Rock and roll bed platform plinth.

[triggermala]

What wood is everyone using to make one of these platform boxs. Birch plywood is very expensive.

[cobblers]

Any plywood would be OK, but cheaper stuff is more flaky and less dense so would need more care in finishing.
OSB/Chipboard is trash,and MDF (unless special water resistant stuff) is not really suitable for long term automotive use.

[triggermala]

Thanks everyone for your help and advice, it's much appreciated.