Sacrificial Workbench Top?

[John TenEyck]

Bill, you didn't say how large the table needs to be. The bench I showed above is a piece of lab bench top under the Masonite, 32" wide x 8' long. It has stayed flat for 25 years, and is the bench I use for vacuum bagging. A solid core door would do just as well if large enough to meet your needs and you would be done yesterday. Nothing wrong with a torsion box, just that it takes time to build. And FWIW, I had my RAS bench top out of two layers of particle board, skinned with Masonite, over 20 years ago, and it is still flat and true. If you have adequate support under them composite panels are fine. If you welded a couple of additional cross bars to your frame I'd have no hesitation using it with a layered composite top.

John

[andy bessette]

You don't need a torsion box. But you do need to add some cross members to that bench support.

[John Sanford]

What Andy said. Add 1 or 2 cross members. The cross members would also make using MDF more practical. Doubled MDF, and then some Masonite on top that can be replaced.
You'll likely find yourself using the bench for more than just vacuum bagging.

Fine looking bench frame btw.