Saturday, 21 February 2009

Torch Firing PMC & Art Clay Silver

Torch Firing Process
(With thanks to Tim McCreight & his article in Studio PMC)
Allow the work to dry overnight or drive off moisture with a hairdryer, or in a slow oven. Make sure it's completely dry or the work can explode! Torch firing is not recommended for large items and you need good ventilation as you'll be close to the clay when the binder is burning off.
2. Place the work on a soldering block or fire brick, which is in turn set on either a fireproof surface or something you don’t mind being singed (like a piece of plywood). If you are working on the kitchen counter and the piece rolls off the block you don’t want to scar the countertop.
3. Light the torch and hold it so the flame is nearly vertical with the tip of the cone about 3/4" away from the work. Within a minute, the piece will be enveloped in a soft flame as the binder burns away. The flame will soon go out by itself. Within another minute, the piece will start to glow red. Continue heating until this becomes a bright and luminous color. At this point, glance at a clock.
4. Hold this color as uniformly as possible for about 5-7minutes. When the time is up, turn off the torch and allow the piece to cool. If you're not sure it's fully cooled use tongs or tweezers to pick it up and (providing it's not stone set) quench it in water.

A suggestion - Melt some Silverclay on Purpose
Most standard handheld torches are rated at 2000F so they can melt silver clay, in an effort to avoid this it's worth doing this experiment so you know what to look for.

Pull off a pea-sized bit of your chosen silver clay (PMC or ACS), split it in half, and roll out two small rods. Follow the instructions above with one added step. Concentrate the flame on one of the rods in an effort to melt it. You’ll see a bright mercury-like skin form on the piece and the red color will become even brighter. The edges will start to curl and the metal will be drawn up into a ball.
Make a mental note of what you saw. This way you’ll know the signs of melting, and you can withdraw the torch in time before damaging a piece you care about. To complete the experiment, allow the other rod to cool and test it by bending, filing, burnishing, and polishing. This will confirm that, sure enough, torch firing really works!


  1. I have a question sort of related to this....I have a friend who is a blacksmith. If she makes me an etched iron medallion, can I add PMC gold or silver accents to it? I was thinking about filling/tracing the etched design with silver syringe paste and firing, but I'm concerned with how well the iron and silver will bond. I wouldn't want the silver to fall off the medallion.

    I'm very new to working with pmc and have never worked with any other kind of metal before.

  2. I've never tried bonding silver to iron but there's a man called Janos Varga who does. His etsy shop is blindspotjewellry - he might be able to help.
    Alternatively allow enough gap in the design so that if it doesn't bond you could drill it through and rivet it in. (or try a small scale version)
    Nic x

  3. can silver clay that's been fired, be melted down? And if so, how so? thank you. Trish

  4. Hi Trish
    Yes PMC that has been fired can be melted down.
    If you have quite a bit then you can send it to a refiner like cookson precious metals (UK)
    or you can cut it into smaller pieces and use it as casting grain.
    You need quite a hefty torch and a crucible set up if you're going to do it yourself.
    Nic x

  5. Hi,

    I am new to this and am I little bit confused about the firing time using a firing torch. On the instruction it says fire the piece for 1- 1.5min for pieces under 5g. However you and a few other people say a longer time. How do I know when the piece has been fired enough, what are the effects if the piece has been under fired.

    Thank you

  6. Hi Sharon
    Yes I've seen perfectly strong things torch fired in 2 mins but they were fired by a Japanese master using a HUGE torch. It was a process I wouldn't like to emulate as he took them to almost melting point (on one pendant we actually lost a little of the detail as the top surface had flowed a little)
    For someone new to torch firing I'd suggest that firing the pieces a little longer will help make up for the difficulty in guessing how hot they are. If a piece is under fired then it can result in only the outside surface being fully scintered. Your work would then be brittle and liable to break.
    Are these pieces flat or domed? If they are flat pieces and no bigger than a few cms you may find hob firing is also suitable.
    Hope that helps :)
    Best Regards
    Nicola x

  7. Thank you for getting back to me. One more question !!! Can you advise the best thing to use to polish fingerprint/handprint jewellery. I was thinking about getting a tumbler but suddenly thought the sand used will ruin my hand print ? my pieces are not coming out flat so they are really hard to get an even polish with sandpaper. thank you x

  8. How are you making the prints so they don't come out flat? I use slats to get initial clay even, then the finger print is taken and the shape cut out around the print.
    This results in a nice flat pendant that you can polish up with relative ease.
    If the pieces are very bumpy then tumbling them with a polishing medium like barrel bright in steel shot will make them shiny but it wont hide any marks etc that are already there.
    I'd suggest making a tester to see how long you can tumble without changing the print.
    Mines about 1/2 hour....

    If you want to check technique then this months making jewellery has a fingerprint tutorial in it. :)
    Nicola x

  9. Thank you so much for your advise, I really appreciate it. It's really nice to know that there is someone out there to help. You are the silver jewellery Guru. I am trying to make a charm bracelet for my mum.I have managed to make the plates so I can print the hand prints on to the jewellery and have a lovely flat piece to start of with but after I have fired it, it tends to bend. (I think this means I have heated it too much?)The hand prints were not very deep so after polishing, the hand shape started disappearing. I think I have sorted this out now, I am using a deeper print. My biggest problem now is on some of the charms the hand/foot has changed colour (blacky/purple)the rest of it has remained ok it's just the print itself. I don't know why this has happened. I really wanted to get this right, as I was planning on making one for my grandma and mother in law but I just solve one problem and another one crops up. All these mistakes are getting quite expensive now. Thank you Sharon xx

  10. Hello,

    please help me: today I fired a silver clay pendant and it curled during firing process!

    Is there any possibilty to flatten it AFTER it was already fired?

    It was supposed to be a nice flat pendant so it doesn't look nice like this, with only bottom part curled...:(((

    Please help me with an advice,

    best regards,

  11. I bought some micron papers [3M I believe] from a silversmith in NE Minneapolis. Works like a charm. You would only get the hills, not the valleys with this method.

  12. Hiya, thanks so much for posting all of your advice and tutorials, they have been very helpful to me. I am having problems with torch firing as my pieces are brittle after firing and some narrow pieces (3mm tube shapes)have broken, also some clay that I had pasted together came apart after firing. All of my pieces are fairly small and thin so I was firing them for 4 mins, I have now extended my firing time to 10 mins to be sure they are fired for long enough but I'm still having the same problem. Any advice would be greatly appreciated as I don't have a kiln and cannot fix the pieces so I really need to master this torch firing business!. Many Thanks

  13. Maybe you're not firing them high enough.
    Try melting some on purpose the hotter you fire
    it the better the sintering tends to be.
    (stronger end result)
    If you overfire on purpose a few times you'll know the
    signs and can fire hotter :)
    Nic x

  14. Hiya, Thanks for your help, I've tried that but I think I'm getting a pretty high temperature as it glows at a very bright orange - I have also lost the detail on the top of a couple of pieces as the surface has melted so I don't think I can go much hotter. I have wondered whether I'm not keeping the temperature constistently hot as I fire a couple of pieces at a time, they do glow for the whole firing period though - do you recon that may be the problem? Thanks so much.

  15. Yes it's because you're firing multiple pieces, the temp needs to be pretty constant for full sintering :)

  16. When torch firing PMC3 can you fire with a gemstone set in the clay


Please leave a comment. I love reading your questions & hearing what you think! It's a great way for me to find and visit your blog too :)

You might like reading these too:

Related Posts Widget for Blogs by LinkWithin