As I mentioned in a previous post, these holidays I have been working my way through Hadar Jacobson’s books. I put quite a bit of work into two bracelets and they came out look like this! I wanted to give up metal clay completely. A week later I think I can talk about it… and try another firing;) I this post I outline what I did last time and what I propose for the next one.
Firing schedule
I have a Paragon SC3 and used the following firing schedule (Rio Grande via MSchindel’s excellent Squidoo Lens).
BRONZclay pieces up to and including 3mm (6 cards) thick*:
Program the kiln as follows:
Ramp at 500°F (278°C) per hour to 1550°F (840°C).
Hold for 2 hours.
(Total firing time, including ramp-time, will be between 4 and 5 hours.)
Cool before removing lid/unloading.
The ‘bricks’ (pictured left) were a quarter of an inch thick so clearly needed to be fired longer. [Problem 1] What I still don’t get though is that not all the pieces were that thick but everything failed.
Rapid Cooling
This is the first time I have been awake when the kiln finished. Normally I put it on overnight. Impatience got the better of me and I took the pan out while it was still very hot and dug around with a pair of tongs. [Problem 2] I couldn’t work out why I wasn’t picking up the linked bracelet. Finally I worked out it was turning to powder as I stirred.
I have a few copper pieces that need firing and a repaired bronze piece so I will try re-firing the bricks.
I’m going to try the following based on instructions in the article on CoolTools:
Ramp: 253 F (137 C)
Target Temperature: 1530 F (830 C)
Hold 3 hours.
It is a much slower ramp. It will be going all night. I will also leave it until mid morning to have a dig around.
Wish me luck!
