: osb is cheaper, get the stuff used for sub flooring, (it is thicker than what
: is used for sheathing), and you will not have to worry about any
: deformation

Hi Matt

I wouldn't use particle board at all, as it really has no strength. It's basically a filler and used more in places where it stands on edge or spans very short distances. If you were wanting to keep it cheap and use the P.B. then use the harder stuff which we out here in California call " underlayment ". It is used in subflooring, and we use it inside some cabinet work, where it doesn't show. It is much more dense than standard particle board and is almost smooth to the touch. It mostly comes in thickness's of 5/8" and 1 1/4", so the 5/8" would be the closest. The problem with this stuff is the formaldihyde glue used to make it. Definitely don't want to be breathing it while you cut. It is also very heavy, and for that reason, would not be my choice for a strongback.

I would stick with plywood as you have more or less decided, and I would go with 3/4" rather than 1/2". Some on the KBbb have used 1/2" and found it to be a bit too flexible. However, most have just braced it a little bit more to make it work. I would just as soon go to the 3/4" and get away from that all together. If you want to go stapless, then use it on your forms also, and cut a groove around the edges for spring clamps to attach to Hope that helps.............

Rehd