Sunday, September 12, 2010

The Joy of Metal Clay: Copper Clay - Part 2: Metal Adventures and other brands

Last week, I talked about the Art Clay brand of Copper Clay. This week I am going to cover the other types of copper clay, primarily the Metal Adventures CopprClay which is a type that requires kiln firing in a box of carbon.

You can check back on last weeks post for Art Clay Copper.

The tools required to work with CopprClay are similar to what you would use with any metal clay. Either have separate tools for each type of metal clay you use or wash them well between uses (Exception to this is paint brushes, I have separate brushes for each clay). Personally, I can't afford to have two of everything so I just wash between types of clays (I have found that sometimes it is hard to get some of the copper colour off my textures but as long as I have washed off all the bits, I haven't had any problems. Oh, one other little thing, I have found that rolling an vegetable oil based modeling clay such as homemade Playdoh into the textures will remove a lot of the bits stuck in the textures).

CopprClay is quite a soft and supple clay. I find its texture very smooth and soft and it takes much longer to dry. It is fun to sculpt with. It is also more elastic and slower to dry which has it's pros and cons. If you are used to the quick drying feature of some of the other metal clays and you go to move your piece expecting it to hold its shape you may find it may sag and stretch. It does take longer to dry and it may warp during "speed" drying.

As I just mentioned CopprClay takes much longer to dry than silver clays (and Art Clay Copper). If you use a hot plate to dry your pieces you may find that CopprClay pieces can easily warp and become misshapen. If you are creating flat pieces the easiest thing to do is to weight it down so that the edges don't curl up (such as placing a tile or a book on top of it while it is drying on the hotplate). Otherwise you must flip and monitor your pieces in the initial stages of drying on a hot plate in order to prevent them from warping.

Firing CopprClay requires a kiln. It is achieved by by placing the pieces in a kiln safe container with activated coconut carbon (only coconut carbon, NO Coal carbon - I am not sure why but coal carbon won't work!)

There are detailed instructions here CopprClay Firing.

Here is a bried summary of firing: Once your pieces are loaded into the pan of carbon you place it on 1 " stilts (it is important to raise your box to allow air flow). The standard firing is to ramp your kiln fully to between 1700- 1800F and hold for three hours. The manufacturer warns that most pieces should sinter at 1700 and some pieces will blister at 1800F (sadly there is not clear answer and you have to figure out how your kiln fires to figure to optimal temperature for yourself ). There is also a two phase firing that the manufacturer recommends for enamelling you can check the detail on the CopprClay Firing page.

Personally, I have only tried the single phase firing and if I fire my Paragon Firefly at 1760F I find my pieces sinter properly (most of the time). I have had some occasional difficulties with firing but usually I attribute it to the fact that my carbon needed to be replaced.

Note about Carbon: Carbon contains very fine particles that become airborne when you pour or dig in your carbon. Use a dust mask and take it outside. It is surprising the black colouring that I get on my mask when I use carbon. Also Carbon will not last forever and it needs to be replaced or you may find your pieces will not sinter.

One of the positive of using CopprClay and other clays that require carbon is that there is no firescale; therefore, no pickling. I allow my pieces to cool in the box in the kiln (the carbon takes along time to cool) then I will remove them and brush my pieces with a steel brush, wash off any carbon and tumble.

Other Copper Clays

There are other copper clays out there. The only other kind I have used is Hadar Jacobson's Copper Clay that comes in a powder and you are required to mix it. It is similar to CopprClay in that it requires firing in carbon and so on but has its own set of guidelines which you can find on Hadar's site.

I know there are more brands of copper clays out on the market today. If you have tried them let me know and tell me what you think!

Hopefully this helps you in your understanding of yet another metal clay medium.


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