1. I’ve been asked how White Bronze reacts to patina. You can see the result in the photo below.

2. How well does it pick up textures? I tried to make my Collage of Textures pendant (first project in the my first book) with White Bronze. It reacts well with liver of sulfur and seems to pick up textures very well.

Before Firing

After Firing

3. Smooth/matte/satin finish. Achieving these finishes was no harder than with silver, copper or bronze clay.

4. Combining copper with White Bronze.

5. Reaction with bronze. I fired both bronze and White Bronze on a copper piece, without sealing the bronze as I would have done with silver. Both sintered, and there was no alloying or change in color.

The following bead has been waiting for this moment for about two years. I fired the copper and the bronze with the intention of adding silver to the bottom part. It was just then that I found out about the reaction of silver and bronze (you can read all about it in my second book), so I stopped working on the bead.

6. Sticking to copper and bronze. Since the firing temperature of copper and bronze is higher than that of White Bronze, copper and bronze need to be fired first. I placed an unfired piece of White Bronze on a fired piece of copper and a fired piece of bronze, and re-fired.

The results were inconsistent. I repeated it a few times and sometimes they stuck, sometimes they didn’t, regardless of whether it was copper or bronze. My guess is that they will stick if there is a way of creating some pressure between them. The following test supports this hunch. It seems that the pressure of the carbon on the piece was not enough.

7. Inlay.

White Bronze in copper

White Bronze in bronze

The following photo shows side by side inlay of White Bronze in copper (R) and inlay of copper in bronze (L).

Color comparison

As you can see, the contrast between bronze and White Bronze doesn’t seem very sharp. Over time it may improve when the bronze yellows some more. White Bronze has not changed in color so far.

The inlay pieces above were only partially successful. In the center of the pieces the metals bonded well with each other. On the peripheries some of the inlay chipped off and required repair and re-firing. It seems that on the peripheries the pressure is lower than in the center.

In the following piece I avoided inlaying the White Bronze on the borders of the piece. The bonding was fine.

The pieces in the photos above (click to enlarge) are not made out of silver or steel. They are made out of a new copper alloy that I call “White Bronze.” This new form of Hadar’s Clay will soon be available for sale on my Web store.

Here is how the pieces looked before firing:

I have prepared samples of Quick-fire Copper, Quick-fire Bronze, and White Bronze, textured and non-textured.

The following photo is taken next to a silver piece that may be familiar to you as a project from my first book.

Here are some process photos:

Textured and folded

Dried

Fired

Next, some pieces in copper and bronze. Unlike the copper and bronze pieces, the White Bronze piece was textured before folding. When White Bronze is not textured, it comes out as smooth as copper and bronze.

White Bronze is compatible with both copper and bronze; there is no undesirable reaction between them as there is between silver and bronze.

The firing temperature of White Bronze clay is a lot lower than that of bronze clay, though. So in order to make combination pieces of either copper and White Bronze or bronze and white bronze, the copper and bronze parts have to be fired first.

White Bronze was wrapped around fired copper, then fired.

The result is the piece on the left. On the right you can see the same piece with silver substituted for the White Bronze.

There are still some tests that need to be done. For example, I need to determine the extent to which White Bronze clay sticks to copper and bronze. I will post my results soon.

As you can see from the photos, the shrinkage rate is similar to that of Quick-fire Copper and Bronze. The firing time is about the same and the temperature is lower. The fired pieces are as strong as those of copper and bronze.

Important Note: This is not “nickel silver” (also known as “white copper,” “German silver,” or “alpaca”). This alloy contains no nickel.

White Bronze clay will be available on my store as soon as I complete my testing and write an instruction manual. I hope you like this low-cost addition to the palette of metal clays.

1. Over-sanding prior to firing (this could cause particles from each metal to “bleed” into the other);
2. Oxidation of the copper in the process of firing.

I knew it wasn’t the first reason. Something was causing oxidation. After ruling out other possibilities, I replaced my coal carbon with coconut-shell. The differences were striking. Here is how the pieces looked straight from the kiln. I used my new firing method, 1:00 hour at 1450ºF in a fiber blanket box.

Another great advantage to coconut-shell carbon is that although I used very little carbon, very little ash was created. I was easily able to vacuum the ash and re-use the same carbon over and over.

The carbon is coconut-shell, acid washed, size 12 x 40.

Bear in mind that probably not all coconut-shell carbons are the same. Different vendors may be supplying different brands. Moreover, vendors change their own suppliers and you may be getting a different brand even if you ordered from your regular vendor. It has happened to me more than once that I was working with one supplier, being quite happy with the carbon, and then the next shipment wouldn’t work anymore.

So I suggest ordering small amounts and testing them. I can’t afford to buy from every possible supplier and test, but I would be happy to test for you if you send me samples.

If you are firing just copper without carbon (”open shelf”), it is not only a good idea but the only option. If you fire copper from cold without carbon, the oxidation layer will be very hard to remove. Moreover, internal oxidation may occur, which eventually may cause the copper to disintegrate.

(A little side note: it is not a good idea to fire copper without carbon, in a kiln or with a torch, more than once or twice. Eventually it will weaken and disintegrate. This happens not only to copper clay but also to pre-made copper sheet and tubing.)

However, if you are firing in carbon, whether copper or bronze, it is better to start in a cold kiln. The binder must burn off before the carbon is set on fire and starts consuming the oxygen in the kiln chamber. If you load the kiln at a temperature between 500°F – 1000°F, the binder has a very slight chance of burning, since it needs oxygen to burn. This will result in poor sintering or none at all. I learned this the hard way.

Is is a better idea to take pieces out of a hot kiln or let them cool down first?

Again, in a classroom situation there is sometimes no choice. But then cool the pieces immediately in water (unless they include stones). Otherwise, the exposure to heat and air will cause oxidation. The time spent on removing the fire scale may be better spent on waiting for the kiln to cool down to about 300°F.

Whether you fire small pieces for one hour in a fiber blanket box, or bigger pieces with more carbon for 2 hours, no oxidation will occur if you just let the pieces cool down before retrieving them from the kiln.

One way to avoid this is to take the pieces out of the kiln when they are hot and cool them in water. By “hot” I mean that you can absolutely wait for the kiln to cool down to about 900°F before you do that.

But if fire scale does occur, there are a few easy ways to remove it. Personally I don’t like to use pickle, but if you want to, a very mild and effective one is citric acid. (Citric acid is actually used to make pickles and exists in many food products and almost every soft drink, as well as naturally in the juice of citrus fruits.) You can get it at Mediterranean food stores. It’s also available at wine-making and beer-making supply stores, as well as at some supermarkets. It’s very inexpensive.

Here are two alternative methods that I prefer:

1. If a piece is small enough, you can heat it with a torch to red hot and immediately quench in water. The fire scale will disappear.

If you choose to do this, there are two things to keep in mind:

a. It is not recommended to do this with pieces that were fired by the “hot firing” method (in the air). It is also not recommended to repeat it more than twice or so since the copper is weakened by air firing and will eventually disintegrate.

b. After dipping in water, the piece must be completely dried on a warmer before you handle it any further. If you try to buff or sand a wet piece, you will not see metallic color and you may think that it is not properly sintered. It is not enough to dry it with a paper towel; the metal is porous and holds a lot of liquid inside, even if it looks dry on the outside.

2. Put the pieces back in the carbon. Heat the kiln to 1000°F and hold for 15-30 minutes. You can take them out hot or cold. The fire scale will be gone. This time there will be very little ash and there is no need to discard the carbon.

This piece was taken out of the carbon hot after re-firing for 15 minutes at 1000°F and cooled in water. The fire scale disappeared completely from the copper part.

I used a coarse mini-fiber wheel to clean up the steel part. It was quite easy.

With the spinner bead, I waited for the carbon to cool down and did not cool the piece in water.

Again, the fire scale was gone.

1. Torch-firing (for small pieces only);

2. Hot firing – putting the piece in a hot kiln, removing it while hot, and quenching in water;

3. In a fiber blanket box, with a little carbon, for two hours.

The third option is the same as the method mentioned in the Quick-fire bronze schedule, except that it requires two hours instead of just one.

Actually, there is an another possibility, which does not require handling a hot kiln or waiting 2 hours. If you fire copper alone, you can compensate for time with temperature. (This is true for copper, but not for bronze!) I fired copper following the firing schedule for Quick-fire steel clay. I went up to 1800°F/982°C in my top loader kiln (1880°F/1026°C in a front loader kiln), and held for 1:00 hour.

Here are the photos of before and after:

Out of the kiln

Finished

You can find the instructions for making a spinner bead like this in my book: Silver and Bronze Clay: Movement and Mechanisms, pp. 88-94. In this case, the bead and the spinner are fired at the same time.

Out of the kiln

Finished

As you can see from the second example, unlike copper and silver, copper and steel will not alloy and melt as a result of spending a long time in contact under high temperature.

Without steel present in the box, it does not seem necessary to fire at such a high temperature. So my fourth suggestion is:

4. Place in a fiber blanket box with a little carbon on the bottom and on top, with no lid.

Fire at 1690°F/920°C in a top loader; 1770°F/965°C in a front loader.
Hold for 1:00 hour.

Of course, the larger the pieces, the more carbon and time are required.

Otteline Tuitel
Non!Soesa Creatief
Hoogstraat 36A
5271 KJ Sint-Michielsgestel
(South part of The Netherlands, nearby ’s-Hertogenbosch)

website: www.nonsoesa.nl/hadar_jacobson.htm
email: info@nonsoesa.nl
Phone: +31735516676

I tested this firing method with steel clay (not stainless). I fired in a fiber blanket box at 1800°F/982°C in my top loader kiln (1880°F/1026°C in a front loader kiln). The total firing time was 2 hours.

Pieces shrank some more (about 20%) and were easier to clean up. The surface was textured with a subtle texture of fine sandpaper. With some buffing with a coarse mini-fiber wheel they became shiny. I liked them as they were, so I did not follow up with sanding. That was the easiest finishing job I ever did.

So, I may bring some steel clay to my next travel-teaching workshops. It seems that we may have time to play with it.

When handling the fiber blanket it is recommended to wear a protective mask and gloves. An alternative to the fiber blanket will be discussed below.

Cut a square out of the fiber blanket, 2 inches longer than your kiln shelf on every side.

Cut off a 2″ square at each of the four corners of the blanket.

Fold the flaps upward and pinch the sides together.

At first the walls may not stay upright. When placing the box in the kiln, support each side with a post. With every firing the box will become more and more stable, and eventually you won’t need the posts.

Alternatively, as Mary Ellin D’Agostino suggested, you can stitch the sides with high-temp wire.

It is important that the walls of the box are a little away from the walls of the kiln chamber.

This box leaves the kiln perfectly clean. It can be used many times. I haven’t replaced mine yet.

In the past I have tried ceramic boxes. I used bisques and they broke after one firing. However, this ceramic box will not break.

All it is is a ceramic kiln shelf with posts arranged around it. The carbon stays contained in the box and does not spread in the kiln. You can add more posts to build a deeper box.