Update to Firing Schedule of White Bronze

After firing White Bronze almost every day since it launched, I have arrived at a new schedule that works for both thin and thick pieces. It involved a little surprise, but I’ll save that for later.

Here is the new schedule:

Ramp at full speed to: 500°F/260°C; No hold.
Ramp at 400°F/222°C to:
      1160°F/626°C (top loader kiln);
      1250°F/676°C (front loader kiln)
Hold for 3:00 hours

If you don’t want to deal with 2 ramps, use the following, simplified but longer schedule:

Ramp at 400°F/222°C per hour to:
      1160°F/626°C (top loader kiln)
      1250°F/676°C (front loader kiln)
Hold for 3:00 hours

Total firing time is 4:00 to 4:30 hours.

You will find programming instructions on page 4 of the White Bronze instruction manual. All of the manuals – for Quick-fire clays, for White Bronze alone, and the Quick reference guide – have been updated as of 5/4/2010. Please download the new versions.

The manual for steel clay will be updated with the upcoming launch of Pearl Grey Steel.

Now to the surprise. I had a little piece of Quick-fire bronze that needed re-firing. Having nothing to lose, I decided to add it to a batch of white bronze. The repair worked! I then fired pieces of bronze with White Bronze, using the above schedule for White Bronze, and all the bronze pieces fully sintered, although the firing temperature was lower by 300 degrees than what is required for bronze. It seems that at least in this case, slow ramping and longer hold time compensated for the lower temperature.

Furthermore, I included in this batch a mixed piece of bronze and White Bronze. Here it is, as it came out of the kiln:

t-From the kiln

And here it is after sanding and buffing:
t-After sanding

Why is this good news? First, if you have just a few pieces of bronze and White Bronze, there is no need for separate firings.

Second, contrary to what I thought before, in order to combine bronze with White Bronze, it is not necessary to fire the bronze first; they can be fired together following the White Bronze schedule.

So, if you want to mix copper, bronze, and White Bronze in the same piece, you have two options:

1. Fire the copper first, then add bronze and White Bronze and fire again;
2. Fire the copper and bronze first, then add White Bronze and fire again.

I am currently testing combinations of copper and steel. Copper and steel, too, can be fired in the same batch with the same firing schedule. There is no need for separate firings.

Pearl Grey Steel and copper can be combined in the same piece, and the results are amazing!


15 Responses to “Update to Firing Schedule of White Bronze”

  • Candi Says:

    Wow this is all so exciting! Can’t wait to try it!
    Will be using White Bronze for my charms for Charms for Chairity!
    Thanks so muc1h Hadar

  • Celina Says:

    Hadar, you are soooo generous and wonderful, I’m just enjoying your beautiful, beautiful pieces! Thank you.

  • Stacy Smith Says:

    This is exciting news! My attempts with the original schedule didn’t go very well. Of course, it would help if I had a programmable kiln… At any rate, I’m motivated to try again this weekend. Thanks!

  • Bobbie Rucker Says:

    This is great, I esprcially loved the piece before it was buffed, so beautiful.
    Thanks so much.

  • Jenny James Says:

    OK- am I the only one who didn’t know that a new clay “Pearl Grey Steel” is in the works? Did I miss an earlier article or discussion or something? Are there pix somewhere- are we going to or have we already found out what it is, how it looks… etc?

  • Hadar Jacobson Says:

    Jenny,

    It’s not out yet. You haven’t missed anything. I will post photos soon.

  • Ruth Baillie Says:

    I tried firing white bronze with your quick fire bronze using the above schedule as you outlined but the quick fire bronze was very fragile and crumbly after firing while the white bronze did fine.

  • Virginia Vivier Says:

    Hadar,

    I am having problems using cork clay to make hollow bronze clay beads. Cork clay won’t burn out completely and most of the bronze clay broke apart during firing. I live in Tucson, AZ where the air is very dry. All the pieces were thoroughly dry prior to firing.

    I also tried burning out the cork clay at 500 degrees for 15 minutes before firing, but still wound up with cork clay pieces rattling around inside the beads.

    What is your firing schedule for 1″ bronze clay spheres with cork clay base? Do I need to drill a hole in each piece? I have your book but didn’t get a clear idea as how to solve this problem.

    Thanks so much!

    Virginia

  • Hadar Jacobson Says:

    Virginia,

    Instead of 500 degrees fire at 1100 degrees for one hour before proceeding. Cork clay does not burn at 500 when it’s burried in carbon. Also, make sure there’s not too many pieces with cork clayin the same batch. Let me know how it goes.

    Hadar

  • Virginia Vivier Says:

    Opps, I forgot to mention that when I attempted to burn out the cork clay inside 1 inch spheres that I put them on an open ceramic kiln shelf rather than inserting them into carbon in a stainless steel container.

    I planned to refire them with bits carbon inside each piece once the paper clay was burned out.

    should I try to burn out the cork clay on open kiln shelf at 1100 degrees?

    And yes, I probably did have too many pieces in the firing.

    You’re the best!

    Thanks so much for the help.

  • Hadar Says:

    Virginia,

    It’s not a good idea to fire bronze in the air. I suggest 1 hour in carbon at 1100F before continuing to the sintering temperature.

  • Vanessa Weber Says:

    Should I assume that the original copper and bronze won’t work with this – only the quick fire variety?

  • Hadar Jacobson Says:

    Vanessa,

    Yes. White Bronze is also quick fire and shrinks less than the original clay.

  • Ginny Says:

    Just started working w/wht.bronze and pieces are a grey/brown color after firing and brushing. How can I achieve the wht. shiny finish as seen in your photos?

  • Hadar Jacobson Says:

    Ginny, After firing the pieces have to go through a whole finishing process. It is described in my book “The handbook of Metal Clay: Textures and Forms” and also in “Mixed Metal Jewelry from metal Clay”.

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