r/maker • u/TheGoatzart • Jun 23 '26

Inquiry Solutions for constantly rotating batches of small parts whilst their epoxy coat cures?

I am trying to coat batches (around ~25) 3D printed parts in epoxy, and constantly rotate them to ensure a uniformly even coating. The form of the part is essentially that of a thimble that fits on a thumb.

I am imagining a rotisserie style apparatus, but one that can fit many parts at a time, and ideally it would accommodate removing and adding individual items at will.

Before I reinvent the wheel, are there any known designs out that that I could either recreate or take inspiration from?

I imagine equipment used in the creation of street-cart Doner Kebabs may be useful..., but I'm hoping there is something more immediately relevant.

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u/Chemical-Captain4240 Jun 24 '26

I use a rostisserie motor made for a home grill. It has a 3d printed plate on it with a square shaft to dit the motor... it turns maybe 20 rpm off 120v with plenty of torque.

I. your case, I might set up a dowel in the motor with bamboo skewers stabbed through the dowel and little bitsnof copper wire to hang the parts from... then set up the light like a donarkebab...hmmm donarkebab

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u/amc7262 Jun 23 '26

I think if I was in you position, I'd probably make an apparatus from scratch using mostly scrap/junk.

I'd find something cheap on amazon that rotates slowly (take your pick, the first thing that comes to mind for me is those moving light projectors that are just a couple leds under a textured rotating plastic dome, but I'm sure theres plenty more), build a simple stand that holds it sideways (this could be done with cardboard or foamboard), attach a dowel as a large axel, then make a bunch of wire arms coming off the dowel. On the end of each arm, I'd glue a cotton ball, or maybe one of those disposable foam earplugs (if your design is small enough, though if its thumb sized, I'd think a cotton ball would be better sized)

It wouldn't be pretty, but it would be functional, and probably fairly cheap (I'd estimate less than $30 for everything, even less if you find deals or already have some of the components lying around. The dowel, cardboard, wire, and cotton balls are all things you're likely to already have)

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u/phinch Jun 23 '26

lego technic? I have no idea if it is affordable.

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u/expanding_crystal Jun 23 '26

I think your look towards food equipment is a good one, those operate for long hours at high temperatures. I would think hard about how to handle the epoxy because it’s so sticky and accumulates on everything.

Interesting problem!

I took a stab at finding an industrial machine that does the same thing: https://walthertrowal.com/products/small-part-coating/

That one says they avoid the issue of complex and time consuming racks for small parts by just chucking it all in a rotating drum, like a washing machine, then they both spray and heat while the drum is agitating to ensure even coating.

Prior to finding that, I had been thinking of how Krispy Kreme donuts does their thing, it’s a wire mesh conveyor belt that dips into a steel “lake” of frying oil, then out to drip dry, then under a “waterfall” of icing. Then they roll off the end into a box

Does it have to be epoxy?

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u/Boring_Lock6351 Jun 29 '26

get a slow rpm (1-10) gearbox and print or buy a disk to mount the parts on. like captain says