I recently completed a batch of R2D2 horseshoes. These go on the outsides of his shoulders. I've gone through several designs and techniques. What I've settled on here is a single piece of 1" thick MDF. I've routed out the detail pockets in the front, then I rough out the shape on the tablesaw and bandsaw. Then I round the curve and finish the sides with the belt sander. Finally, I use the router with a 1/8" x 1/8" groove router bit to cut the shim on the back and then the grooves along the inside. The process is elaborate and it all has to be done in just the right order with jigs and so on. I've tried PVC layers, MDF layers, and several designs, but this is definitely giving the best results. I've got several pairs of these for sale for interested builders. These are perhaps the most complicated pieces on the droid besides the feet and they will consume a lot of time and resources, so I think this is a bargain at $85 a pair.
Here's the back showing the shim:
And the front with the pockets:
A closeup of the inside grooves:
The shim from the outside:
Another shot of the grooves and pockets:
The club officially authorizes periodic runs of aluminum parts, including these horseshoes. In order to make it worthwhile, there needs to be enough buyers to do a large group of them. Aluminum horseshoes are much more expensive--usually around $225 or more. If you want aluminum, I encourage you to go that direction and help make the machine shop runs possible. I've built these horseshoes for builders who do not have the budget for aluminum and who are not able to do the sort of construction I can pull off with my shop.