"Cheat" to flatten wood

[Andrew Seemann]

A 1/4" sag or bow over 7 feet is nothing. You could run it across a jointer, make it flat as a surface plate, and come back two days later after humidity changes and it could have a 1/4" sag in the other direction. Just alternate the rings as mentioned above and biscuit it together. The biscuits are only for alignment. Dowels will work as well; biscuits are easier and more forgiving. Keeping the board width under 6" is probably a good idea as well, and will work with your 6" jointer if need be.

Glueing to mdf, might work if you live in area with very little change in humidity year round, but in 90% of North America, it likely will lead to problems.

[Mark Bolton]

Have you used an epoxy resin with bad results? And no, I'm not planning to float it down a river

Why would you have to have used it and had bad results?

[Will Blick]

when making a wood top with resin or epoxy, wouldn't MDF with glued thin laminate on it, a better option vs. using thick wood, which certainly might move.
I have seen bar tops that are 50 years old buried in some type of clear resin or glue, and never noticed any problems with movement, so I assume it must be done with success.
I would contact the resin or epoxy makers, they prob. know would offer better insights...