whatever else one can hold with.