Gasketed Plenum

[thewoodcrafter]

My bleeder board was getting pretty thin so I decided to to replace it. Found more saw dust under it than I could believe.
It was time to re-do the table. I surfaced the plenum. Was out about .025". Dug out my Allstar gasket material I bought about 2 months back and cut a channel around the outside edge and in between the 5 zones. Squeezed the gasket (no glue) into the channels and put a new bleeder board down. The new board had to be lowered down in the right place because it would not slide on the gasket. Surfaced both sides of the board and ran a small job.
What a big difference. With no material on the bleeder I get no gauge movement with the blower turned on. Adding a sheet of melamine the gauge goes to about 14" and just starts popping the safety relief valve. Big improvement.
I do not have any glue or screws holding the bleeder down and I do not see any warping of the bleeder after 2 re-surfaces.
I would highly recommend a gasket under your bleeder. It makes a big difference in holding power.

[wayne_walker]

Roger,

How thick of gasket material did you use? Did you cut the groove half the thickness of the gasket material? How wide of material?

Thanks in advance!

Wayne

[thewoodcrafter]

The material is .25" x .312" I ran the channel with a sharpened .25" bit, so it is a little under .25"
The gasket sits above the plenum about 1/32". You want just enough to seal but will crush to the plenum surface with suction on. You don't want too much gasket above the plenum because your spoil board will move around if the gasket is holding the board above the plenum. I now have to make sure I Z zero with the blower on.

[Gary Campbell]

Wayne...
There is a couple pictures and a little more info on using this same gasket here: http://www.shopbottools.com/garysmusings.htm
Gary

[scottbot]

Hey Roger,
Thanks for sharing your findings.
That sounds like a good thing to do.
I think I'll be adding that to my plenum soon.

Scott

[wberminio]

Gary

With your setup-when you cut full sheets- do you leave you smaller bleeder sections and place you
full panel on top or do you use a full size bleeder?

BTW-I really enjoyed your new articles.Looking forward to more!

Erminio

[Gary Campbell]

Erminio...
Thank you for your kind words.

Our T track is about 1/4" above the plenum, which keeps the bleeder from moving while cutting. This also means that we can only use the quadrants. We have only had a couple instances where a bowed partial sheet wasnt held flat due to bridging the T track and only having a small amount of coverage on the adjoining zone. The material is then deemed unfit for use.
Gary

[wberminio]

Gary

I made my plenum similar to David Buchsbaum's.I placed my bleeder on top and held it down with gorilla tape along the edges.Works fine except,it's not so convenient to remove and use the tracks.
I'm always open to was to improve on what we have.

Erminio

[wayne_walker]

Roger,

Thanks for the specs. on the gasket material and application. That looks like the way to maxamize the vacumn.

Gary,

Thanks for the link. Great information.


What a great forum!!

Wayne