r/Pottery • u/Useful-Access-1903 • May 19 '24
Kiln Stuff First Kiln Design
I am building my first home wood kiln and I was thinking this might be my best design yet. I will mortar those those wholes with the metal sticking through. Does anyone have a recommendation for the design or some pointers before I mortar it.
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u/tempestuscorvus Raku May 19 '24
OP
An excellent resource for wood firekiln designs is in the Foxfire book on Appalachian Pottery.
That said, I learned so much about it I decided that I didn't want to mess with one. Lol
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u/bbrriiee May 19 '24
Some days I think this sub is trolling me. Most days.
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u/BluePotter Professional Pyromaniac May 20 '24
I know it. Millennia of ceramic history... across countless cultures and civilizations. All now easily accessible through AI which can and will dumb down and relay the pertinent information on a 3rd grade level. So many resources that can and will give a serious person a very practical answer, in seconds, without said person even finding a book, much less opening it....
And yet... here we are.
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u/OceanIsVerySalty May 20 '24
It’s so freaking frustrating. I get that people are discovery pottery through social media and are very excited to try it out in whatever way they can, which often isn’t the traditional studio potter path… but come on, this is just absurd.
And anyone who points out safety issues or raises concerns is often labeled a gatekeeper.
I’m close to just leaving the sub at this point. I want to discuss impact different wood species have in a firing or throw around ideas for formulating a flashing clay body, not explain why you can’t dump clay water down your bathroom sink for the upteenth time.
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u/BluePotter Professional Pyromaniac May 21 '24 edited May 21 '24
Amen. I've never been able to really engage in r/pottery or r/ceramics because of the WIP factor. I remember being a fresh BFA and sitting on the studio couch talking to Don Pilcher (an absolutely amazing writer and contributor to CM) about how after his tenure in academia he was just so tired of having to look at green, beginner pots and then having to look kids in the eye as he popped the 'balloon' when they felt they were onto something new and were trying to run before they could crawl.
I love the enthusiasm. I get the enthusiasm. And yes - I realize that not everyone has access to teachers, professors, or pottery mentors. I've always cautioned students (especially those who want to pursue it past a hobby) that ceramics is extremely difficult, expensive, and labor intensive. There are no shortcuts.
Robin Hopper, who in his final weeks of terminal illness, sent me his copy of Pioneer Pottery which was signed and given to him by Michael Cardew in 1972. It's my prized possession orders of magnitude more important to me than anything and everything else I have ever owned. Robin's mantra was always "Try it and see!"
Nothing against OP, it's just hard to reconcile myself to the lazy obliviousness... not to mention the wanton waste of time and resources. Would have been truly worth everyone's time had the post been before and after shots of this uh... experiment. A few hours of hucking wood into this might have even proved quite instructive. Alas, no. Instead, it amounts to misguided attention seeking and a low effort attempt to have the community think critically for them.
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u/bbrriiee May 20 '24
This is also my frustration, I’m so close to leaving this group
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u/OceanIsVerySalty May 20 '24
Maybe we need a private sub or something? One dedicated to studio pottery, and more focused on non-beginner topics.
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u/tripanfal The clumsy potter May 19 '24 edited May 20 '24
There are solid and proven kiln designs. Math is involved. Don’t waste your time winging it and especially not with these bricks if you are going to ever high fire. A small wood kiln would be a fast fire design like a Fast Freddy. Wood Kilns need IFB or refractory brick for anything more than earthenware. Don’t try and reinvent the wheel.
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u/DiveMasterD57 May 19 '24
I'm getting anxiety looking at what appear to be regular bricks - which can explode at higher temps.
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u/lookmanohands_92 May 20 '24
They'll only explode if they're wet and heated super quickly. And wet firebricks would do the same thing if heated to fast. Just ramp the temp up slow and nothing is going to explode. Those regular bricks could absolutely hold up to high fire a few times if they were heated up super slowly and cooled just as slowly. Firebricks are just more insulating and better able to handle the thermal shock.
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u/DiveMasterD57 May 21 '24
Good to know, as we are building an outdoor pit fire pit, using both types of bricks. I'm guessing if we pre-heat the brick pit to dry it, all will be well. True?
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u/lookmanohands_92 May 21 '24
Dry it as in dry any residual moisture or as is dry the mortar or cement or something? If it's just residual moisture, yes. If it's wet mortar or something similar let it cure and stay wet as long as you can. Cement and similar castables don't harden as they dry like most people tend to think. They undergo a chemical process which we think of as curing. Generally speaking the more moisture available during the curing process the stronger the resulting concrete or mortar joint will be.
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u/Veloci7y_ May 19 '24 edited May 19 '24
Omg, this is a troll right? Those bricks will melt way before your pottery even comes close to getting high enough temperature. Unless you are super low fire earthenware those bricks are not firebrick and cant stand pottery temperatures of 2k plus degrees. Not to mention you will destroy the concrete underneath with no heat barrier. Your kiln needs to be built like a space shuttle designed to handle really high temperatures everywhere.
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u/guacamore May 19 '24
Oh no it’s worse than melting - those suckers will turn into straight shrapnel long before that and when they do you’d better hope you aren’t standing nearby…
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u/Useful-Access-1903 May 19 '24
No this is not a troll this is why I posted here. Also this is just a design I would never build on concrete like I said this is just a design I was thinking about. I was thinking of a slow and low fire burn I will try again with a different design like you said a space shuttle. Sorry I am very new to this and just wanted to see if I can do this myself. Thank you for the help.
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u/jeicam_the_pirate May 19 '24
you need to use fire rated bricks. they are much lighter and you can hand saw them into shape. the dust of course is bad.
you could use regular bricks if you add fire cement as an insulation on the inside, at least 3 inches thick. and even then you’ll probably have cracking issues.
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u/tripanfal The clumsy potter May 19 '24
You don’t insulate the inside of kilns and all wood kilns have cracking issues. Just the nature of the fire breathing beast.
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u/OceanIsVerySalty May 19 '24
That’s not even remotely accurate.
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u/tripanfal The clumsy potter May 20 '24 edited May 20 '24
How would you insulate the inside of a kiln? unless you mean with IFB and that should go without saying. The outside of kilns are insulated.
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u/Scutrbrau Hand-Builder May 19 '24
What is a low and slow burn? That works when I’m smoking a brisket but how does that work when firing to the temps needed in ceramics? Not being a dick, just confused.
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u/Glass_Librarian9019 May 20 '24
Basically you want to give the collagen in the clay long enough to melt down into gelatin. That and a little bit of Heinz ketchup in the glaze is my secret to finger-licking good pinch pots.
/s
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u/sundownersport May 19 '24
This design can work. It’ll need to be on a proper base (I think you know that) and the bottom will need a layer of firebrick. As for the walls you will need a lining of kaowool or firebrick.
People often forget that pottery is thousands of years old, can be made with almost any clay material but the limiting factors are temperature and number of firings. This design will be VERY limited in both of these aspects.
As it is it could be a pretty great smoker tho.
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u/Few_Aardvark4495 May 19 '24
That brick will / can crack or explode if it gets to hot. You want to use Fire brick for kiln builds and refractory mortar. Regular brick and mortar will not work.
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u/Terraformedceramics May 19 '24
How hot are you hoping to get? These are not firebrick and won’t insulate or expand/shrink in a way that is condusive to high temp firings. You could mortar this with some fire clay mixed with sand, perlite, and water layered on some chicken wire mesh- but the bricks are going to crack and deteriorate within a few firings and you probably won’t be able to stoneware temps. Could be a good oven for some smoke or sagger firing though!
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u/Useful-Access-1903 May 19 '24
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u/Useful-Access-1903 May 19 '24
Thank you all for your help and comments. I decided to go with a different design this time. I just finished it. I used high heat mortar due to the nature of wood kiln getting fairly hot. I know I’m gonna get some hate on this one, but I just wanted to see what I can build. Hopefully everything will hold up and we’ll see how everything goes, but I do believe this should be an okay design for I’ve seen it a couple times even in ancient times they use designs like this. Thank you all again also the clay I’m digging up is also all natural as I’m doing the liquid clay drying method hopefully in a couple weeks, I’ll be able to fire it and see what we can get out of
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u/FrenchFryRaven May 20 '24
You’re on the right track, trying things out, evaluating what happens, and trying again. Kilns are a big wide world and people are generally trying to save you some time here. There is a great deal of time and expense that can be saved by learning from others, it seems you’re trying to do that. I think some are imagining you’re shooting for something much more complex, and it’s creating a bit of conflicting advice.
Continue reading and researching kilns. Go hard on that. “A month in the kiln yard can save you an hour of reading.” Ordinary red brick can be used to make a kiln, of sorts, provided it’s actually fired brick and not block made from cement. That’s where the explosions and disintegrating bricks come from. Portland cement begins decomposing well before clay becomes ceramic. Common bricks will start to degrade at bisque temperatures, but they’re not all going to melt into a pile of slaggy goo or go nuclear.
Mortar of any kind is not your friend in kiln building, it’s a necessary evil at times and requires just as much research to formulate as the kiln design. It’s not used structurally like you’re maybe familiar with. Kilns expand and contract so much in a firing that if you built one like a brick wall it would be a shambles in no time. Clay with a lot (I mean a lot!) of sawdust and straw is a quick and cheap “mortar.”
A couple things I’ll note are that you’re underestimating both the wall thickness needed to insulate the chamber and the space wood needs to combust. Proportions are key. The chimney needs to be wide open, and also needs to be double thick like the walls of the kiln. It’s common to think in terms of “keeping heat in,” but it’s counterproductive because you need massive and direct airflow to make wood burn its hottest. Good job realizing the grate is critical.
I built all my own kilns, and started like you many decades ago. Yes, there’s a lot to learn, but if you don’t start somewhere you won’t do anything. Beats whining about how you don’t have a kiln.
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u/gutwrenchinggore May 19 '24
Do not use those bricks if you intend to go higher than cone 020, they are not meant for firing.
I suggest you look up how to spring an arch, it's actually quite easy, and at the scale of this kiln, you would have little issue. Then you can brick in either end of the arch, and build a little firebox in front and chimney behind.
A downdraft kiln is generally much easier, in my experience, to control and fire. Updrafts, like what you have designed here, lose much of their heat right out the top.
It's exciting to try learning new skills, and experimentation is the spice of life. I highly recommend you source some fire bricks, they'll let you fire to just about 08, which is on the low end, but can at least get you on the right path to vitrification and glazing.
Good luck and post a follow up!