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Benzine

Building a Raku Kiln

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Marcia Selsor    1,301

Jon and Lee mention very important issues about working with fiber. Know what you are working with and use every precaution available.

I have built raku kilns outdoors using portable frames for pullies and counter balances. I have used telescoping channel iron for the frame.

I am on the road with an iPad and don't have the photos with me for showing examples of these.

Marcia

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Benzine    611

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

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Marcia Selsor    1,301

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

 

I think 1 1/2 - 2 inch buttons are a good size. a nub on the back rather than a loop will not crack the button as much as holes through the whole button.

marcia

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Benzine    611

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

 

I think 1 1/2 - 2 inch buttons are a good size. a nub on the back rather than a loop will not crack the button as much as holes through the whole button.

marcia

 

 

Yeah, I mispoke, I should have said nub or tab instead of loop. Two inch buttons it is. I'm thinking of twelve or so, on the main portion of the kiln. Is that enough, or would it be overkill?

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Mark C.    1,808

You can pick up an older fluke digital gauge which will read the lower temps better than an analog gauge. You will still need a thermocouple for kiln.

Mark

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Marcia Selsor    1,301

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

 

I think 1 1/2 - 2 inch buttons are a good size. a nub on the back rather than a loop will not crack the button as much as holes through the whole button.

marcia

 

 

Yeah, I mispoke, I should have said nub or tab instead of loop. Two inch buttons it is. I'm thinking of twelve or so, on the main portion of the kiln. Is that enough, or would it be overkill?

 

It depends on the size of the kiln. I would put the buttons about five inches from the edge of the blanket, and 12 " apart.

Marcia

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Marcia Selsor    1,301

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

 

I think 1 1/2 - 2 inch buttons are a good size. a nub on the back rather than a loop will not crack the button as much as holes through the whole button.

marcia

 

 

Yeah, I mispoke, I should have said nub or tab instead of loop. Two inch buttons it is. I'm thinking of twelve or so, on the main portion of the kiln. Is that enough, or would it be overkill?

 

It depends on the size of the kiln. I would put the buttons about five inches from the edge of the blanket, and 12 " apart.

Marcia

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Benzine    611

Thanks for the continued information all. I just got my order of raku clay in, so I will start making the buttons to hold the blanket. Two and a half to three inches should be good for the buttons right? And I do plan to put loops on the back, as opposed to all the way through, so the wire isn't directly exposed to the heat.

 

I will be very cautious with the fiber blanket. I plan to cut and fit it outside, while wearing a mask, gloves and long sleeves.

 

Idaho Potter, I'm sorry, I didn't see that you had already posted about shelf spacing. I should read things a little more thoroughly.

 

I still need to get a pyrometer. I was planning on just getting an analog model. I don't really need digital do I?

 

I think 1 1/2 - 2 inch buttons are a good size. a nub on the back rather than a loop will not crack the button as much as holes through the whole button.

marcia

 

 

Yeah, I mispoke, I should have said nub or tab instead of loop. Two inch buttons it is. I'm thinking of twelve or so, on the main portion of the kiln. Is that enough, or would it be overkill?

 

It depends on the size of the kiln. I would put the buttons about five inches from the edge of the blanket, and 12 " apart.

Marcia

 

 

Five inches from the edge of the blanket? What do you mean by that? Also, I am using a thirty gallon steel garbage can for the frame, so about that big.

 

I'm looking to order some raku tongs soon. The longer, forty inch, type do not have the "teeth" like the thirty inch type. Does that really matter? Obviously as plenty of people use the longer type, I would imagine they work well.

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Benzine    611

Beside needing tongs, I also need shelving. Is any type of kiln shelving adequate, or is there something that works better at resisting thermal shock?

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Marcia Selsor    1,301

benzine,

my description of the button placement is for a kiln using 1" fiber in a cube. sorry, I forgot you are using a barrel and thinner fiber.

At least put a button every 12" or so, and maybe closer to both edges of the seam.

 

For your shelf, figure out the diameter with the fiber in place. Then leave about 1.5-2" space between the shelf and the fiber. example:

23" diameter barrel, 1" fiber (2" total on both ends of the diameter) leaves 21" so 1.5-2" on each side of the shelf is 3-4" reduced from the 21"

a good size shelf would be 18" or 17" diameter shelf.

 

if you are getting tongs without teeth figure out how you will grab the necks of pots with the tongs that have curved ends and if you are going in from the top of the kiln. You might consider a hinged door on the barrel. You could use two shelves then.It isn 't difficult for a welder to fabricate a couple of hinged on a section of the barrel and a latch.

 

Marcia

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Benzine    611

I've already figured, that I should have room for a 15" shelf. Does the thickness matter?

 

I may just go for the tongs with teeth, as that's what I'm used to anyway. I can't seem to find loner varieties with teeth though. Why would that be?

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Benzine    611

So I've got most of the materials for my kiln. I've got the buttons made, and ready to be fired. One question before I attach the blanket. I was planning on adding some handles to the kiln. Will normal nuts and bolts be insulated well enough, when attached through the metal skin of the barrel? Will the insulation protect them from the heat enough, that they don't wear extremely fast?

 

I've got another question in regards to the actual firing. With the Raku firings I've done in the past, I used crumpled newspaper both layered in the bottom of the reduction barrel, and added on top. But I've also seen people layer the news paper around the interior of the barrel. What difference does this make?

Also, are there any relatively consistent results with different materials, i.e. do leaves generally lead to one type of effect, newspaper another etc? I know that the results with Raku are fairly unpredictable. but I just wondered if the components of dried leaves and other vegetation led to noticeably different results. Fall just barged in the room here, so dried leaves are plentiful.

 

I'm getting really excited to do the firing, as are my students. Lucky me, I will do a test firing first, just to make sure things go smoothly, so I'll get to see the results before they do.

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JBaymore    1,432
I know that the results with Raku are fairly unpredictable.

 

Actually American raku is FAR more controlable than most people think. The "haphazard" concept comes from people who really have not spent all that much time working with the process to learn TO control it. That is because it is so easy to just "have at it" and get pretty "flashy results" without having to really be in much control at all. Many folks don't get beyond this level of understanding, and unfortunately...... then go on to teach it to others from this basic level of understanding.

 

If you want to know about American raku control... look into books and workshops from people like Steven Branfman or Marcia Selsor. I had the pleasure of learing a bit about American raku from Paul Soldner back in the 70's. What he shared was not "haphazard" or unpredictable at all.

 

There are lots of effects that can be done repeatedly and relatively precisely. Back in the 70's when I was teaching at MassArt, I taught a course called "Fire Painted Clay", one component of which was utilizing raku as a finishing process. It involved using very tightly controlled American raku process....literally being able to "paint with fire".

 

And yes, particular combustibles do have a tendency to produce certain types of effects. You can use this as a part of learning control of the process. And as I say time and again..... test, test, test.

 

best,

 

................john

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Benzine    611

"The "haphazard" concept comes from people who really have not spent all that much time working with the process to learn TO control it"

 

*Raises Hand*

 

So from your experience, can you give me any ideas of what I could expect from different combustibles?

 

Also, what about the different methods for placing the combustibles in the reduction bin?

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Idaho Potter    62

No matter what combustibles I use (sawdust, pine needles, straw, leaves, etc) I always use a (at least) double layer of newspaper as a fairly smooth place for the pots. More newsprint on top. The bottom layers are for cushioning and prolonged combustion--the newsprint because I've found it to give the blackest blacks on unglazed clay. As John said, if you know your clay, glazes, and combustibles you can pretty much repeat the same results--at will. I have one particular glaze that gives sort of a white with blue overtones--blah. However, overfire it and you get a mauve tweed that looks good with basic black. Start with a small selection of glazes and see what happens at different temps and times. For heaven's sake, have some fun!

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Benzine    611

No matter what combustibles I use (sawdust, pine needles, straw, leaves, etc) I always use a (at least) double layer of newspaper as a fairly smooth place for the pots. More newsprint on top. The bottom layers are for cushioning and prolonged combustion--the newsprint because I've found it to give the blackest blacks on unglazed clay. As John said, if you know your clay, glazes, and combustibles you can pretty much repeat the same results--at will. I have one particular glaze that gives sort of a white with blue overtones--blah. However, overfire it and you get a mauve tweed that looks good with basic black. Start with a small selection of glazes and see what happens at different temps and times. For heaven's sake, have some fun!

 

 

No worries about the fun part. I will indeed have some fun. If I didn't think I was going to, I wouldn't have taken the time to get all the kiln parts and put it together.

 

Can you get different results with the underglaze? I was the under impression that any exposed clay, or clay like material, like underglaze is stained black during the reduction.

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Benzine    611

Yes, if you have a good reducing atmosphere in your container, all the unglazed surfaces should be black.

Marcia

 

 

That's what I thought. My students are all pretty underglaze happy, so I was planning on telling them, to not even bother for the Raku firing. At least now I know, that such a declaration is completely accurate.

Do oxides do anything interesting during the Raku process?

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Marcia Selsor    1,301

I just fired a nice (IMHO)tile with underglaze using a thin clear raku glaze. I like it. It came out with a slight crackle effect wit un underglaze colors true to their color.

Marcia

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Benzine    611

I just fired a nice (IMHO)tile with underglaze using a thin clear raku glaze. I like it. It came out with a slight crackle effect wit un underglaze colors true to their color.

Marcia

 

 

Interesting.

 

Do you think there is any chance that a normal low fire clear glaze would work? I swear I tried it in the past, but I don't recall the result.

I really like the crackle effect that Raku can offer. Is there a good way to obtain this, other than just using a glaze specifically formulated to crackle?

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Benzine    611

I'm putting the kiln together, cutting the fiber blanket and such. First, that blanket is indeed nasty stuff. I took precautions, in regards to my lungs and eyes, but even gloves and longs sleeves were not enough to prevent that stuff from poking though to my skin at times. It's like fiberglass insulation, if fiberglass insulation swore a vendetta against you, and everyone you care about.

 

Anyway, is there a preferred way to attach the buttons? It is very difficult to line the wire up, with the holes I drilled. Any suggestions?

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Cass    5

number12.gif

 

all of my work is clear crackle, commercial lowfire glaze...i dont underglaze, but i know it works

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Benzine    611

number12.gif

 

all of my work is clear crackle, commercial lowfire glaze...i dont underglaze, but i know it works

 

 

That's very nice.

What is the brand of clear crackle you buy?

 

The crackle effect is what first intrigued me about Raku.

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Marcia Selsor    1,301
I know that the results with Raku are fairly unpredictable.

 

Actually American raku is FAR more controlable than most people think. The "haphazard" concept comes from people who really have not spent all that much time working with the process to learn TO control it. That is because it is so easy to just "have at it" and get pretty "flashy results" without having to really be in much control at all. Many folks don't get beyond this level of understanding, and unfortunately...... then go on to teach it to others from this basic level of understanding.

 

If you want to know about American raku control... look into books and workshops from people like Steven Branfman or Marcia Selsor. I had the pleasure of learing a bit about American raku from Paul Soldner back in the 70's. What he shared was not "haphazard" or unpredictable at all.

 

There are lots of effects that can be done repeatedly and relatively precisely. Back in the 70's when I was teaching at MassArt, I taught a course called "Fire Painted Clay", one component of which was utilizing raku as a finishing process. It involved using very tightly controlled American raku process....literally being able to "paint with fire".

 

And yes, particular combustibles do have a tendency to produce certain types of effects. You can use this as a part of learning control of the process. And as I say time and again..... test, test, test.

 

best,

 

................john

 

I fired my first raku with Paul Soldner back in 1967 in the snow!

Marcia

 

 

 

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