Advice on a kiln for fusing 17" bowl?

[Mercedes Brugh]

Hello, It's been a while. To re-introduce myself--www.FrozenMusic.net

Wondering if anyone has advice about type and size of a new kiln, and perhaps even recommendations for manufacturers. I want to work larger, 17" diameter slumped shallow bowls. I would probably fire one at a time, so am not looking for a monster kiln.

Is there an advantage to clamshells or is top-loading okay? I do not arrange the glass in the kiln or do any hotworking such as combing. Seems to me that the cheaper top loading type would work fine.

Does the square shape give even heat, or are the octagonal shapes better for evenly heating round work?

Really looking for even heat! With that in mind, how much room should be allowed between the edge of the bowl and the wall of the kiln? The top of the bowl and the ceiling of the kiln?

Have you found any advantage to elevating the bowl mold a little to allow for better air movement during firing?

Have you found an advantage to having both side and top heating elements?

I'm inclined to set up this large (for me) kiln in my unheated garage, which occasionally gets as cold as 5 below but is usually above freezing. Do you forsee any problems with that?

[Alexis Dinno]

Hey welcome back,

I use a front-loading Paragon GL24ATDTS and work in shallow bowl forms ranging from about 8" to 17". I love this kiln: super versatile! I also do casting and pate de verre on occasion, but it's so nice for the bowls.

The side elements generally come in when I am doing casting, though some techniques where I boil glass will entail side elements also.

My only problem with having it out in the garage, which occasionally sits near freezing (I am in Portland, OR), is that I have to replace one of the relays because it has got stuck about every year or so. You can find the correct relays for about $12 if you go through an electronics wholesaler (I think Paragon charges about $40), and it takes about 90 minutes to open up the controller, play with the multimeter and swap the correct relay in. This is (A) a hassle, but (B) makes me feel really badass, also. So maybe a net gain. :}

Best,
Alexis

[charlie]

I've never heard anyone say: gee, I wish I had bought a smaller kiln.

Next year, you'll want to work larger still. You should buy the largest square kiln you can afford. You can fuse a 20" round in a 23" square kiln, but you can't fuse a 20" square bowl in a 23" round kiln.

[Mercedes Brugh]

Is the cost of running a larger kiln a factor, or just the difference in purchase cost?

[charlie]

[quote="Mercedes Brugh"]Is the cost of running a larger kiln a factor, or just the difference in purchase cost?[/quote]

we don't know the power cost where you are. i know i used to pay to fire my 23" round kiln for normal fusing for $2-3/load, less if i'm not doing any annealing, more if i'm doing very thick things. i would guess a 17" one would maybe save 25% or so, but that's only .50-.75/load, so there isn't much savings.

find out what the kiln kw load is, multiply it by your power cost, multiply by your firing time in hours, then multiply again by .33 or so, since a kiln is probably on for 1/4-1/3 of the time.

[Mercedes Brugh]

Thank you, Alexis, Looked up your kiln and its replacement GL-24AD certainly is a beauty. But $2,800 is a bit high for me!

I don't expect the more modestly priced kilns to last as long as "production" kilns. I do not need a workhorse; I expect to fire this every 14 days or so--I have a smaller kiln for smaller work. The question is whether the lower-priced kilns from Olympic or Paragon, for example, would provide even heat.

Charlie, thank you. I have often wondered how to figure out the cost to fire! Glad to know it is a minor consideration in the grand scheme.

[Alexis Dinno]

Thank you, Alexis, Looked up your kiln and its replacement GL-24AD certainly is a beauty. But $2,800 is a bit high for me!

I don't expect the more modestly priced kilns to last as long as "production" kilns. I do not need a workhorse; I expect to fire this every 14 days or so--I have a smaller kiln for smaller work. The question is whether the lower-priced kilns from Olympic or Paragon, for example, would provide even heat.

Charlie, thank you. I have often wondered how to figure out the cost to fire! Glad to know it is a minor consideration in the grand scheme.

It is pricey new. But, I got mine (hardly) used for $1000, including a beautiful steel table with drawers. craigslist is your friend!

[Mark Hall]

In my opinion, your best bet is to make your own kiln. It's not rocket science, just an insulated box with elements (Durolite). The key is controlling the heat with a good digital controller, which you buy anyway. This approach allows much more size for much less money.

[lorimendenhall]

I got the Paragon-19S delivered for a little bit over $1500. It's a clamshell and can take an 18" square shelf. sounds like it's what you are looking for.

[Mercedes Brugh]

Thanks Lori. In your experience does your kiln heat evenly?

I'm fixated on this question because since 2001 I have used a jewelry burnout kiln that has elements in three walls. The first thing I had to do with this kiln was map the hot and "cool" spots, and now I have to allow for that whenever I load it. Now that I want to do these larger pieces, I want the entire lip of the bowl to have a consistent melt all around. Does that make sense?

[Alexis Dinno]

Thanks Lori. In your experience does your kiln heat evenly?

I'm fixated on this question because since 2001 I have used a jewelry burnout kiln that has elements in three walls. The first thing I had to do with this kiln was map the hot and "cool" spots, and now I have to allow for that whenever I load it. Now that I want to do these larger pieces, I want the entire lip of the bowl to have a consistent melt all around. Does that make sense?

A well-insulated kiln with ceiling elements and enough clearance below them should give pretty even heat, yes?

[lorimendenhall]

I've only used it about 5x so far but it certainly seems to heat evenly.