Aug 29 2009

The Story of Gourdelia

Gourdelia is a large copper/bronze hollow form that is a collaboration between Toni Ellis (who has been my student for nine years) and me. Gourdelia came into the world as a miniature gourd that I picked up a few years back. By miniature I mean 4″ tall and 2″ in diameter at its widest point. I couldn’t afford to use it as a mold for a hollow form in silver clay, and my base metal clay firings were rarely successful, so the infant Gourdelia slept quietly in my “Box of Odd Shapes,” awaiting her debut.

When there were no more excuses, I realized that Gourdelia’s moment had arrived. I covered the gourd with a layer of bronze clay, in a way similar to the one introduced in the “Rocks” project from my first book. I dried it, then made one vertical cut along the gourd. The clay was pretty flexible after it had dried, so it easily peeled off the gourd without breaking.

I re-joined the cut and covered the clay gourd with layers of copper and bronze clay, to create the look of inlay, or married metals. Still, it looked boring to me and I felt uninspired. This is when I decided to hand it to Toni. If you look here, here, here, here, and here, just for starters, you’ll understand why Toni.

Toni got involved right away. Over a few weeks she gave Gourdelia a complete makeover: a corset, a fancy hat, a scarf and high-heeled shoes, and a tail. Toni opened a hole at the bottom so the hollow form could be filled with carbon for firing. Here is the clay gourd, all ready to be fired (you can click on the photos to enlarge):

Gourdelia was fired all by herself, half filled with carbon, lying peacefully on her side under an inch of carbon, at 1000°F for one hour. Then she was cooled down and fired again for 3 hours at 1470°F. Here she is yawning as she emerges from the carbon:

As you can see, some separation occurred between the copper and bronze layers, due to their different shrinkage rates. The gaps were filled with clay and Gourdelia was fired again. I won’t bore you with the details of the long finishing process. Here she is, at last, front and back:

Now Toni and I have joint custody.

Aug 22 2009

A Heartwarming Surprise

During the last days before sending my book to print, I’ve been receiving last-moment photo submissions. This one caught me by surprise. It made my day, and I can’t wait for the book to come out in order to share it with you.

Hadar's Magic Powder Earrings

Hadar's Magic Powder Earrings

Patrik Kusek sent me this photo along with the following description:

Hadar’s Magic Powder Earrings
Size: 3/8″ x 3/4″ each
Materials: Bronze Clay, Copper Clay, freshwater pearl, 14K gold, borosilicate glass vials, polymer clay stoppers, paper, inkjet ink, raw copper clay powder and raw bronze clay powder
Technique: Standard metal clay technique and wire wrapping
Photographer: Patrik Kusek

Of course these earrings are in my posession now, a gift from Patrik. Thanks, Patrik – I still can’t wipe the smile off my face.

Aug 12 2009

Sintering Issues

This is in response to many questions that I’ve been asked about failures in sintering. I’d like to remind you first of the checklist, which is available on my blog and at the end of the instruction manual. It may help you make sure that you have done everything right. I would like to mention a few more variables here:

1. If you still have sintering problems after going over the checklist, I suggest that you try carbon from a different source than you have been using. Not all activated carbons are the same. With some there will be good sintering, with some there will be partial sintering or no sintering at all, and others are only good for a limited number of firings. Unfortunately, this information is not available from suppliers and you will need to ask for samples or purchase small amounts and test them.

This is a major issue. If you have encountered this problem and do not mind sharing your reliable source please do so in the comments to this posting. I am in the process of testing a few sources but it has not been long enough to determine their reliability.

2. Your kiln may not be getting enough power. Make sure that it is connected to a circuit of its own, with no extension cords. Make sure nothing else that requires a lot of power is running at the same time.

If you are a teacher teaching a workshop and need to use a few kilns, don’t use them all at the same time. For example, if you use two kilns, run the first phase on one of them, and when it’s done run the first phase on the other. Then run the second phase with the first kiln, and when it’s over run the the second phase with the second kiln. From my experience this should not take more than 12 hours. Another option is to ask students who live close to the venue to volunteer to fire for some of the other students, as well as for themselves.

3. No shortcuts. Let the pieces cool to room temperature before you go on to the next phase. Even if you cool the box in cold water, the carbon may be still hot. Wait until you can touch it with your fingers.

4. If you use a 4″ tall box, place your pieces horizontally, as high as possible in the box. If you place them vertically, the bottom of the pieces may not sinter. For more about the box, see here.

5. Make sure that there is 1″ space between the top of the box and the top of the kiln chamber. With no space, the top of the chamber is like a tight lid, not allowing fumes and contaminants to escape.

6. For thick pieces make sure to hold one hour in the first phase to give a chance for the binder to burn.

7. Fill hollow forms halfway with carbon. Trapped air in hollow forms may interfere with sintering. Also, avoid firing more than 4 small hollow forms in one firing session.

8. If you are not sure what your full-speed temperature is, make sure that the first phase does not last less than one whole hour. If it is shorter, lower the ramp to 1750°F (972°C). Shorter firing time may cause pieces to break.

I have just fired a big hollow form (5.2 oz.) all by itself. It is safe and sound. Hope to post photos soon.

Aug 9 2009

Photos from My Workshop in Rhode Island

On the way to the class I was teaching in Bristol, Rhode Island, I stopped at Whole Foods Market. A bag of pasta caught my eye. It was pasta in the shape of calamari, which I’d never seen before. That day the class was about to make hollow forms and I thought how strange that I saw it precisely on that morning.

It was like bringing a box of candy to class. Almost everybody grabbed some to use as a mold for hollow forms. By the end of the day Jennifer Elliott had managed to finish a whole necklace of silver beads.

Other people took some home to make mixed metal hollow forms. This is the one I made:

Here are other pieces that were finished by the end of the class. Marjorie Barnes made these earrings and this necklace from copper and silver…

…which she was already wearing by the end of the class:

Marjorie also made hollow forms using rocks and rigatoni pasta as molds…

…as well as a folded hollow form from silver clay:

Sana Greene also made a folded hollow form from copper clay:

Alicia Buckler-White made a checkerboard pendant and earrings from bronze and copper clay:

Linda Busheeb made this pair of earrings combining copper and silver clay (sory for the quality of the photo):

Terri Wright made these earrings from copper and silver clay…

…and this hollow form from silver clay, with flush-set gemstones.

And Trish Connant made these three-panel earrings from all three metal clays:

By the end of the third day a lot of pieces were still waiting to be fired. All three kilns had a front door so the number of pieces fired in each kiln was limited. What I have learned in this class is that another variable that affects the sintering is the amount of power that kilns get when they are all working at the same time.