Tiny Dancer

I bet you looked at that top piece in the last post and thought "What the heck?"

This piece was made by draping and folding a thin sheet of copper clay as if it were a piece of fabric.  There was no idea in mind when I started (so what else is new) but as I looked at the piece it had a fluid feel to it which reminded me of a dancer.  I added a head at the top, carved into the leg area to add to the movement and finished it off with a pink sapphire.

Working with the clays is like opening a present at Christmas.  The piece changes so much from it's dry leather hard stage to the finished metal piece when it comes out of the kiln.  (Once in a long while, it's a big letdown.  Things happen in the kiln that are not pretty.  That's when I have flashbacks to the robotic sweeper my husband got me one year for Christmas.  Those who know me, know that story.)   Then, it's Christmas again when I take the flex-shaft to it to polish it up.  What a difference!

I hear music when I look at this piece.

Fresh out of the kiln

These aren't the pieces in the previous post, but they are copper and they are fresh out of the kiln.  This is the first time that any of my pieces have shown any kind of color after firing.  Usually they have been a very dull brown color.

Sometimes the colors that appear on copper and bronze are worth saving. In order to do that it is necessary not to polish them or the color will be lost.  Eventually the color will just darken and disappear as the metal tarnishes.  But, as you can see, the color on the large piece is definitely not worth saving. My friend Carol Scheftic ( http://convergentseries.wordpress.com) has been getting some nice colors on her pieces lately and check out the gorgeous bronze pieces at (http://gaillannum.blogspot.com.)

Firing copper clay

In a previous post I mentioned how copper and bronze clay have to be fired in an oxygen free environment.  This also applies to steel clay, rose bronze clay and the new PMC Pro (a stronger form of silver clay that has some copper in it for strength.)

There are various containers for firing these clays.  I use a stainless steel container that gets a black coating on it during firing that is messy and dirty.  (My vacuum cleaner is seeing the light of day more often now.)  Even though there are containers that don't get a black coating I figure that I already had a container and might as well use it.  It's been working great so why mess with a good thing.

My friend Carol Scheftic takes a photo of her pieces before they go into the kiln so that if something goes wrong she knows where it was located in the container and thus may be able to figure out why the piece did not sinter.   I've started to do this too.   (It also helps my brain remember how many pieces are in there. ) It's not obvious when the firing is done because a one inch layer of carbon is covering the top.

Here's a photo of a load before firing.  Because the pieces need to be toward the back of the container the number of pieces that can be fired are minimal.  (Unlike silver which is fired on an open shelf.  Several shelves can be stacked with ceramic spacers between them which allows for even more pieces and the silver can be placed anywhere on the shelf.)  Because the firing time is shorter and there are more pieces in a firing, silver is much cheaper to fire.  But, much more expensive to buy.  I'm still trying to figure out if the cost of working with the base metal clays are really any cheaper in the long run.

Copper firing schedule

As you can tell by my latest posts, I've been dabbling in copper clay; specifically Hadar's powdered clays.  Several years ago I took a copper clay class from Debra Weld.  In that class we worked with CopperClay which is in lump form.  It was the very first copper clay to be introduced to the metal clay world.

True to my usual self, I had several pieces laying around from that class that had not yet been fired.  (Didn't have to worry about whether they were dry enough or not.)  According to Hadar, her firing schedule would work on all the clays, so I thought I'd give it a try.  It certainly does work.

This piece also was textured with a tear away texture that Debra had available in class.

Hadar suggests firing the clay in a two-step process.  The first firing burns off the binder and the second firing sinters the metal molecules.   First firing is 1100 degrees for a time of 30 minutes to two hours; depending on the size of the pieces and the amount of binder to be burned off.  The second firing is 1650 degrees for two hours.  (That's the schedule for copper.  If using copper and bronze together the second firing is 1520 degrees for two hours.)   

Firing is done in an oxygen free environment.  This is accomplished by firing in an open container that contains powdered charcoal.  (All charcoal is not created equal, so I used Hadar's to be sure.)  There's a half inch of charcoal underneath the pieces and an inch above the pieces.  Since I have a muffle kiln, I have to position my pieces towards the back of my container.  (The area by the door is cooler.)  After the first firing has cooled down, the thin layer of burned charcoal is blown off the top.  Then more charcoal is added to to the container to make sure there is enough on the top before starting the second firing.  

In the past I've had some copper firings that did not turn out.  (The water in the tumbler turned a pretty metallic color as the pieces disintegrated.)  So far this method has been the most successful for me.   

Copper and Bronze clay

     As was mentioned in my previous post, I've revisited working with copper and bronze clay.... via Hadar Jacobson's powdered clays.

     A little over a week ago several of my friends and I had a play day to try out the clay. Ginnie Weltner, who is a frequent student and friend and my college roommate, Cindi Armstrong  (who visits every Labor Day weekend and is a once a year student) helped me test out the powdered clays.

     We each mixed our own clay and tried Hadar's "inlay" technique which is one of the first projects in her most recent book, Pattens of Color in Metal Clay; Canes, Gradients and Mokume-Gane.   My friend Carol Scheftic has a photo of two of her pieces in Hadar's book.  One of them is the inlay project.  The book is worth checking out.

     The inlay project is made by rolling the copper clay to the thickness of two popsicle sticks, impressing a deep texture or object into the clay, filling the depression with the bronze clay and sanding the piece to expose both of the clays in a level surface.  (Now I know that my description is not very detailed and it's not meant to be.  For more detail, check out Hadar's book.)

     For the most part it's not working with the clay that stresses people out but the firing process, which I'll talk about in another post.   Luckily, both my test piece and the final pieces fired successfully at the recommended temperatures.  

     The only thing I noticed was that the bronze appeared to be more porous looking and had small cracks in it.  (It wasn't the same in all the pieces which could be attributed to us each mixing the bronze clay differently.)  I also know  I wasn't as careful mixing the bronze as I was the copper and felt that we all had it a little drier than it should have been.  (Another learning experience!)  We could repair the cracks and re-fire the pieces.  (Which we don't plan on doing as they were very small.)

     The final step was to apply Baldwin's Patina to the highly polished and cleaned pieces.  Baldwin's Patina is specially formulated to work on copper and bronze.  I found it worked best when the piece was warmed up in very warm water.  (Otherwise the clay just seemed to suck the patina right in.  It didn't do that in the video!  Hadar's blog offers a video on how to apply the patina.)   The patina highlights the contrast between the copper and the bronze.

     So far, the only thing I do not like about using the bronze and copper clays is that they are very dirty to work with.  Using liquid gloves does help keep the hands cleaner, but somehow the darn stuff manages to still get under the fingernails and the dark dust is everywhere.

     I have several other pieces ready to be fired before I decide for sure whether I like this clay or not.  They all use the drape method and will be much lighter in weight than the inlay pieces.  I'll keep you posted.

Slow down!

The copper firing done on Thursday was definitely a learning experience. The first rapid firing netted great results. This one did not.

Nothing cracked like I thought it had. The cracking sound was a couple of balls popping off a piece. Other than that, everything looked great.

I brushed them and threw them in the tumbler. (Copper clay should have it's own barrel for the tumbler.) They tumbled for a couple of hours. Opening the tumbler is always like opening a present at Christmas. The first two pieces came out shiny and bright. The third piece had half of it's decoration missing! My first thought was that it cracked off, but it was not to be found in the tumbler anywhere. What was found instead was a nice coppery liquid at the bottom of the barrel. It disintigrated! So, I started to wonder. I took a pointed tool and started to dig at the rest of the decoration and sure enough it was soft like the original clay but had a copper crust on the top. The entire decoration came off easily.

Then I tried another piece that had a decoration on top. It looked great, but once I started digging, it turned to powder. Wow, how did that happen?

My thoughts on this is that the decorations were still wet. The base pieces had been dry for over two months. These pieces were put on the night before and I mistakenly thought they would be dry by the next day. Wrong!!! They were really, really thick pieces and obviously it takes more than a day to dry. The base pieces were fine, it was just the decoration.

For some reason it is best to air dry copper (and I presume bronze clay). For that reason I did not use the usual candle warmer or dehydrator.

I did take pictures, but don't know how to get them onto my son's computer. When (and if) I get my laptop back, I'll be sure to share.

Lesson learned....... you can't hurry love (oh, sorry that is a Diana Ross song) copper clay.

Also, the Open house is not going to pay for my computer repair. It will pay for my mailings and food but that is all. Don't ask..... it's a sore spot!

It's Christmas tomorrow

Finally got around to firing my finished copper pieces. I only had three of them done but decided that I might as well get them fired. If I waited until they were all done it could be next year.

Copper clay is fired in coconut charcoal (no, it's not acorn charcoal!) The charcoal has to be fired for three and a half hours before using it. Not sure why, that's just what I was told.

I've heard all different methods of firing the copper clay, but went with the method that Jan Durkin (from my metal clay guild) used. I fired the pieces flat on a shelf for one hour at 500 degrees F. As soon as they were cool enough to handle, I put them in the stainless steel container on top of one inch of the charcoal. All the pieces were laid around the center. Then I poured the rest of the charcoal on top, (used a one pound bag) and ramped the kiln at full speed to 1650 degrees. I fired them for three hours and forty-five minutes. (The directions were for one hour and thirty minutes but I just thought I'd be different.)

I did learn that my kiln won't get to 500 degrees and hold for one hour if I use full speed. I had to use speed number two (500 degrees per hour) for it to work. Using full speed kept shutting my kiln off as soon as it reached temp. (Hopefully this isn't an omen of more problems with my controller. The book never has my problem listed.)

Now begins the wait. The kiln is supposed to cool down on its own, so I just left the studio without peeking. Hopefully all works out well. We'll see tomorrow. The anticipation is just like Christmas. I'll share (hopefully good news) tomorrow night.