In building my vacuum table instead of buying miles of weather stripping to seal pieces to the vacuum table, I tried a rubberized paint in the roofing section of hom depoe, it has rubber particles in the paint. 2 coats on the pvc sheet and on tempered hard board did not hold a vacuum. 2 coats were better than 1, maybe 5 coats will make a thick enough layer but the problem with 2 coats was getting perfectly even and consistant coverage. Double stick tape worked great even with leaving one side with the plastic layer on it so it didn’t stick to both pieces in the test. Stuck it to the platen and left the red layer on (so used only one side with the sticky) so not to stick the template to the platen. Pulled 10 " vacuum (about max for my old pump).
I will be using one side of the double stick tape to hold the vacuum platen to the slotted board (just in case I need to remove it) and one side of the double stick tape on the top side of the platen so I won’t need any “sealant” on my many template panels. I have alignment pins to hold everything aligned until I engage the vacuum and all should be fine.
The rubber weather stripping is the best except the glue wears off quickly and I don’t believe it will hold up to the many changes of templates it will see.
When blazing a new trail, sometimes the ground can get a little “burnt”, when following a trail always be alert to smoke on the horizon. Jude
What about painting the outside too so the rubber gets puled by the vacuum and pushed by the atmosphere into the board under and not pulled off it by the air coming through it…and butyl rubber tape as the removeable seal…Probably have to seal the back of your wood stock too.
Did put the painted side up to pull vacuum against it but still could not get a seal. painted both sides seems to be good idea but the painted side down didn’t work even on the pvc which doesn’t bleed air. butly rubber tape??? is that what the double sided tape is or different tape? Once I seal the vacuum top panel (which has holes to hold the template, I will seal the template (2 pieces of hard board contact cemented together) to the vacuum top with the tape on the edges and in interior spaces. The template will have tape on the topside for the stock to seal against. The stock (mostly plywood panels ) I will need to seal with probably varnish (any staining first) and any artwork engraved into the pieces will be ready to color with the varnish protecting the main part (multi coloring the parts). This gets involved, and will become a tutorial once I have the process complete and am cutting production toys. I will have a 16" x 14" vacuum table pulling vacuum over that whole surface and any bleeding will disrupt production so thanks for the wood stock seal tip. Right on and I feel we’re alm ost in this together. Thanks YoMan. Jude
found it: Fabral
1/4 in. x 40 ft. Butyl Rubber Sealant Tape
4.5 out of 5
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Questions & Answers (13)
Designed to protect Fabral metal roofs
Exceptional seal creates a waterproof barrier
Maintains elasticity and adhesion in all weather conditions
$4.98 /each
I’ve found the vacuum stripping that is sold at veneersupplies works extremely well and is reusable. This stuff http://www.veneersupplies.com/products/Vacuum-Gasket-Tape-For-Clamping-38-x-18.html. I’ve peeled it off and stuck it on another setup, and it works fine. While wandering around Lowe’s today, I found a nice thick piece of rubber about an 1/8 inch thick about 4x5 inches. I haven’t tried it out yet to see if can be used as a vacuum seal. It seems awfully hard and I think a seal needs to give some to seal properly.
Because I have a weak Gast pump (.4 cfm), I couldn’t do the full table. But I can do vacuum pods. I made my first production run today of some cribbage-board-style scoretracks I provide with the gameboards I build, and a 3x4 inch pod held a 3 1/2 x 5 piece of 1/2 inch plywood at 22 inches of Hg without a problem.
Wouldn’t a small pump just take longer to pull the vacuum, it’ll pull .4 cf just seems like there can’t be much more cubic feet of air even in a full size vacuum table. Once the vacuum is pulled there is no more air to pull, shouldn’t it hold it??? My vacuum pump needs new seals so runs continuously but still holds 10 + inches of vacuum. Just wondering… Jude
I believe this is true. The issue, I believe, is how well you can seal the table and the openings that are not covered by the stock you want to mill. A higher volume pump is more likely to tolerate those leaks than a small volume pump. With a small pump, the pod scheme seems the most efficient