This is a super simple project that has been a huge hit. Here's a quick overview. Check it.
Our nephew wanted a TechDeck half-pipe for his birthday this year. We thought we'd kick it up and build him his very own real concrete fingerboard bowl park. The goal was to create a unique park from materials we had on hand. At 60 lbs., this park weighs a wee bit more than our nephew.
tub/form (we used scrap 3/4" plywood and spray glued some plastic film to it)
spray silicone or some type of mold release
and of course, duct tape
Step 1: 1. Create the form
Create a negative mold of your desired park shape.
We built a tub from scrap 3/4 plywood and spray glued some plastic film to it. To create the bowl shapes, we used 1 larger wooden bowl and 2 smaller glass bowls. The transitions/gaps where shaped from a few chunks of styrofoam and duct tape.
Note: The mold needs to be smooth, so the concrete can release when cured.
We used caulking to make smooth transitions and rounded corners. Use your finger and a little water to smooth out generous beads/globs of caulking. Let the caulking dry overnight before pouring concrete.