Tips and Information about making jewelry

With this blog, I hope to share my knowledge, successes, trials and errors, student's work, tips, and information about making jewelry.

Wednesday, March 14, 2012

Combining Sterling Silver Metal Clay with Fine Silver Metal Clay

Hi everyone. I am working on a project that involves making a ring out of two clay types, sterling silver and fine silver. I wanted to know how to combine them without having the problems of uneven shrinkage. Additionally, I wanted to fire them together.

Here is what I made. The shank is made of sterling silver metal clay (PMC Sterling Silver). I hand carved the feather design into it. The top is made from PMC3 metal clay.

To solve the problem of shrinkage I fired them both separately.  The top (PMC3) was  fired at 1110 F for 1 hour. I fired it at a lower temperature to protect the Garnets.
The ring shank is made from PMC Sterling Silver metal clay. I fired it using the two stage system recommended by Mitsubishi.

I used PMC3 syringe and oil slip to hold them together.  I had several questions about this configuarion.

  • Do I fire it using the two stage system or do I fire it using the PMC3 system. 
  • If I fired it using the PMC3 system, would it be a good join?
  • Will the sterling oxidize and not stick to the newly added clay holding them together. 
  • Or, if I fire using the two stage system, I must lower the temperature to 1110 F so as not to harm the stones.
Well my lazy side won out. I fired it on a kiln shelf at 1110 F with no carbon for 2 hours giving the new clay time to connect to the fired clay.



  1. I guess I'm not getting why you didn't think this would work- sterling clay fires at a lower temp- all studies show that full sintering is best at the highest possible temp for the longest period of time. Yes, it should hold, but it is really strong? 1100 for fine silver seems just way too low a temp.
    I never use the 1000 for 30 min, just do a simple torch burn off of the binder- so only one firing. I really am wondering why open firing didn't cause more of a problem since the directions are pretty clear that sterling clay needs a non oxygen environment- very curious. Would love to hear your thoughts on that

  2. i love the sterling clay! thank you so much for posting this about joining pmc and sterling fired pieces--i was wondering about this but didn't have any clay left to do any tests. i love your hollow form and channel set rings--wow!

  3. Ppennee--I think she fired the shank the regular way it needed to be (in the carbon) and then connected it at the 1100 for 2 hours while it was in its sterling metal form.

    I agree with Kim as well, thank you so much for all of these tests you have been running. Whenever I get a kiln that works (I've purchased TWO separate NEW ones and both haven't worked...the second needs a replacement part already but I don't feel confident to take it apart myself and my husband is sick this week, so I still don't have a working kiln...but when I do, I'm using the Sterling clay I have stashed and ready to go in my work area!).

  4. Also, Ppennee, when you torch fire to burn off the binder of the sterling, do you leave the torch flame on the sterling until it isn't on fire anymore or do you just put the torch on the clay and essentially light it on fire and then just wait until it burns all the way through? I saw in the CoolTools blog that she also torch fires the binder off but I wasn't really understanding how she did it.

  5. Hi All, Thank for the comments. This is what irons out ideas!

    Mitsubishi requires the sterling silver to be fired in two stages the first on an open shelf at 1000 degrees F. and then in carbon at 1500 degrees F. Both fire for 30 minutes.

    Longer time is not required for it to reach full strength as their fine silver clays. So I fired the sterling silver using the recommended above schedule.

    I fired the PMC3 fine silver clay bezel at the lower temperature per the test results from the PMC Guild's specs on firing stones in place. Specifically the Rhodolite Garnets. From their report it says this stone can withstand fast firing up to 1110 F. This is why I only fired the bezel up to that temperature. I held it at that temperature for a long soaking time (1 hour) in effort to help all the metal bond better.

    Yes higher temperatures = stronger metal (for metal clay) but the stones may not have lasted. I didn't want to risk the stone. Additionally, the bezel doesn't need that extra strength like a ring would. Its not going to take the abuse like the ring shank. I choose to make the ring shank in sterling because it is so much stronger.

    My question for this experiment was when I put the two different metals together, what would be the best way to fire them? Since both metals require different firing steps. I wanted to be able to fire them together in the quickest way, so I fired the PMC3 using PMC3 new clay to connect them. Now this new clay must be sentered. Yes their is no reason why it wouldn't work on a open shelf at 1110 F. But the question was would the sterling oxidize and keep it from sentering to the PMC3.

    The answer to that question was it sentered to the the PMC3 just fine. I have tested the connection and it has held very well.

    In my next testing for the PMC Connection blog I will be testing the other ideas of sentering the sterling silver clay to see how they actually do work.
    Questions I will be asking is:

    Can I use a torch to senter PMC sterling silver and then put it into carbon?
    If so, for how long; 3 minutes, 5 minutes, or until it stops smoking?

    Again, thanks for the comments! It really helps everyone!

    1. Awesome! I look forward to that blog post!!

    2. Janet, I use a torch, and only use a kiln for casting. I was wondering if you had ever tried to connect pmc3 to .925 silver wire. I read in Lapidary Journal that the use argentium, but I don't like working in that medium. I like .925 or .999. If I use .925 or .999 sheet is it possible to use pmc3 to add depth and design? Would I use paste, connect it and fire it with a torch?
      Thank you

    3. Anastasia, yes you can attach fine silver to pmc3. It needs to be done after sintering, due to shrinkage pulling away from the un-shrinking metal. With that being said, I have also had success attaching wire to un-sintered metal clay, but the shrinkage can cause the metal clay to warp out of shape due to the un-shrinking wire.

    4. Also I just remembered that I have used a process of annealing and quenching a minimum of 6x working with .925 in order for 24k foils to attach. It brings the pure silver to the surface and also burns off impurities. This may help with the joining. I have not tried it yet on pmc and .925, but it may be quite feasible.

  6. So I see I missed that critical steps were separate- thanks for clarifying. When I do the torch burn off- all I do is light it and make sure it's burning, not just a flicker, the larger/thicker the piece, the longer the flame will last, but that's all I do. Just wait until the flame goes out, then fire at 1500 for an hour. I have done 1 hour and 2 hours both for sterling ring bands- I still like the longer time- but then I haven't wear tested both to see if there's any difference so I may just stick with the 1 hour. I have tried a similar experiment using pmc3 paste and lavender oil paste but not with a ring ( the oil paste is more difficult to get to sinter so I'm thinking major repairs on sterling aren't going to be easy). Since I set a lot of stones, this is really great to know that it will hold on a ring. If it holds up to ring wear, it'll hold up to anything!!!

  7. PPennee,
    Thanks for the information on how you burn off the sterling silver. It gives me a starting point. My next testing will be posted on the PMC Connection's blog. They and Mitsubishi have given me some clay to experiment with. The first thing I am going to try are different ways of completing the first phase. I think I might try Hadar's technique too.
    Thank again for your input!


  8. Sounds like when you fired, the pmc3 it kept the sterling from oxidizing where it joined the fired pmc3. Sterling part would have to be exposed to oxygen to oxidize. Hmmm....I've also tried this, firing both separately, but then used pmc3 to join and fired in carbon at the pmc3 temp. Worked well for me that way as well.

  9. Gayle, yes it did cover the sterling keeping it from oxidizing under the pmc3 allowing it all to sinter.

  10. hi i fired a bezel with a stone now i want ad it to a ring band how do i attch it to it also how to make a ring a size 7 let me know thanks