Compatibility Chart for Firing Different Clays Together

This is long due, but I have finally been able to do what many of you have asked for: create a Compatibility Chart reflecting which metal clays can be fired in one piece, in one firing, and at what schedule. The chart also shows which metals can be fired together in more than one firing. Please download the file from the right-hand pane of the blog.

This chart goes hand in hand with the file “Firing Schedules for Hadar’s Clay™ – Quick Reference Table”. This file has just been updated and includes firing schedules for Quick-fire copper, bronze, White Bronze, steel, and Pearl Grey Steel.

The expanded instruction manuals for all of these clays have also been updated. The Instruction Manual for Hadar’s Clay™ – Quick-fire Copper and Quick-fire Bronze in particular, includes instructions on how to make the firing box, what carbon to use, how to position the pieces and the box in the kiln, etc.

I hope you find it helpful.

One important update is how to fire together copper and White Bronze, or copper, bronze, and White Bronze. This does not require a special kind of copper powder and can be done with the existing Quick-fire copper.


I am still trying to shorten this firing schedule, but what works so far is firing the mixed metal together, repeating the firing schedule for White Bronze (i.e., firing twice in succession according to that schedule), with two hours hold time in each firing instead of three.

Sometimes the copper and the White Bronze react and create a third bronze color, as you can see in the photo. This may eliminate the need to include bronze in order to achieve the three colors in one piece.

The combination of copper and White Bronze has a beautiful effect when it is applied in caning and mokume-gane techniques. These are techniques that I am exploring at present and have already presented in my workshops in Europe. They are also the topic of many workshops scheduled for this year and next.

10 Responses to “Compatibility Chart for Firing Different Clays Together”

  • lindamay Says:

    You are truly awesome Hadar. Many thanks for all the priceless information and all your hard work.

  • heidi jo Says:

    Is your clay compatible with other brands? Would the clay blends you’ve noted here work the same way with other brands? (for example – would CopperClay work with your bronze or ArtClay silver with your copper, etc). Just wondering how I can utilize supplies I have of different brands – and how to incorporate some of the new products you have that look SO wonderful! (Can’t wait to try steel!!)

    Heidi Jo

  • Chris Pate Says:

    Hi Hadar, glad you are back from your hectic teaching schedule. I have tried to email you but it keeps bouncing back. Just to say thank you for an amazing and inspiring course in York. The journey back to Bristol was so much quicker as my head was full of ideas!!
    Thanks again.

  • Deanna Duncan Allen Says:

    Thanks so much for these compatibility charts. They really are a great reference as I refer back to the notes from your Colorado class.
    I really appreciate your hard work and dedication!

  • Hadar Jacobson Says:


    I honestly don’t know. Haven’t tried it yet. If you try, I’d love to know your results. Thanks!

  • jenny james Says:

    I fired white bronze with copper today. Used WB as the main piece and had a small viney pattern with sparse small leaves filled with copper. In other words the copper content was pretty small. I fired twice in succession with the WB schedule provided. On the first firing the piece looked fine but after the second firing there was a large crack in an area where the copper apparently didn’t allow the WB to shrink as much as it was trying to. Have you seen this before? Did I do something wrong?

  • Hadar Jacobson Says:


    It doesn’t seem to be a shrinkage issue since white bronze and copper shrink about the same. Did the copper disappear after the second firing? If it did, it had probably oxidized, maybe because it didn’t have enough carbon on top of it. With such a log firing the piece needs a lot of carbon. White bronze will also crack because of fast ramp? Did you slow-ramp the second time as well?

  • Steve Says:

    Cindy Silas has printed some instructions on mokume-gane with CopprClay and BronzClay and paper clay. See at
    It looked very nice but my try was a disaster (however I do not think I used the correct firing temperatures).
    You might want to see what she did since you are experimenting with mokume-gane, too.
    Thanks for all the great information,

  • Hadar Jacobson Says:


    This is one well known way of doing mokume gane with polymer clay. This is not how I do it though. I was looking for a photo of a finished product done this way and couldn’t find any. Could you direct me to a link? Thanks,


  • Steve Says:

    The one noted above should work:
    It has one finished picture on the page. I clicked on the above link and it worked for me.

    My trial didn’t sinter, but I believe I used too much paper clay and fired using your directions with a different type of metal clay (I had some open BronzClay). That might have been my problem.


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