Quote Originally Posted by cueball
Go with the 3/4 material for sure. The next size down is 5/8 and will give your problem with assembly and sag over time. Pre seal/paint your parts before assembly and the apply second coat once assembled.

An easy meathod to make straight cuts with a circular saw is to clamp a straight edge to the material and use that as a guide for the saw. The down side of the mel will be the clean cut. Mel is such much nice to work with because there is not further finish that needs to be applied. Good luck
To add to that.

Make sure you use plenty of supports depending on how big your rack is.