Food Safe Resin/Casting Material?

[samiamuc]

I recently got the The Hobbit AUJ chronicles of design book. Looking through the sketches, I really like some of the designs, especially the designs for Thorin's cutlery. I want to make these for myself and I thought the best way would be to cast them. I'm sure that ordering them cast in metal would be far to expensive, so I was thinking of going with resin. Unfortunately, I'm not really sure of a completely food safe resin to use. It will need to be able to withstand temperatures up to nearly 212 degrees f (okay, maybe not that much, probably only about 80-90 degrees, or the temperature of hot food). It will also need to be completely food safe - not just for dry foods or short periods. And of course I'd like them to be durable. I have only been able to find one resin that matches these criteria, but it only comes in clear, and I don't know of any food safe resin dyes. There may be other materials I could cast with, but I'm currently not aware of any. Thank you for any and all suggestions.

 

[cavx]

You would be OK with polyurethane, but I would NOT use polyester resins for anything food related as it tends to leach out stuff for days and even weeks. Basically if you can smell it, it is not safe to use. Polyurethanes cost more, but cure way nicer and would be safer to use. I recent;y made some prop ice cubes. Not for placing in a drink, but for displaying a drink.

I also learned what makes certain silicone "food grade" recently. It turns out to be the max temp they can handle before burning. Food grade can be placed in an oven.

 

[penabled]

Permatex makes at least two types of high temp silicone gasket material. One goes as high as 650 degrees, not sure you would want to eat food that was cooked in/on it.

Also I think the idea with the clear food safe resin is that you use it to coat whatever you make with it to make it "food safe" not as a casting resin.

 

[samiamuc]

Thanks for the help. I'll probably just have it printed or cast in stainless steel from shape ways, and then maybe plated in silver.

 

[lmgill]

I've worked with plastics for about 35 years and I pretty sure you would not be OK with Polyurethane. It gives off solvents for a long time. There may be some specially formulated things out there, but I am unaware of them. You really need a thermo plastic, as they are chemically stable. Most plastic forks are injection molded from polystyrene so an ABS print would work. (Polystyrene & ABS are both thermo plastics)
3D printing in metal may be an option, but I believe you will get a lot of artifact surface texture.
You could also have it cast in pewter. Many period utensils were made of pewter. If you 3d printed a mold, you could pour this yourself.
Here is an example of a 14th century spoon being made in the correct period manner with a mold carved from Wonderstone (from Africa) and pewter poured into the mold.

These pieces are made by Robert MacPherson and his wife. www.billyandcharlie.com/
Pewter melts anywhere from 170–230 °C or about 330–440 °F, so if your 3d print will tolerate that temp, then you could make a number of these from a strong food safe metal,(Just buy a pewter ally without lead) relatively cheaply.

On a side note: Robert also happens to be one of the best armourers in the world, although now somewhat retired due to injury.

 

[Redd430]

I agree with Imgill on the pewter suggestion. You can get high temperature silicone fairly inexpensively, though it will be more expensive than the normal silicone meant for resins. I have worked with pewter before, and for items that are relatively smooth without a lot of fine detail, we (I was helping a person do a demonstration, keeping an eye on the temperature and pouring the demonstration pieces while he would explain the process and answer questions) cast at around 550°F. If the item has a lot of fine detail, like one time we cast a thin butterfly with lots of small holes in the wings, we would cast at 650°F.

 

[PoopaPapaPalps]

I would avoid using any poly-anything if you're gonna make something to use to eat with (that's just my opinion). If you can't make them yourself or get someone to make them for you using metal or wood, I'd go with pewter if you can and, it shouldn't be needed to say this, get lead-free pewter if you do.

 

[lmgill]

I would avoid using any poly-anything if you're gonna make something to use to eat with (that's just my opinion). If you can't make them yourself or get someone to make them for you using metal or wood, I'd go with pewter if you can and, it shouldn't be needed to say this, get lead-free pewter if you do.

"Poly-anything" is not really correct, Polystyrene is what virtually all plastic cups, forks, knives are made from. Polyethylene are what milk jugs are made off. As a thermo plastic, it is chemically stable, as they are not made by mixing two chemicals together to harden them, those are thermoset plastics. (Epoxy, polyester, polyurethane)
The easiest way to understand the difference is:
https://en.wikipedia.org/wiki/Thermoplastic

and

https://en.wikipedia.org/wiki/Thermosetting_polymer