[TBm]

Hi, all.

I expect to build my own odd-sized kiln (after I work out many details), and am told that it is possible to build DIY either a natural gas kiln or an electric kiln... If building an electric kiln is not really feasable, please warn me off now, before I dig myself a hole (which is my 3rd kiln option, LOL).

Hypothetically:

- Kiln A is a long, low cross-draft natural gas kiln 4'W x 4'H x 8'D.

- Kiln B is an electric kiln of the same dimensions.


Firing both to Cone 10, can someone give me an idea of how the costs would compare?
Here's a rough idea of my current rates:
Electric kWH = $0.07 summer and $0.09 winter
Natural Gas = $0.85 per therm

Any advice much appreciated,
Tom

[hansen]

TBm, on 02 June 2010 - 03:09 PM, said:

Hi, all.

I expect to build my own odd-sized kiln (after I work out many details), and am told that it is possible to build DIY either a natural gas kiln or an electric kiln... If building an electric kiln is not really feasable, please warn me off now, before I dig myself a hole (which is my 3rd kiln option, LOL).

Hypothetically:

- Kiln A is a long, low cross-draft natural gas kiln 4'W x 4'H x 8'D.

- Kiln B is an electric kiln of the same dimensions.


Firing both to Cone 10, can someone give me an idea of how the costs would compare?
Here's a rough idea of my current rates:
Electric kWH = $0.07 summer and $0.09 winter
Natural Gas = $0.85 per therm

Any advice much appreciated,
Tom

Tom: kiln "b" is beyond the recommended specs for most electric kilns. Proximity to the elements is crucial. You could overcome this limitation by adding insulation, but you're probably better off with the natural gas not only from the stand-point of dimensions of planned kiln but also cost of energy. Your most economical kiln is a natural gas fired, folded fiber-blanket updraft construction. See Hank Murrow's web site at: murrow(dot)biz
h a n s e n

[TBm]

hansen, on 02 June 2010 - 03:34 PM, said:

Tom: kiln "b" is beyond the recommended specs for most electric kilns. Proximity to the elements is crucial. You could overcome this limitation by adding insulation, but you're probably better off with the natural gas not only from the stand-point of dimensions of planned kiln but also cost of energy. Your most economical kiln is a natural gas fired, folded fiber-blanket updraft construction. See Hank Murrow's web site at: murrow(dot)biz
h a n s e n

h a n s e n ==

Thanks for the link and the insights. I'm glad to hear that the gas kiln is the better (or only) choice. I've been doing a little reading and it appears electric heating elements are prone to "issues"...so gas it will be, I guess.

Hank Murrow's lift kiln is a thing of beauty, but waaaay beyond my means. Is there something else on his site I should be seeing?

I'm very curious about your "folded fiber-blanket updraft construction" suggestion. Does a folded fiber blanket somehow take the place of typical (and EXPENSIVE) refractory brick. I know, that's probably too much to hope for, but...

I scoped out Fred Olsen's The Kiln Book some months ago, but didn't buy it. Now it's out-of-print and the price has skyrocketed. That's the 3rd Edition. Do you happen to know if a 4th Ed. is due out soon?

Thanks,
Tom

EDITED Next Day: I googled the fiber blanket concept. Found plans and info for raku kilns made from oil drums, etc. but can you help me determine whether a fiber blanket approach is a reasonable alternative to refractory brick when firing stoneware to bisque and then cone 6-10 glaze/final?

[hansen]

TBm, on 02 June 2010 - 10:20 PM, said:

hansen, on 02 June 2010 - 03:34 PM, said:

Tom: kiln "b" is beyond the recommended specs for most electric kilns. Proximity to the elements is crucial. You could overcome this limitation by adding insulation, but you're probably better off with the natural gas not only from the stand-point of dimensions of planned kiln but also cost of energy. Your most economical kiln is a natural gas fired, folded fiber-blanket updraft construction. See Hank Murrow's web site at: murrow(dot)biz
h a n s e n

h a n s e n ==

Thanks for the link and the insights. I'm glad to hear that the gas kiln is the better (or only) choice. I've been doing a little reading and it appears electric heating elements are prone to "issues"...so gas it will be, I guess.

Hank Murrow's lift kiln is a thing of beauty, but waaaay beyond my means. Is there something else on his site I should be seeing?

I'm very curious about your "folded fiber-blanket updraft construction" suggestion. Does a folded fiber blanket somehow take the place of typical (and EXPENSIVE) refractory brick. I know, that's probably too much to hope for, but...

I scoped out Fred Olsen's The Kiln Book some months ago, but didn't buy it. Now it's out-of-print and the price has skyrocketed. That's the 3rd Edition. Do you happen to know if a 4th Ed. is due out soon?

Thanks,
Tom

EDITED Next Day: I googled the fiber blanket concept. Found plans and info for raku kilns made from oil drums, etc. but can you help me determine whether a fiber blanket approach is a reasonable alternative to refractory brick when firing stoneware to bisque and then cone 6-10 glaze/final?

[hansen]

Exactly. Folded blanket exceeds soft refractory brick for its insulating qualities. The design Hank developed is a means of holding the folded fiber in places, I believe it is buttons of refractory material and kanthol wire, but look at it from an expedient point of view. Soft insulating brick has structural qualities in and of itself, you can build a kiln out of it by itself. You could drape and fasten fiber blanket over it. The Olsen book is only a starting point, as the exact dimensions of the various ports and flues relative to the cubic foot dimensions of the interior. As well as burners, etc.; has huge ramifications on how the kiln behaves in firing. A natural up-draft might be the first construction, maybe forced air (blowers) a second project, downdraft a third. (with stack) Bricks are probably the best way, being modular, to discover and work out all of this by yourself -

but raku kilns with one thin layer of blanket won't get you to high temp. Not at all.

Hard brick is another option if all this is going on in the out of doors -
h a n s e n
p.s. maybe the easiest kiln to build might be the sprung arch updraft out of soft brick

hansen, on 08 June 2010 - 06:41 AM, said:

TBm, on 02 June 2010 - 10:20 PM, said:

hansen, on 02 June 2010 - 03:34 PM, said:

Tom: kiln "b" is beyond the recommended specs for most electric kilns. Proximity to the elements is crucial. You could overcome this limitation by adding insulation, but you're probably better off with the natural gas not only from the stand-point of dimensions of planned kiln but also cost of energy. Your most economical kiln is a natural gas fired, folded fiber-blanket updraft construction. See Hank Murrow's web site at: murrow(dot)biz
h a n s e n

h a n s e n ==

Thanks for the link and the insights. I'm glad to hear that the gas kiln is the better (or only) choice. I've been doing a little reading and it appears electric heating elements are prone to "issues"...so gas it will be, I guess.

Hank Murrow's lift kiln is a thing of beauty, but waaaay beyond my means. Is there something else on his site I should be seeing?

I'm very curious about your "folded fiber-blanket updraft construction" suggestion. Does a folded fiber blanket somehow take the place of typical (and EXPENSIVE) refractory brick. I know, that's probably too much to hope for, but...

I scoped out Fred Olsen's The Kiln Book some months ago, but didn't buy it. Now it's out-of-print and the price has skyrocketed. That's the 3rd Edition. Do you happen to know if a 4th Ed. is due out soon?

Thanks,
Tom

EDITED Next Day: I googled the fiber blanket concept. Found plans and info for raku kilns made from oil drums, etc. but can you help me determine whether a fiber blanket approach is a reasonable alternative to refractory brick when firing stoneware to bisque and then cone 6-10 glaze/final?

[TBm]

h a n s e n ==

I don't mean to drag you through another slog. but am not sure I understood your last transmission. When/if you reply, may I suggest you delete my entire quoted remarks from your reply - for the sake of clarity? Too bad this forum doesn't allow us to choose whether to reply with-or-without quoted remarks, on a per-reply basis.

Defining terms: I assume your use of the terms fire brick, refractory brick and soft brick all refer to the same material. And you seem to have said the fiber blanket insulates better than those bricks. Am I right?

Here's where I get quite lost: Are you saying the folded insulating blanket can be substituted in place of brick? Or that it cannot? I'm speaking in terms of firing Stoneware to Cone 7 maximum. Or perhpas you're suggesting wrapping the fiber blanket around the outside of a stacked refractory brick kiln - in order to maximize the bricks' temperature-holding ability.

It seems to me a lightweight metal frame--perhaps a rebar armature constructed on the outside--with the insulating blanket attached to the underside of the armature might contain the heat well enough to keep the rebar from melting. Would such a "wigwam" not be far lighter, more easily reconfigured and more easily moved than stacked brick?

I appreciate your help (and patience),
Tom