Wednesday, August 26, 2009

Bronze Firing Success!

Finally! Whew, that was getting really frustrating. Turns out, the problem was my kiln. This was the same kiln that I use to fire my art clay silver with no problems. However, the bronze is more finicky.

This time, I tested it out using a firefly kiln, and I ramped up 300 f per hour to 1500 f - then held for 2 hours. After which, I just shut the kiln off. The firefly I'm testing right now does not have a digital controller, just a pyrometer - Which means, you can't program it - and all changes in temperature need to be done manually, over the course of 7 hours. A digital controller is really, really needed. 7 hours babysitting a kiln is not by any stretch of the imagination fun. But I did get my studio cleaned up and organized!

The pieces came out wonderfully - perfectly fired, and sintered. Nice solid pieces of bronze!

Here are a few little worry beads I made -

I did have one failure in the batch, but it wasn't a problem with the firing, but rather with my construction. I think I mentioned before that there is a learning curve to working with the bronze - especially if you are accustomed to working with the silver clays. The construction techniques that work in silver - do not necessarily work in bronze.

Below is a hollow heart box bead that made. The box is built in three stages. Before firing, the seam was not at all visible. Obviously, my seam construction was not solid enough. I'm going to try this again being more careful - we'll see what happens.

I'm anxious to try out the copper clay now as well. My copper arrived in my mail box this morning - so by next week I should have some copper to show you!


Nathalie Girard - Canadian Rockies Art said...

Very glad you worked out the problem with the bronze clay firing.

May I ask what is the issue with your Silver Clay kiln compared to the Firefly?

What made it work in the Firefly that didn't work in your original kiln?

Your pieces are looking good - I can't wait to see what you will do with the copper!

jen said...

The kiln that I use for Silver clay has a bead door. The heat loss from it was causing the problem. It's obviously not a problem with silver clay, as I've been using that kiln for metal clay for a few years now.

If you do have a kiln with a bead door - make sure that it is very well secured, with extra fibre blankets surrounding the door.

Nathalie Girard - Canadian Rockies Art said...

Wow, talk about Bronze Clay being finicky!

Thanks for all the precious information you are sharing with us here. I'm learning a lot from you (and this will help many of us avoid costly mistakes too)