Aerotech 29mm and 38mm Rocket Motor Casting Tools

Update (2025-01-26):  Added new models for easier clamping.  AT XXmm Casting Tube To Base Holder files are used to hold the casting tube to the base with fewer clamps.  Take a look at the pictures to see how I use it.

I use these to cast sugar motors for Aerotech 29mm and 38mm rocket motor hardware.

Hose clamps are used to hold the two casting tube halves together.  I've used Velcro straps before, and they are fine but have to be tightened for each casting.

For the coring rod, I use 3/8-inch Delrin rod for 29mm and ½ inch Delrin rod for 38mm.  The clamps are regular Quickgrip style clamp.  One or two clamps to hold the casting tube to the bottom piece and then another clamp to compress the fuel.  You will probably need to print extra Top pieces, so the compressing clamp doesn't touch the coring rod.  I made some 50% as tall top pieces to help with this.  See the picture for how it goes together.

I use cardstock paper for my grains.  Below is the size of paper I use for each size and the weight of the paper.

For my mold release I use one of two things, regular olive oil cooking spray or Stoner.

No supports needed.  Printing at 0.3mm layer height and possibly larger is just fine.

Print material:  PETG is working for me with a decent amount of infill.  ~60% on 38mm casting tube.  Otherwise, the casting tube will warp/deform from the heat of the sugar and your grain won't fit into the liners.  Other materials (i.e. ASA/ABS) may work with less infill but haven't tried it.

I buy liners, insulators, nozzles, etc. from Aerotech (RCS, parent company).  For 38mm, there's a print for a liner cutting insert.  I use a pipe cutter to cut the liners and to make the liner rigid, I put the insert into it.

https://www.rocketmotorparts.com/