Uneven table

[bleeth]

Yellow glue works just fine. Not sure I would want to use polyurethane due to the way it foams up and expands as it cures.

[davidp]

I stopped gluing my spoilbaord to the vacuum plenum about 5 years ago and most of my problems disappeared with the glue. Keep your plenum dead flat and when the spoil board get chewed up resurface it then flip it over.

A flat table is the best thing you can do for your cutting.

Experiment and work out the best solution for you

David

[fozzyber]

Brady , I hate you.

I have the same problem and I did not glue my plenum down, just redid my spoil board too..

DAMN.

"Screws are bad news"

Your spoilboard 'layup' should consist of the following:

1) A good quality layer of plywood bolted to the steel crossmembers. This is your support board.

2) A sheet of Medex or MDF GLUED to the support board with wood or Gorilla glue. This is your vacuum plenum layer that you'll machine the zoned grid into.

3) A sheet of Trupan or Ultralight MDF GLUED to the plenum layer. This is your bleeder/spoilboard.

If you have screws on any layer, the material WILL buckle & you will be plagued with unreliable flatness in your table until the end of time. The ONLY way to remedy this is to rip it all off & start over. I have seen this problem over & over again...

-B

[Brady Watson]

Brady , I hate you.

I have the same problem and I did not glue my plenum down, just redid my spoil board too..

DAMN.

I too have hated myself in the past for not gluing! Now things stay really flat and consistent. I never need to shave off more than .04" on my spoilboard...I can't say that was always the case. Them early days were ugly.

There's nothing stopping you from pulling it apart by removing screws, then glue & clamp the whole deal back together again.

-B

[dauteuil]

Should the vacuum been on when glueing. Say an hour or two?

[bleeth]

Absolutely-Or cover it with some good weight like a bunch of cement sacks.
(That would be "IMHO").

[fozzyber]

just ripped it off, I cant unscrew it because the screws are in between the bleeder and plenum. damn damn damn.

OH well, time to do it right this time.

Brady, I don't really hate you, just want to shoot the messenger

I too have hated myself in the past for not gluing! Now things stay really flat and consistent. I never need to shave off more than .04" on my spoilboard...I can't say that was always the case. Them early days were ugly.

There's nothing stopping you from pulling it apart by removing screws, then glue & clamp the whole deal back together again.

-B