Saturday, May 18, 2013

Pattern Bars -- My First Firing at Home

If you read my recent article about taking a pattern bar class, you know how exciting it was for me ... and for everyone in the class. I couldn't wait to make another one immediately! This time I chose turquoise and gray glass and cut eight 1" x 12" strips of each color. I made two stacks of 8 pieces, alternating colors. These were tack fused, same as before. I decided to use the same pattern as the first piece and cut 16 1" pieces. I built my 7" square dam, lined it with 1/8" fiber paper and set the pieces in. Here's my first photo:

I checked and double checked before firing ... everything seemed to be okay, but .... sh*t happens, doesn't it? Something went wrong, but the piece still is very nice.

After a closer look, I saw three pin holes that were pretty large and could not be ignored. I called Ron at Stained Glass Supplies and he said to come down and get a jar of clear glass powder. He called the instructor before I got there and I was told to sift on a thin layer and fire to 1480, holding for 10 minutes. And to fire the piece in the dam. I rebuilt the dam with new fiber paper around the piece and refired it. The next morning when it had cooled, I opened the kiln and was SOOOOO disappointed to find my piece all crusty looking! It looked like it was underfired. What should I do? I didn't like the underside of the piece even though it had a nice satin finish.

I decided to search the internet for firing temperatures for this clear powder, since the jar had no information. Surprisingly I found nothing. I finally called the manufacturer and spoke to someone who asked a lot of questions until he really understood my problem and then gave me his opinion on my next step. Simply put on a thicker layer of the powder and refire to the same temperature of 1480, but hold for 30 minutes. WAAALAAA! I knew his suggestion was correct. This piece fired beautifully with a glossy finish. You can still see the pin holes, but they are filled. Next time maybe I'll grind some of the same glass and try fill each hole?

Here is the piece completed after firing it in a mold.

For those of you who have a ceramic kiln and want to fire glass .... YES, you can do it. I have been doing it for years. It takes a lot of test firings and record keeping. Your firing is done on one shelf where the probe is just above the shelf with your glass piece.

If you have any questions on my pattern bar firing, don't hesitate to contact me. I'll be happy to share my firing schedule. There is a lot of information on the Bullseye website, as well as searching for Bullseye on YouTube.

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