Thanks for the input. I think I will build a 3x6 table and use the existing table for storage and assembly work. I have space for a new table and would like one that I can walk arround. The existing table is built into a corner of the shop and I can't even reach the wall side of the surface, it is 5' x 10'. I can use the shop for just paying the heat and electric bills so I can't complain. I have about 650 sq ft to play in and a lavatory, and nice overhead lighting.

The original idea was not well thought out. I agree the 3/4" MDF will probably bend a little even with the Great Stuff leveling ability. I most likely could not squirt the Great Stuff on fast enough on such a large surface so that it would expand uniformly and stay soft enough to level it out.

Huck