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[Sensei]

A while ago, I made a custom ring for my girlfriend by designing it and having it printed in plastic at ponoko, a website that does suck things.

Anyway, some notable flaws with that first model were that it had a strong plastic smell to it, and collected dirt surprisingly fast (due to tiny gaps between plastic layers) which doesn't wash off well. I was thinking of making another, similar ring but coating it in something in something to give it a smooth, non-smelly washable surface.

So, I have come to ask, does anybody know what sort of paint or enamel one uses to coat jewelry that's skin-safe?

[LeoLeonardoIII]

I would suggest sanding the ring, buying a kit of room temperature vulcanizing rubber, making a mold of the ring, and casting the ring in resin or perhaps even a soft metal if the RTV rubber can handle it. You can capture good detail with the mold and it doesn't destroy the original so you're only out a few afternoons and some cash for materials.

I don't know of any lacquer that's specifically skin-safe, but I'm sure someone in B12 does! Good luck!

[acetech09]

A while ago, I made a custom ring for my girlfriend by designing it and having it printed in plastic at ponoko, a website that does suck things.

Anyway, some notable flaws with that first model were that it had a strong plastic smell to it, and collected dirt surprisingly fast (due to tiny gaps between plastic layers) which doesn't wash off well. I was thinking of making another, similar ring but coating it in something in something to give it a smooth, non-smelly washable surface.

So, I have come to ask, does anybody know what sort of paint or enamel one uses to coat jewelry that's skin-safe?

Hmm.

Spoiler: DISCLAIMER: Purely theorycrafted answer. Never done something like this before. (click to show/hide)

My standard response to 'I want something smoother and coated' is industrial-grade epoxy, but I'm not sure that would work. There are some popular adhesives that I know are skin-safe, but not sure how they work out as a coating.

That said, the only thing I can think of is an FDA CFR 175.300 M sealant epoxy with a high viscosity. Atom has a pretty good selection, I'd recommend this:

http://www.atomadhesives.com/FDA-Grade-Adhesive-Food-Safe-Epoxy/AA-BOND-FDA16-FDA-Grade-Epoxy-Adhesive-Medical-Food


Sand the wring, then brush/dip that on and hang it in the optimal position so it doesn't drip off.

Molding and casting like Leo said would also work, but I'm not sure how complex the ring is.

[LeoLeonardoIII]

I'd point out that you should test the enamel on something else to make sure it doesn't cloud up - especially if you saved some of the leftover material the ring was shipped with such as sprues etc. on the off chance there's an unusual chemical reaction. But also, hang the ring to dry in a way that makes the excess drip off of the detail work. Better to have an excess droplet on the side than right in the middle. Also you may need to break the ring off whatever you used to hang it, so consider using something like a thread rather than a nail.

[acetech09]

Not sure what plastic you're printing in, but if you can microwave it shortly without compromising structural integrity, briefly nuking it after applying epoxy would thin it out a bit and probably spread coverage a bit better.

Also, you can pigment epoxy. Just throwin' that out there.

[Sensei]

Also, you can pigment epoxy. Just throwin' that out there.

Interesting. I don't know if it's the right kind, but I have some epoxy lying around used for repairing model planes (it's a sickly yellow color when dry though). I'll have to look into actually getting some dyes that can be used in that way. Colored epoxy would be ideal, actually- that would allow me to use Ponoko's highest resolution plastic, which is unpigmented. I should also say, I'm not too interested in getting into molding/casting, which is a separate hobby of its own.

Oddly, I also can't seem to find information about epoxies that are skin-safe. The closest thing I can find is some stuff for making body molds, which isn't going to be kept on one's skin for more than a couple hours. There was another person asking pretty much the same question I am, but they seemed to go unanswered.

..further googling did find this which advises that A) most epoxies do not irritate the skin once cured and B) there are epoxies intended for coating as well as for adhesives (I have the adhesive kind). It looks like I should be able to just head to the arts and crafts store and look for some coating epoxy.

[acetech09]

Pigmented coating epoxy should do OK, but I still would be most comfortable with super-food-safe epoxy if I was making something for my own s.o.. The stuff I linked actually is a coating epoxy too.