Firing Glass in a Ceramic Kiln
Reader Response: The sound of relays
Recent Q&As: Recommended brand of crimping tool; R and S type thermocouples
News: Kiln Drawing at NCECA Conference
FIRING GLASS IN A CERAMIC KILN
By Dianne Carter
Spirit of Fire
I have been firing glass pendants, business card holders, cabochons, and earrings in my Paragon SC-2 jewelry kiln. When I realized that my creativity was outgrowing my SC-2, I went to the garage and took a long, hard look at my big beautiful Paragon TnF-24 ceramic kiln sitting all alone in the corner.
Most of the reading that I have done on firing glass in a ceramic kiln suggests firing in the mid-level area. I fire glass using a schedule designed by Paul Tarlow of www.heliosglass.com.
Before loading the kiln, vacuum the entire inside including the lid. Vacuum the kiln after each firing as shelf paper turns to a fine dust and is hazardous to inhale. I use a Shop Vac with a HEPA filter. I wear a 3M 8577 Particulate Respirator P95 mask when vacuuming.
The loading instructions are for a 29” deep ceramic kiln. You will need to experiment to find the best shelf placement for your kiln. Align posts vertically between shelves.
1) Start by placing 6 - 1" posts on the floor of the kiln in the appropriate places to support 2 half shelves. Place 2 half shelves on the posts leaving a 1" gap between the two shelves for heat circulation.
2) Place a full round shelf on top of 6 - 12" posts. Place Bullseye Thin Fire shelf paper on the shelf.
3) Add the first pieces of glass to the shelf. Scatter a few pendants around. This is a great way to find out how similar pendants fire at three different shelf heights.
4) Place 1 half shelf on top of the 3 - 5" posts.
5) Place 3 - 8" posts in position to support one more half shelf. Place a sheet of Bullseye Thin Fire shelf paper on each 1/2 round shelf. As you can see, I have created a bi-level shelf system for better heat circulation. If you do not do this, glass on the top shelf will full-fuse. Place a fusing project on each half shelf and again scatter a few pendants on each shelf level.
6) Close the lid of the kiln and, of course, place the Kiln God (made for me by a dear friend) on top of the lid to watch over this firing and to keep the glass "happy."
I prefer a dimensional fuse for these pieces, so they will have character. I also fire it slowly as I have 3 layers of glass.
Paul Tarlow’s Firing Program (degrees F): Segment 1 / RA1: 250 per hour / SET 1: 1000 / Hold: 60 minutes Segment 2 / RA2: 250 per hour / SET2: processing temp / Hold: 4 minutes
Segment 3 / RA3: 970 (let drop on own to 970) / SET: 970 / Hold: 60 minutes (glass getting "happy") Segment 4 / RA4: 120 per hour / SET4: 700 / Hold: 0 minutes I have had some exciting projects come from tweaking the hold time at the top and speed of temperature rising and lowering through segments. I have also had some disasters, which happened more often in the beginning when I forgot how patience plays a huge part in successful firing. Don't cheat and open the kiln too soon unless you like the sound of breaking glass! Remove the Kiln God before opening the lid. Yes, he has been flipped off the kiln in excitement! Open the kiln to joy and wonder. Have fun, and keep your glass HAPPY!
(Visit for additional photos of Dianne’s glass firing project, visit Paragon's Facebook page
Last week’s Kiln Pointer was about relays. Ann Davis of Washington, DC wrote, “Hey, thanks for the great explanation of the relay. I LOVE that clicking on and off . . . reminds me of the little engine that could saying, "I think I can, I think I can."
Q. Can you please tell me the brand and model of crimping tool featured in your recent Kiln Pointers? The tools I've seen are quite sizable and look awkward.
A. The crimping tool is a Klein 1006. It is a durable tool.
Q. What is the difference in R and S type thermocouples?
A. The R and S type thermocouples are both made of platinum / rhodium wires. The R type has 13% rhodium / 87% platinum for one conductor, pure platinum for the other conductor. The S type has 10% rhodium / 90% platinum for one conductor and pure platinum for the other conductor.
The main difference between the R and S type thermocouples is that the R delivers 15% more mV than the type S. They are both rated to the same temperature. We sell the type S. The only reason we don't sell the type R is that it is almost the same as the type S.
“I used to have this wonderful haiku pinned up above my kiln when I had my studio: ‘Now that my house has burned down, I have a better view of the rising moon.’
“During firing, I would lose stuff that I had made. Things I thought would be beautiful turned out ugly. The haiku helped me realize that I had to live with loss and ‘failure’ and learn from it.” --Sandra Dwiggins
NEWS: KILN DRAWING AT NCECA CONFERENCE
Paragon is holding a drawing at the NCECA pottery convention for a free Caldera XL kiln. You can sign up at Paragon booth #530. No purchase is necessary, of course. We will choose the winner on Friday, April 2. The Caldera XL is a 7 1/2" square x 9" deep top loader rated to 2350 degrees F. It fires on 120 volts. It has a digital controller and is fairly beefy, with 3" bricks.
Maria, the receptionist at Paragon, is one of the most courteous people I know. Yesterday she turned 21. Her mother, eyes glistening, came to the office and gave Maria red roses and a balloon. There is something magical in a parent celebrating a child’s birthday.
With best wishes,
Arnold Howard Paragon Industries, L.P. – Better Designed Kilns 2011 South Town East Blvd., Mesquite, Texas 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 / firstname.lastname@example.org / www.paragonweb.com
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