How to Cast and Polish a Pewter Signet Ring

Hopefully this will help a few different groups of people: those of you who want to make a cool ring (and I mean that literally when you put it on in the winter), those of you trying to cast small objects in pewter and don't necessarily need an electric melting pot, and those of you who, like me, just like reading about this stuff. If I missed people feel free to correct me :)

Anywho, let's get started!

First of all, you will need:

- Safety glasses!
- A mold of whatever you're trying to cast. I prefer to use a high temp silicone rubber but you can use pretty much anything that will withstand about 600°F. A good starter project could be a design carved into a cured piece of plaster.
- Some pewter
- A blowtorch or some other method of melting the pewter
- A crucible to melt the pewter in (a steel can will work just fine on a single use basis)
- A hacksaw
- Sandpaper and/or files
- Buffing wheels and compound
- A fair amount of elbow grease, but it's not too much, and it's definitely worth it.

DISCLAIMER & WARNING: Any techniques used here are my own, and they work for me. Use at your own risk. Also, please note that this 'ible details the use of an open flame and very hot molten metal. Please ensure that no pets or small children are around to distract you or get themselves hurt. Nothing is more important than safety, so always work in a well ventilated area (outside is preferable) and it's best to have a friend close by with a fire extinguisher or bucket of water in case something goes really wrong. After the metal has solidified, it is STILL HOT. Use a pair of pliers to handle it or just wait for it to cool down before handling. Same goes for the crucible. If you choose to follow these instructions, have fun, but be safe. :)

Step 1: Prepping the Mold

This is a fairly simple step, but the main point I need to get across here is that you want to make sure you have some kind of lubricant in your mold. In this case I'm using graphite powder (take a pencil and use a knife to scrape the lead so that you end up with a small pile of fine black powder), and I don't really have suggestions for anything else that'd work, so I'd say go with graphite powder (it's easy enough to make, anyway). If you skip this step, you may end up with castings that look like they've come from a golf ball factory.

Basically, take a brush and make sure all surfaces that the metal will touch are coated in powder. That's it! Now reassemble the mold halves and put a rubber band or two around 'em to make sure they don't fall apart when casting.

Now for the fun part!

Comments

[mr.mountaineer]

cool! i kind of like the golf ball one.

[gg1220]

Haha me too.

[Jeffrey Castro]

Hello, I have a couple ov question; however, please contact me on my e-mail. Reason being is because they involve pictures for a future project ov mine....and i would love your help in this project since i am considered a "newbie".

E-mail: [e-mail]

Please respond quickly!!

Sincerely, Jeff

[BirdManJr]

Nice job, do you sell these, if so, how much per ring, I am interested in purchasing one!

[gg1220]

PM sent :)

[mxordeath]

im interested in doing on of these, but i would like to know how you made the original mold, did you need another ring or did you have another method?

[gg1220]

Yup, I sculpted (if you can call it that) the original ring out of polymer clay, made a mold of it, and then cast it in pewter.

[Asmodeous]

Wow, thats nice. Can I just buy one off you in a size 12?

[gg1220]

Thanks!
If you're serious, I can probably do that for you :)

[Asmodeous]

Absolutely - My email address is [e-mail] We can communicate thru there.

Thanks,
Todd

[ElectricUmbrella]

Looks beautiful! One question: since it is a signet ring, how would you engrave the symbol into it? Would you need a jeweler's tool or a specific technique for it?

[gg1220]

If you take it to your local jeweler they'll probably be able to engrave it for you (they have special tools called gravers that're like carving chisels for metal), or if you have a steady hand you can go the DIY way and take a Dremel to it :)

I've personally never gotten good results with a Dremel, but I'm not at all artistic, so you'll probably have better luck than me. 
I also tried making my own graver a while back (had some tool steel blanks that I profiled and sharpened on a grinder and hammered into a wooden handle), and that worked alright. Again, having the hand-eye coordination of an artist would really be helpful if you choose to go that route.

One more thing you could do is put the symbol in it from the start. If it's a fairly simple design, you can make your clay model with the symbol you want, just make sure that all sunken areas are at least 1/16" or so deep, as you'll lose some of that depth later when you're sanding and finishing. Then your casting will be an exact replica of the original :)
I chose not to do that because the design I'm trying to (eventually) make is too complex to work that way, and since I'm making several variations upon the design I'm too lazy to make multiple molds ;)

Hope this helps!

[ElectricUmbrella]

And one more thing: I'm thinking in terms of a ring that could press a design into a wax seal - would dremels or gravers provide sufficient depth for that? It seems like casting it into the mold would be better for this purpose.
Thanks again :)

[gg1220]

I really would recommend casting it with the symbol, since you can easily control the depth of the relief when making your clay model. Dremels might be able to do that if you have a really steady hand, and gravers are generally only really useful for small, intricate designs. So yup, you're exactly right! :)

[ElectricUmbrella]

Just to make sure I'm understanding correctly, you said (in regards to putting the symbol in from the start) that I could make a clay model of the symbol, then put it in the mold and cast the ring that way? Good idea, and what you said definitely helps. Thanks!

[gg1220]

Sure that would be one way to do it, but not necessarily for casting metal, since the clay probably can't withstand the higher temperatures (but you never know, it might. Feel free to experiment!). If you decide to try this out, make sure you coat it in varnish or lacquer or something similar and use mold release (any type of oil or grease) on the clay piece so that it doesn't stick to whatever you're casting (and the rhyming wasn't intentional :P).

If you only want one symbol on your ring, try molding it into the original clay model. When you make the silicone mold of that model, it will capture all of the detail on the clay, including your design. That way, all the details are already in the mold and you don't have to worry about a little clay piece sliding around in there. And it's safe for metal casting.

Sorry for the confusion, I'm not very good at explaining things.

[ElectricUmbrella]

You explain just fine, and thank you for responding so quickly.
And just out of curiosity (last question, I promise), where did you find the ring to make the mold (or was it a clay model that you made the mold from)? Again, thanks for all the help.

[gg1220]

Haha sure, I'm always on the computer xD

I actually made the original ring, because I couldn't find a commercial alternative that fit the requirements that I had. To make that, I found a piece of 3/4" rod and molded the clay around it. Then I baked it in the oven as per the directions, and while it was still kinda soft (it doesn't harden completely until it cools down), I cut a slit at the bottom and gently pried it off. Then I glued it back together, put a sprue on it, and poured the mold! :)
It's really as easy as that.
Good luck, and feel free to ask as many questions as you want!

[pheenix42]

Where does one obtain pewter? I love this instructable, but buying metals for casting purposes is a bit expensive!

[gg1220]

Oh boy, I know where you're coming from. Well, if you want, you can start with "cold cast" metals and such, so that you have a wider range of things you can make immediately (brass, bronze, copper, nickel silver), and with less expense per casting. You should get the look and feel of real metal with this method (I've never tried it myself, but I saw a few examples at a craft fair and they looked pretty convincing).

Now for the real stuff. I got a couple pounds of pewter from Rotometals a while back, and I just recently bought 6 pounds off of ebay. If you search for "pewter ingot" and look around, you can often find some pretty good deals there. The only thing to be careful of is that you should make absolutely sure that what you bought is lead free. These people look pretty nice, if you're wondering where to go for that.

[MissouriVillian]

  A bit more price than pencils but it'll save you some effort, a little does go a long way after all.   http://www.amazon.com/Panef-Corp-Powdered-Graphite-Lubricant/dp/B0016GZQ60A

[gg1220]

Good point! I guess I'm just cheap ;)

[MissouriVillian]

Who isn't these days. It's just a question of what we're cheap on buying right.

[gg1220]

Sure is :)

[rachel]

I have been experimenting with casting pewter into a silicone mold and all my tests have come out more or less like your "golf ball" picture. I did not know to use powdered graphite, I will definitely try that to see if it helps.

Do you know why the pitted, cratered effect happens? I thought initially it was some mold release (from the original clay) left over in the mold, but since I made several castings, and washed it out thoroughly in between, I'm less convinced of that.

[gg1220]

Hope it works!

I don't know the scientific reason why it happens, it might have something to do with surface tension or outgassing from the mold (like you were guessing before), I just know that graphite works to smooth out the casting :)
I could probably ask one of my chem teachers if you really wanna know.

[susanrm]

Cool. This reminds me of the centrifugal casting class I took at MIT during IAP, in which I made the most beautiful little bronze and silver items. That was more elaborate and required more intense equipment, but the principles were the same.

[gg1220]

First of all, congrats on getting into MIT! My brother's working on his college apps now and is anxious to hear back from them whenever results come out.
For your class, did you carve items out of wax, invest them, cast, and break the molds? I would love to see some pictures if you happen to have them handy :)
Also, have you seen instructions on how to steam cast? Do you think results would be similar between the two different methods?

[susanrm]

Thanks, but I "got into" MIT through a job application. :-) I worked there for about 10 years before I got into teaching. It was overall a great experience. IAP was so cool.

Ha - you linked to Don Norris! We used to be buds when I was active as a professional jewelry maker. I'm not sure about steam casting, but I think most professionals now use injection casting. With centrifugal casting, you got some bubbles, whereas you don't with injection casting.

I don't have photos of my things... I made a mini Parthenon and a fleur-de-lis out of bronze, a silver bell (still so beautiful), and a little silver chalice with gemstones on it that was a special gift for a friend. The chalice and bell were cast from molds made from wax I shaped on the lathe of my boyfriend at the time.

And yes, that is the process we followed.

[gg1220]

Wow, all of those sound beautiful! Your friend must've been so honored to receive the chalice.

And I guess it really is a small world! Thanks for all your time, and sorry if I've been bothering you with too many questions :)

[susanrm]

Thank you. And no worries about the questions. I wouldn't answer them if they bothered me. This is a learning community, so questions and sharing ideas are great! Excellent project, by the way.

[gg1220]

Thank you! I just hope it helps out people who've been having the same questions I had when I first started :)