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When all else fails: improvise.

By now everyone working with bronze clays knows getting colorful patinas is unpredictable. What to do; What to do when you are preparing pieces to be fired and need a usable patina?

My experiments using metal clay powder haven’t done so well.  I have lots of powder but no success stories from the kiln.  Not having a programmable kiln means I have to manually try to control the temperature.  Not the most reliable method.  While I save up my courage to try the powder again, I took on a couple other projects that needed some color.  Copper and bronze are compatible. Why not use a copper wash and see what happens?

I took pieces that had been fired previously and some that were unfired.  A little copper powder and some distilled water brushed and dried onto the pieces.  The kiln is unpredictable enough.  I use coconut carbon to fire the bronze.  For backup, in case the color isn’t right, I have a small carton of coal charcoal/carbon.

As luck would have it the first two sets of earrings come out of the coconut carbon sintered and with lovely fall colors – probably from the copper. A little more work on the highlights of the flower petals for contrast and they’ll be ready.

Now for the ones that had been fired previously. They went into the coal carbon and came out with more subtle colors. The woven earrings did not have a copper wash but after being fired the first time they had been buffed to a yellow shiny bronze.  Her Shoe had been fired in coal carbon after being fired in coconut carbon.  Then it was buffed and became very black & shiny.  This time, it went into the coal carbon with a copper wash on the upper part of the shoe.  It came out with a blue cast to the black and rustic colors where the wash was applied.

Autumn Flowers

Autumn Colors

Her Shoe

Woven Bronze

Color didn’t just “return” –  it’s bigger and better!  How did it know to create contrasting colors between the flower pedals with a GREEN background?

CAB'z Photos on Flickr

This piece of bronze clay and its impressed flower design have been fired several times.  It was one of the first pieces I fired and  it went through several more attempts to get colored patina.  In between each firing it was sanded and burnished.  This time it came out of the kiln with better than expected results! It made all those other “failures” worth it.

I stared with fresh charcoal – coconut from Rio Grande – out of the same bag I used in the past. The last 2 full firings have been slightly hotter than the first. I ramped up quickly to 1200F, then took an hour  to reach 1500, allowed the temperature to go up to 1550F for a short time, and then kept it at 1500F for 2 hours.

This time I opened the top of the kiln and when the kiln reached 550F; removed the steel box.  After about 20 minutes, I poured the charcoal through a screen and could see the colors immediately.  Quenched the pieces in water.  I had read about the colors disappearing but I worried anyway!  After fishing them out of the water, the pieces went back to the screen and were set in front of a small fan.

It is the first time I have seen pinks.  In the past only one piece had a little red.  This batch had several with brilliant  red and pink.  One other observation: When I opened the lid and looked at the charcoal, two or three specks of bright blue were visible.

This is evolving into a battle of wills.  Today’s bronze came out of the kiln with a strange mix of grey and dull green colors that had unpredictable bright appearances of orange.  Better colors than the first batch, but a step down from  last week’s efforts.  The other

CAB'z Photos on Flickr

two firings had at least some noticeable change of color when the air hit them as they left the hot charcoal.  This time the pieces had little to no change in color as the air hit them.

Impressed Leaf Pendant with Pearl "Node"

That’s not to say the firing was a wasted effort.  This pendant has subtle colors that stand out because of the burnished highlights from the impressed design.  Not a perfect piece, but they are getting better.

Because of the dull grey that settled over many of the pieces, I re-heated the kiln for  several pieces hoping to liven up their colors.  They were already fired, so I let the kiln ramp up quickly to 1550F and held it for a short time; then let it cool to 800F.  Removed the steel box, poured out the charcoal.  Almost no change.  One looked more dull!  On some of the others the burnished bronze looked more red.  That’s all.

Wrong temperature or timing? Is the charcoal worn out from these half-hearted efforts?  Contaminated?  I’ll confess to testing a couple sealants on the underside before deciding to re-fire them.  No way to know so next time: fresh charcoal.

Deep Impressed Design

Leafy Earrings

Time for Plan B: Work with what you have.  Not a bad plan and not bad results.  I was happily surrpised that neither the first nor the second firing made these pairs mismatched.

The burnished shiny surface makes a nice contrast to the impressed designs filled with patina colors.

I’m addicted. I didn’t think it would happen but now it’s too late. As a polymer clay addict, I thought this was too temperamental and time consuming to become another addiction. I was wrong. Wrong twice: I never thought metal could have these colors. More photos

Today's Favorite

This time I kept the temperature closer to 1550F for two hours. I forgot to raise the container up so the air and heat can circulate but it didn’t seem to matter.

There seems to be no pattern to the resulting colors. I had some that were fired before, some that dried for over 48 hours, and some that dried for about 12 hours. Last time they were in the fridge to dry, not this time. I did notice a little warping that had to be corrected this time.

Not So Identical Twins

The 2 circles had been fired and buffed. Except I did not remove a beautiful red “splotch” on one of them. Is that the one that has so much red after being fired today? The other one has a lovely gold center and more orange outer ring. But they sure don’t look like they belong together. Next time I will refire the green ones and see if they become more colorful with greens.

I suspect there is no pattern. What if it is totally random based on temperature? The difference in matching pieces fired quite near one another might also be a result of one staying in the charcoal longer than the other. What if instead of fishing them out with a slotted spoon, the charcoal could be poured through some sort of screen?

Well, there will be a next time. Maybe the mystery will be solved then.

I bought Bronze Clay some time ago.  After reading a basket full of experiences online and conflicting instructions, I never got around to opening the packages.  This weekend I got brave and set aside plenty of time to work with it.  

My first attempt to condition the clay was a mess even though it was on a well oiled plastic (former) page cover.  I pressed on.  The glob went in the fridge to cool while the moisture content evened out.  It was time to clean up my hands! And my work area. Then I got out the other tools. (If you’d rather skip the rest you can check out the photos.)

Formed Bronze Clay

To my surprise about a half hour later, the glob came out of the fridge without an attitude.  Now I could work with it. This was not so bad after all.  The texture and consistency was pretty good. 

I decided to do a variety of shapes, all about 3mm (7 cards) thick.  The concoction in the middle is “mud” to fill any cracks before firing. Somewhere I read that using a magnifying glass would be a better way to spot those cracks that tend to show up after drying and greatly expand during firing.  I got out my magnifying glass that is used mostly for reading pottery markings.  That would come in handy later.

I added a couple bronze jump rings and a copper wire  to 3 pieces to test the results.  Who wants holes shrinking leaving no way to connect magnificent new pieces? All the pieces sat out at room temperature to dry over night. No warping was noticed. A few small cracks were filled.  Bumps were smoothed.  After checking (one more time) a series of charts and instructions for bronze clay in a Paragon Firefly kiln, I was ready to start.  I decided to go with the fast ramp up, and to try to keep the temperature at 1490 F for 2 hours.  A bit of a chore because my kiln is not programmable. But not nearly as big a chore as trying to control the ramp up time.

I thought two hours left me plenty of time to do a few other things.  Then the temperature starting going up, reaching 1550F and even a few degrees more before I convinced it to return to the 1490F range.  

Burnished and Refired with glass

My kiln is outside on an enclosed stand that has a cover.  Despite the threat of rain, probably a bad idea to lower the cover. The temperature stabilized, with the readings fluctuating between 1488F and 1508F. No more incidents. The 2 hours passed. I unplugged the kiln.  When it reached about 500F, out came the stainless steel container. Fishing around in the carbon particles with the required slotted spoon didn’t take too long to find all the pieces. But I can see why it would be important to keep in mind how many pieces you were firing.

Here are 2 of the pieces after being burnished.  They went back in the kiln to see if I can get glass frit to stick to them.  That’s a story for another day.  More photos