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Hi Ceramic Arts Community.  I have an opportunity to custom build a kiln, made by a start up company that, to date, has only made very small (20cmx20cmx25cm interior) kilns.  The company is a one man operation.  That said, he has been working as a kiln repair technician for many years and is the brother of a good friend of mine.  I have concerns about the specifications of the kiln and figured maybe this community might have some advice:  Interior dimension 40cm x 40cm x 40cm and exterior 65 cmx 65cm x 65cm.  So that gives a wall thickness of only 12.5cm (just under 5").  The target temperature is 1240 celcius and it will be top loading on wheels.  Power is 220v and wattage will be 6200 watts.  The controller will be a novus n480d and the lining will be kiln brick on top and bottom and I believe 3 layers of 1400 degree celcius soft insulation. Powder coated metal exterior.  Anyhow, the price is about 30% cheaper than an established brand but honestly, not sure if I want to be a guinea pig even if it makes me disloyal to a good friend by not supporting his brother's newish business.  Sorry for the long post.  Any positive or negative feedback about the kiln specs (are the walls insulated enough) ;  or other experiences with "home made" kilns is appreciated.  Thanks in advance.

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IMO

A kiln is really a pretty simple thing.  It's mostly just a box after all.  It really comes down to quality of materials.  My kiln is ceramic fiber interior propane downdraft, so I'm familiar with soft fiber interior.  If that's what he's planning, I'd pass on it.  I don't see how you could use fiber for a hot face on an electric kiln.  Now if he has a soft brick face backed with fiber, I would probably like it a lot. 

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Fiber and electric coils (elements) can be problematic. They do burn out and with fiber replacing them will tear upo the fiber. Thats why 99% of the kiln manufactures use soft bricks or at least one good reason. The few fiber kilns that are electric I have seen do not make it possible for element replacemeant without damaging the fiber. I would ask i about this one issue as it important in the long run.

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Thanks for the replies. From what I understand, the floor and lid will be brick, the sides will be fibre.  I appreciate your comments that this construction could be problematic in replacing the elements. Also, I believe the only vent will be at the top, in the lid, if that makes a difference too....no downdraft...I will ask the manufacturer to ensure that soft brick is what is in contact with the elements.  Should I be concerned that the kiln is not insulated enough with walls 12.5 cm (4.92 inches) thick?  Thicker walls means more efficient and cooler exterior, right?

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4 minutes ago, Vidya said:

Thanks for the replies. From what I understand, the floor and lid will be brick, the sides will be fibre.  I appreciate your comments that this construction could be problematic in replacing the elements. Also, I believe the only vent will be at the top, in the lid, if that makes a difference too....no downdraft...I will ask the manufacturer to ensure that soft brick is what is in contact with the elements.  Should I be concerned that the kiln is not insulated enough with walls 12.5 cm (4.92 inches) thick?  Thicker walls means more efficient and cooler exterior, right?

The walls of my high efficiency kiln are 3 inches so you should be fine there ;)

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If he's got a good system for attaching the elements to fiber walls, it could be fine. Elements in grooved soft brick are the most common method, so that's why we're questioning how he plans to do it with fiber. It could be he's got a perfectly good system. The only fiber walls I've seen have the elements buried into rigid fiber wall modules. The elements sit just below the surface, you can't actually see them when the kiln isn't on, and the elements can't be replaced- you have to replace the entire wall module. The kilns I've seen that on were small glass kilns, where elements are hardly ever replaced because they just don't wear out at the low temps they fire to. Brick walls would be more durable.

The other consideration is whether or not the kiln needs to be listed/safety certified for where you're installing it. In the US, kilns installed in schools and other public spaces generally need to be UL listed (or equivalent), and landlords will often require it as well. So check into that, because a custom kiln will not be certified.

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I really don't like unsealed ceramic fiber as a hot face.  First off, the fiber material shrinks, so the joints will need to be repaired at some point depending on the design.  The fiber material is VERY fragile.  Any bump  will cause a injury releasing micro fibers.  Worse to breath than clay dust, I'm told.  Yes, it's a great insulator and makes a very efficient kiln, but you have to have a plan for how to repair it as time goes on.  I haven't seen the design of this kiln, so I can't really offer a definitive opinion, but I don't see how you could get a comparable life to a brick kiln.  I have something like 50-60 firings on my home built ceramic fiber propane downdraft and it's had several significant repairs.  The interior is sprayed with kiln mortar to give some protection to the fiber, but it doesn't hold up 100%. 

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vidya, never worry that you are saying too much in any post on this forum.   you have to give enough information to make the question clear so you can get a correct answer.

if you ask for more info on the design, you might find that the maker plans to put the elements in only the floor and roof.   you, as the potential buyer have a right to know everything about that experimental kiln.  read the websites of the big kiln makers in your country and see what details they mention.  ask your maker for a plan so you are able to have someone check out the specifications for you.

you really do not have enough information to go on yet, be cautious and remember that  neil is a kiln expert and follow any suggestions he makes.

i wonder why you are mentioning "downdraft".  this is an electric kiln, right?  (volts and watts)  nothing is burning inside it so what kind of draft are you imagining?

Edited by oldlady
clarity
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ya know I would pass on it and get the kiln you want. I just don't see how in the world it is remotely disloyal to a friend that has a brother in the business to not buy what is essentially a prototype kiln. You buying a kiln from this guy is not going to be what makes his business a success and it sure sounds like to me it has the potential to be a negative 'thing' with your friend down the road if you end up doing this out of some kind of loyalty thing and it ends up being a crappy kiln that you have a lot of issues with. He does not need friends of relatives to be his customers to be successful in his new venture he needs to design and build a kiln that the market as a whole accepts and buys into. He needs total strangers to pick his kilns when they are shopping for kilns. 

Also you are right to not want to buy a prototype  kiln because these early kilns are very likely to be redesigned as he goes.  Better for him and you that those early customers be strangers that he only has a business relationship with. He might have to pretty much give a few away to get a track record and some traction. 

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Thanks Neilestrick.  I confirmed with the guy it's 3 layers of fibre and then a brick on the inside layer of the kiln.  It's going to be used on my own, well ventilated property with concrete floors....so I am not worried about it being certified by a safety authority.  I do have another question though, but perhaps it is suitable for another forum topic....how do people keep their cats from jumping on the kiln, while not confining the kiln to an enclosed space while it is firing? Kid and animal proofing....

I thought I had posted the above reply yesterday.  Since then, Old Lady and Steven have written.  I really appreciate all the support and words of advice. Old Lady: sorry for the confusion re "downdraft" .  I know there are electric kilns that have holes in the top and bottom, with a vent fan drawing air out....so I was replying to another comment.  But I really am taking Stephen's well considered and detailed reply to heart:  better that the start up sells prototypes to strangers.  The only thing is, he already makes small, high temperature kilns and has been building his market for at least a couple years.  It was I who asked him if he could build a larger high temperature kiln....it may be he is uneasy about venturing into new territory too.  I kind of agree re price though....I was expecting a price that was less than 70% of a well established brand that also has lifetime technical assistence by phone.  Yeah, not sure if I want to risk it.  I will definitely satisfy myself that he knows what he is doing and I will enquire about warrantee and services for repair and maintenance.  Thanks again for all the feedback!  

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1 minute ago, Vidya said:

Thanks Neilestrick.  I confirmed with the guy it's 3 layers of fibre and then a brick on the inside layer of the kiln.  It's going to be used on my own, well ventilated property with concrete floors....so I am not worried about it being certified by a safety authority.  I do have another question though, but perhaps it is suitable for another forum topic....how do people keep their cats from jumping on the kiln, while not confining the kiln to an enclosed space while it is firing? Kid and animal proofing....

I thought I had posted the above reply yesterday.  Since then, Old Lady and Steven have written.  I really appreciate all the support and words of advice. Old Lady: sorry for the confusion re "downdraft" .  I know there are electric kilns that have holes in the top and bottom, with a vent fan drawing air out....so I was replying to another comment.  But I really am taking Stephen's well considered and detailed reply to heart:  better that the start up sells prototypes to strangers.  The only thing is, he already makes small, high temperature kilns and has been building his market for at least a couple years.  It was I who asked him if he could build a larger high temperature kiln....it may be he is uneasy about venturing into new territory too.  I kind of agree re price though....I was expecting a price that was less than 70% of a well established brand that also has lifetime technical assistence by phone.  Yeah, not sure if I want to risk it.  I will definitely satisfy myself that he knows what he is doing and I will enquire about warrantee and services for repair and maintenance.  Thanks again for all the feedback!  

If he's looking to start making larger kilns, he should consider doing this first one at just above his cost so he can work out any issues and use it for advertising purposes. This is not really a very large kiln, only 16" interior, so some of the problems that come from larger kilns won't be an issue on this one. Specifically, I'm thinking of the weight of the lid. On a 27" kiln you have to have a very good hinge system. On a 16" kiln it's not a big deal.

There's no good way to keep a cat off a hot kiln other than letting him jump on it when it's hot. Chances are he won't want to jump on it when it's hot, though. As for when it's not hot, jsut put something on it that feels bad on their paws, like a piece of chicken wire.

Fiber behind brick will be very well insulated, but find out how easy/difficult it will be to replace broken bricks. I'm assuming it will be a square kiln with a full metal box? Typically with that type of construction all the bricks are mortared, which makes replacement very difficult. You've got to take good care of it.

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I see what looks like darker mortar between the bricks.

That kiln in photo is super insulated .Thats good thing.  Looks like stainless outer jacket as well-well made.The bad thing is the lid is all fiber (the lid is shollow so its looks like no bricks in lid) and the fiber seal is really exposed so over time  (loading and unloading) will wear that out as its subject to abrasion.The kiln in photo looks to be specialty test kiln.

That large fiber area will over time bet really brittle where heat gets to the edges and be subject to injury. It would be better for the brick to come up flush with lid surface so you are loading shelves in and out of brick surfaces. For an occasional fire this may not matter but for lots of firing it will degrade.

I'm with Neil your kiln is a learning experiment  for the maker to some degree so the cost should reflect that

Edited by Mark C.
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The established brand (see pic) will cost the equivalent of around 2500 usd and itvus front loading, whereas the prototype will be around 1750 usd.  Maybe it is safer to go with the more expensive and more reliable kiln.  Or....maybe I can suggest changes to the prototype design and try to get a better price....

IMG-20191030-WA0001.jpg

IMG-20191030-WA0000.jpg

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Oooops Marc C.  I was wondering where you saw the name Itvus.  Hahahaha.  Sorry, it was a tipo and should have read "

The established brand (see pic) will cost the equivalent of around 2500 usd and IT IS  front loading, whereas the prototype will be around 1750 usd.  Maybe it is safer to go with the more expensive and more reliable kiln.  Or....maybe I can suggest changes to the prototype design and try to get a better price....

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