oriented strand board

I was wondering if anyone has ever made a rack out of this board? I am making a rack for 67qt tubs so it will be 44" by 24". will this stuff sag?

You don't want to use that stuff, it will handle humidity better than particle board, but like particle board the glues used to bind it together can be very toxic especially when heated. The best wood based material to use for a rack is melamine as it has a veneer of plastic over the wood. Hardwood plywoods are also a good choice, but eh best choice is Plastic sheets. See if you have a sign shop local to you, they usually have sheets of plastic available.

ok thank you, i will go with melamine.