Wood of all forms, with MDF being a preferred material
Hard plaster or ceramics are common for making molds
Existing products and hard plastic models can be great for bucks
Metals work great if you have something the right shape
Renshape, urethane modeling blocks, and molded epoxy are designed for buck use
3D printed ABS is preferred for 3D printed bucks
3D printed PETG for most commonly formed plastics (check glass transition temp!).
PLA can work but may deform. Use extra vertical & horizontal shells to sink more heat.
NOT soft plastics or Sculpy (they melt)
NOT wet clay/putty/etc (it squishes and drips)
NOT soft foam (they squish)
NOT hard styrofoam (turns out it melts into the plastic)
NOT anything crumbly or dusty (they make a mess inside the machine)
NOT wet clay (both squishes and makes a mess)
NOT potatoes (mostly just a waste of food, otherwise it is pretty viable)
If you want to use other materials or non-approved materials which do not endanger the equipment, send the area champions a quick email or message in the Discord for approval before trying.