I purchased a patty maker that didn’t fit my stuffer. I 3D printed a collar and adapter to make it work. (https://www.thingiverse.com/thing:4370508). Surprisingly enough, even printed in PLA, it’s held up pretty good.

Just be aware of the food safety issues with anything 3D printed in contact with food. There is really no way to sterilize an FDM printed item. SLA printing might be viable, but I haven’t researched food safe resin. You might be able to 3D print and then epoxy coat to seal the print.

I printed an adapter collar for the patty maker to fit on my LEM stuffer. It holds the faces of the horn to the output of the stuffer, so isn’t in contact with food. Used it last weekend to do 40 pounds of patties. I did the as above but I vacuum seal 4 patties to a pack.

PETG is not soluble by acetone, only ABS. There are solvents for PETG, but they are pretty nasty. The issue is not really “safe for food contact” but can it be sterilized. A 3D printed single use item is fine. I’ve tried to print air tight vessels and realized just how porous 3D printed items are. You end up with juices and fat pushed into the pores, which then collect bacteria, which then contaminates the next batch.

Are you looking for temperature control or smoke element control? If you’re going for temperature control, look up solid state relays and PID controllers. A little bit of work, but you can hold very accurate temperature.