Bending sheets of plywood

Kerfs and/or laminate thin sheets.

I saw a couple shows on TV where they built those. Including one on a back of a truck on Monster Garage!

Seems to me, in both cases, they went to their local lumbar yard and ordered some kind of special plywood designed for this sort of thing. It was expensive but was designed to bend. Seems to me that it had a special kind of surface as well.

Talk to your lumber yard. They may know about it.

And the skateboard folks should know about this sort of thing. Probably not many skateboarders in this newsgroup!! It IS hard on the arthur-itis.

You should try posting a parental message in a skateboard group sometime. :-) The responses are the closest thing to having a colony of bees living in your head, dude. :-)

If you don't want the expensive special skateboard wood, you can always use wacky wood. It's designed to bend, but it doesn't have the special surface. Probably not strong enough by itself, but if the option is that or nothing...

Then try google.

I built a quarter pipe for my son years ago. As I recall it was about 4' radius, but more gradual on the approach. I mounted one sheet of 1/4" ply that had shallow kerfs cut in the back. Then kerfed a second piece and glued it to the first. Both were attached to the frame with screws. Use wood screws, not deck screws. These things take a beating and a fair amount of torsion.

Also helped a neighbor build essentially a half pipe in a similar manner (two quarter pipes attached with about 4 or 5 feet of run-in.

If he doesn't have them yet, I STRONGLY recommend your son get helmet and pads. These things will hurt you. And splinters..........Ohhhhh!

I'm getting into this a little late, but are you famaliar with bending plywood?

Usually poplar, usually 1/4", quite common for bars, decorative curved pieces, etc.

Any decent plywood house will have it.

HTH

Lew