How to make hollow silicone parts

Created by b0baganush on Sept. 14, 2019, 9:58 p.m.
  • I work in a medical research lab and we are doing work with aneurysms. There are soft silicone practice models available (see attached picture) but they are quite expensive. I would like to try and make my own for our lab but I am not 100% sure the best way to go about making hollow silicone parts like this. I found this Formlabs forum post ( which seems like the way to proceed but there are a few questions/concerns that I have:

    1. I would need a removable core to make the part hollow but as you can see the models can get quite complex and large so what would be the best way to remove the core without tearing/destroying the molded part?
    2. Is there another silicone molding process that I could use? I am only familiar with basic molding techniques.
    3. What type of silicone should I be using for making the part? (i.e. basic off the shelf, specialty silicone, etc.)

    I have an SLA and Polyjet 3D printer at my disposal to make models with. Any advice or direction would be greatly appreciated. Thanks!

  • This is not something you can cast in RTV silicone without creating a seam that may be of questionable strength. Medical grade silicone is not generally sold in small quantities, some kind of extrusion process would be necessary to produce the tubes reliably and the equipment involved in all of this is not going to fit in a garage. The expense of the practice models is likely justified.