Last year, we (5414) used silicone tubing on polycarbonate tubes as a roller system for our intake and claw. The process for actually getting the silicone on the roller involved a lot of dish soap and effort, so this year we printed a jig intended to help the process go more smoothly (and less soapily). This is especially useful for making 2” rollers, since the largest silicone tubing sold by McMaster is only 1-⅜” ID.
The jig is available here. Here’s the process we used.
First, plug the end of the tube. Depending on your printing tolerances, you may need to use electrical tape to get a good seal.
Cut the silicone to the proper length. It should be about 6 inches longer than you need. Put the silicone over the sleeve, and put the sleeve over the tubing. It may help to use masking tape to get the perfect seal
Put the other end of the silicone over the adapter (for the compressor nozzle).
The two ends of the tube should look like this:
Finally, it helps to put the entire assembly within a larger tube. This stops it from “ballooning” and lets you fully inflate the tube. Here’s a video (without using any dish soap):
To make your life easier you can get silicone the exact diameter of the tube. We just compress air this on now. Well add more diameters and sizing by request.
I’ll get a video of it the next time we do it, but we found great success by using some larger PVC tubing in a T shape and a vacuum table we have for investment casting (the metalshop does jewelry making with it). The vacuum pulls the air in a way that stretches the silicon tubing to the inside of the larger tube, we slide our roller tube in, and stop pulling vacuum, and it conforms to the roller. Sometimes we need to stick a welding rod in to let out an air bubble.
Obviously most people don’t have a vacuum table, but I’m pretty sure you could get similar results with a shop vac.
