One More Discovery

In the previous posting I reported that I had been able to sinter small amounts of copper and Bronze XT in combination with Low Shrinkage Steel XT. Pushing the limits just a little bit further, I tried to fire bigger amounts without pre-firing.

Remember the project “Overlay with Bronze XT? I re-made it with Low-Shrinkage Steel XT. Copper backing is 4 cards thick, each overlay is 4 cards thick.

It worked.

Overlay with Low-Shrinkage Steel XT

Two hours firing, no pre-firing, full sintering. Just like the old silver clay.

And it worked again.

Skyline Ring

And again.


And again.

Another Room

At one point I started to add a copper circle and a Bronze XT circle to the batches. While the copper circle sintered some of the time, the Bronze XT circle did not sinter at all. They sintered only when they were combined with Low-Shrinkage Steel XT in a single piece.

The instruction manual is about to be updated. Except for the new discoveries discussed in the last three postings, other issues will be revisited, such as pre-firing on a stove top vs. pre-firing in the kiln, arranging pieces in the firing vessel, and ramping speed.

22 Responses to “One More Discovery”

  • Kelly Says:

    This is amazing!!!!! Whst time we will save! Is that the building ring you were making In class?? It looks great!


  • Loretta Says:

    very exacting!

  • Jennifer Says:

    This might be a silly question, but can we assume that this would work with JUST the copper and/or Bronze? Provided they are smaller pieces of course.

  • Tana Says:

    So, if I had a Mokume ring with these three clays, do you think I could do it in a single stage?

  • Christy Anne Miller Says:

    Can’t wait to try this. Thank you Hadar

  • Carolyn Curran Says:

    Thanks for timely information. This novice metal clay person doing experiments with steel clay for first time. Need any input on firing I can get….

  • Sue McNenly Says:

    Hi Hadar. I don’t even use your clays (I’m primarily a silver girl), but I so appreciate all of your experimentation. It gives me hope that one day we will have 100% firing success easily with all of the clays just like with the silvers. I thank you from the bottom of my heart for your constant innovation.


  • Anita Leclercq Says:

    Is that 2 hours at high fire?

  • Marlynda Says:

    Wow and thanks again for your continued experimentation.
    See if I have this correct. This experiment worked because you are using the XT clays with quick fire copper together?? or because these 2 clays are used with the low shrinkage steelXT?? All of the experiments which worked had the low shrinkage steel XT?? Were you using the high fire schedule?

  • Hadar Jacobson Says:

    Tana, You could, but with these 3 clays the contrast is different than with the copper/bronze/steel combo at mid-fire schedule.

  • Hadar Jacobson Says:

    Jennifer, This is exactly the point. It works only in combination with low shrinkage steel XT. Doesn’t work with copper and bronze on their own.

  • Hadar Jacobson Says:

    Kelly, Yes, that’s the one!

  • Hadar Jacobson Says:

    Anita, Yes. 2 hours, hi fire.

  • Hadar Jacobson Says:

    Marlynda, I was using low shrinkage steel XT in all my experiments. In fact, this is the only steel clay I am currently using because it can do whatever the others can do. Since it requires high-fire, I combined it with copper and Bronze XT, which are also high fire. Rose bronze will work too. The only clays you can’t use in this mix are regular bronze, brilliant bronze and white bronze. Does this answer your question?

  • Hadar Jacobson Says:

    Sue, Thank you for saying this.

  • Cindy Pope Says:

    Hi Hadar,

    Thanks again. So the layered piece had copper on the back so there are parts of the copper and Bronze XT overlays that are touching mostly copper and just a bit of the steel. This is pretty interesting.

    I will be doing some experimenting for sure.

    You are the best!

  • Denise Says:

    I’ve tried firing small pieces of Low Shrinkage Steel XT with inlays of copper four times and could not get the copper to sinter in a single firing, though the steel s sintering beautifully with no cracking or warping. Are you still using the coconut carbon? I’ve also tried it with inlay of Bronze XT and the bronze wouldn’t sinter either. Any suggestions? I would so like to have a steel combo that I can fire in one stage since I’ve had such problems with the steel cracking on the first burnout stage.

  • Hadar Jacobson Says:

    Cindy, That’s correct!

  • Hadar Jacobson Says:

    Denise, Please send a photo of the piece to my email address: It’s hard to tell from the verbal description.

  • Cindy Pope Says:


    Would Denise be using a muffle kiln. Maybe reducing the ramp speed?


  • Linda Reboh Says:

    Hi Hadar,
    I’m out of my splint and been experimenting a little with combining the copper and bronze XT with the low shrinkage steel XT. Will this work if I use the steel as the base? I ask this because won’t the this steel shrink the least?
    P.S.I love the low-shrinkage steel XT the best!

  • Hadar Jacobson Says:

    Linda, Actually copper will shrink the least, but I’ve made many pieces with these three metals with :ow shrinkage steel XT as the base.

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