After the ALICE Backpack Frame approach didn’t work out so well as a torso harness for the exoskeleton, I decided to go in a different direction and make a Kydex (very similar to ABS) mold of my back.
I then affixed the motor mount to this new custom molded back brace using aluminum stock and offsets created with Instamorph (super moldable thermoplastic you can get on Amazon).
First order of business was to make a plaster cast of my back that I could use to make the harness in Kydex. So I got some plaster cloth (or gauze). I got this one from Amazon because it’s nice and wide for the back. I would have gotten two rolls if I were to do it over as the first one went fast and left the back cast a little thin.
For making the cast, I laid on my stomach and my wife Christina applied the plaster cloth strips. A partner would definitely be recommended for this step! Also lots of vaseline and plastic wrap between the plaster and skin for easy removal.
Here’s the cast after the plaster had ample time to dry:
Next up was molding the kydex using the back cast.
To do so, I used a 12″ by 24″ sheet of kydex that was .93 inches thick (also available at Amazon).
To get the Kydex to a moldable temp, I put it in the oven at 325 degrees for about 15 minutes on a cookie sheet. The time is somewhat arbitrary and what you’re looking for is for the Kydex to easily fold over onto itself when lifting an edge.
After the Kydex cooled and hardened on the cast, I moved on to setting up the adapter that the hip motor actuator could be bolted using aluminum stock.
Next I made plastic hardware for the front of the harness also out of Kydex that would hold the velcro straps for securing the harness to the body.