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Hi Guys,

 

Well, after much study on the subject, I decided to design a tatara featuring attributes of what has worked for members here, as well as this book I got from Japan.

Thanks to all of you for sharing your info, and experiments.

 

My criteria are:

It has to be cheap, quick, and easy! Oh and as short as possible due to my location.

Since I am hopelessly addicted, it also has to be reusable, or at least easily remade.

 

I decided to use a sand cement mix like Mr. Hernandez, and cast custom "bricks". Obviously the fewer molds, the better. So I got it down to 6 pieces.

 

I also get this knot of envy in my stomach when I look at Niko's results in his rectangular tatara. highly motivational! ;) So I want to go with that more traditional shape wide mouth.

Thank you Niko for your help so far.

 

I got this radioactive Wakou guide book from Japan hoping it might have the secrets to the perfect smelt in it. Well, it may, but I can't read it. So I focused on the pictures. :)

 

I did figure out the measurements for the tueyres...200 mm. So I added that in as well.

 

here's what I came up with so far. It's easy to manipulate at this point, so I wanted to give you guys a chance to critique it, and make suggestions before I make the molds for it.

 

Any info is greatly appreciated.

 

Thanks,

Robin

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Thanks for posting this as I'm working on a similar project.

 

Are the purple bricks that support the tuyeres going to be made from the same material? Are they designed to be slid out to access the bloom?

 

I too want a re-usable furnace... preferably a permanent one, but it sounds like even with Jesus's Catalan the interior will get destroyed by the bloom and slag adhering to the walls. Any thoughts on how to prolong the life?

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I like the design. A couple of suggestions... avoid using cement in the mix. Use the more traditional clay, sand and straw (or similar). Some of those bricks are long. I don't know of anything that will make a permanent furnace. They all need to be repaired or rebuilt at one time. So with that in mind, the simplest the design to be built, the better.

Edited by Jesus Hernandez

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Robin Hi.

 

 

 

Bigger furnace has at least one heads up issue more....You WILL need lots more charcoal and ore!

Just to fill up the bigger furnace will "eat" huge amount of charcoal + and after this you will need more to run it.

So if your ore amount is not "big"...its easyer to make smaller furnace and run smaller blooms.

Say if your plan is run 80kg or more ok...but under 30kg I would make smaller. Smaller desing could be just wider bore and cylinder shape.

 

Im with Jesus, some bricks are long and there is risk of cracking.

Whit clay and sand and even more traditional method...making smaller "hit-bricks" and slapping them in place

might have some effect of wear resist and heat resist also...mass is compressed more than cast ones..if you dont use any weight after casting.

 

I think it looks good :)

 

Niko

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Ok, interesting responses so far. Thanks guys

.Sounds like tueyre (sp?) heights, wall height, and wall thickness are good then.

 

Using clay instead of cement unfortunately makes reusability impossible.

 

Thanks for posting this as I'm working on a similar project.

 

Are the purple bricks that support the tuyeres going to be made from the same material? Are they designed to be slid out to access the bloom?

 

I too want a re-usable furnace... preferably a permanent one, but it sounds like even with Jesus's Catalan the interior will get destroyed by the bloom and slag adhering to the walls. Any thoughts on how to prolong the life?

 

Scott,

the idea was to cast all the pieces in the cement sand mix Jesus has used in the past. That would make replacing melted parts easy. I figured the lower blocks with the tuyreres in them would melt away like the real deal and I could cast a couple more for the next run.

 

Jesus has advised against using cement however, and I'm dying to know why.

 

 

I like the design. A couple of suggestions... avoid using cement in the mix. Use the more traditional clay, sand and straw (or similar). Some of those bricks are long. I don't know of anything that will make a permanent furnace. They all need to be repaired or rebuilt at one time. So with that in mind, the simplest the design to be built, the better.

 

Hi Jesus, thanks for the tips, and inspiration.

 

I have to ask, why you say no to the cement/sand?

We are using your mixture now(minus the vermiculite) on another smelter. Should we discontinue that as well?

Does it add contamination to the steel? Or is it some other reason?

 

When I see pics of japanese tatara, it looks like the clay from ceramics class. Would something like that work?Do you have a suggestion of clay that might be closer to the real stuff?

 

Again, Thank you Sir :)

 

 

Robin Hi.

 

 

 

Bigger furnace has at least one heads up issue more....You WILL need lots more charcoal and ore!

Just to fill up the bigger furnace will "eat" huge amount of charcoal + and after this you will need more to run it.

So if your ore amount is not "big"...its easyer to make smaller furnace and run smaller blooms.

Say if your plan is run 80kg or more ok...but under 30kg I would make smaller. Smaller desing could be just wider bore and cylinder shape.

 

Im with Jesus, some bricks are long and there is risk of cracking.

Whit clay and sand and even more traditional method...making smaller "hit-bricks" and slapping them in place

might have some effect of wear resist and heat resist also...mass is compressed more than cast ones..if you dont use any weight after casting.

 

I think it looks good :)

 

Niko

 

Hi Niko,

We normally run about 30kg of ore, but I wonder if running 80kg might give better results due to the thermal mass of all that steel? Do you think that makes a difference?

 

I am guessing about 400 lbs of coal to run 160 lbs of ore?

 

Obviously I could make this a 12"x12". That would save on clay, build time, and coal.

 

Yeah if I go with the clay I may as well make it the traditional way: small clay bricks slapped together and smoothed to form tatara.

 

I guess I need to see what the price of clay is, and that will help make the decision for me.

 

Thanks again for your help and advise :)

 

Anyone else, please feel free to add to the discussion :)

 

Thanks,

Robin

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Robin,

 

As you have guessed, I suspect that cement can contribute unwanted elements into the mix.

 

Jesus

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Robin,

 

As you have guessed, I suspect that cement can contribute unwanted elements into the mix.

 

Jesus

 

Thank You Sir :) That little bit of info just saved me much grief.

 

OK, plan B. it is then.

 

Robin

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Anyone have a suggestion on a good clay to use for constructing the tatara. I have read that ball clay may be right. I can get it pretty cheap too.

Can anyone comment on this?

 

Thanks,

Robin

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here is my understanding , it could be off . ball clay is a low melt clay and as such would be good to use as a sacrificial lining but not so much thew whole structure.

slag can be really really distructive so make sure that all gaps at slag level are sealed well or it'll eat its way out on you !!

I would be concerned about the size as that will be a really hungry tatara.

as the size increases the risk does but from what I have sen of the results from big tatara can be much better as far as consolidated bloom is concerned .

also why the V12 layout , my limited experience has been that so many small tues mean a hell of a lot of problems and unblocking and possable gumming up.

It will be a great undertaking though either way.

all the best Owen

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Robin,

 

As you have guessed, I suspect that cement can contribute unwanted elements into the mix.

 

Jesus

 

Jesus what leads you to believe that ?

all the best owen

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Hello,

I agree it is quite big... maybe cut it in half for a first try, and scale up once you are confortable with the process?

For clay I just use the local grey-blue clay we have here. Kaolin clay seems to be the best according to friends.

Good luck!

 

Antoine

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Jesus what leads you to believe that ?

all the best owen

 

 

Just a suspicion, Owen. A bloom that never consolidated (it continuously cracked) and some input from Skip made me change my ways. Although I have not had any problems previously.

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Jesus what leads you to believe that ?

all the best owen

 

 

Owen,

 

I may not know very much about smelting, but I know a little about cement making.

 

One thing I can tell you, is that modern cement usually has sulfur in it - both as a by-product of production and as a direct additive in the form of gypsum ( CaSO4 ), it may also have it in the form of slag, that is often added.

 

 

If it was something that I just had to use, it would be in the form of a pure lime cement, which is a little harder to come by.

Edited by Greg H.

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Anyone have a suggestion on a good clay to use for constructing the tatara. I have read that ball clay may be right. I can get it pretty cheap too.

Can anyone comment on this?

 

Thanks,

Robin

 

Ball clay usually has minerals such as mica in it that are often sodium, potassium, or calcium based, which means a lower maximum temperature that the clay can handle. Less often the mica might be based on titanium magnesium or others which can handle the temperatures but can also cause other problems for the smelt.

 

 

A flint based fire clay is supposed to do a good job, while kaolin is supposed to be about the best.

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here is my understanding , it could be off . ball clay is a low melt clay and as such would be good to use as a sacrificial lining but not so much thew whole structure.

slag can be really really distructive so make sure that all gaps at slag level are sealed well or it'll eat its way out on you !!

I would be concerned about the size as that will be a really hungry tatara.

as the size increases the risk does but from what I have sen of the results from big tatara can be much better as far as consolidated bloom is concerned .

also why the V12 layout , my limited experience has been that so many small tues mean a hell of a lot of problems and unblocking and possable gumming up.

It will be a great undertaking though either way.

all the best Owen

 

 

 

Hi Owen,

Thanks for the input. Ithink I will cut the size of the tatara by half. I found this tatara built by the man himself. It's actually a very informative blog about making tatara start to finish if you guys care to look. So I took a lot of ideas from this.

 

 

 

http://nataliealt.blogspot.com/2009/12/tatara-part-one-preparation.html

http://nataliealt.blogspot.com/2010/01/tatara-part-two-real-thing.html

 

Anyway, they are using 6 tuyere for a 12"x12" so I doubled it for 12"x24".

 

Ok So I have decided to go for basically what you see in the pic above. A 12 x 12 x 48 seeing as I am using an unknown variable (clay).

 

from the description above they are using a gravely/claylike substance.

 

I called my local ceramic shops trying to find out what kind of clay would work, and they were not much help. They said its not possible, it will explode, and never dry, use bricks, blahblah.

 

However one of them suggested maybe a kaolin/ball clay/silica mixture..? He could not give me a ratio though.

 

I'm guessing 1 to 1 silica(sand) to clay, and just enough ball clay to get it to stick together?

 

What do you guys think of that mix?

Sorry for focusing on what kind of clay so much, but I don't want waste any more money than I have to experimenting, or add some unwanted impurity to the steel.

 

Thanks again for all the help. Hopefully everyone will benefit from the discussion :)

 

Robin

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Ok So I have decided to go for basically what you see in the pic above. A 12 x 12 x 48 seeing as I am using an unknown variable (clay).

 

from the description above they are using a gravely/claylike substance.

 

I called my local ceramic shops trying to find out what kind of clay would work, and they were not much help. They said its not possible, it will explode, and never dry, use bricks, blahblah.

 

However one of them suggested maybe a kaolin/ball clay/silica mixture..? He could not give me a ratio though.

 

I'm guessing 1 to 1 silica(sand) to clay, and just enough ball clay to get it to stick together?

 

What do you guys think of that mix?

Sorry for focusing on what kind of clay so much, but I don't want waste any more money than I have to experimenting, or add some unwanted impurity to the steel.

 

Thanks again for all the help. Hopefully everyone will benefit from the discussion :)

 

Robin

 

When kaolin is heated over 1000* F, it's atomic structure changes to mullite ( refractory ) which has a melting temperature a little over 1800* ( in pottery terms, it becomes porcelain, firing at a cone 11-14 which is hotter than most common pottery will take ).

 

If you add ball clay it will lower the melting temperature, which is something that many folks prefer, as it also means that it both the firing temperature and the over all melting temperature ( lower cost of fuel to fire any give piece of pottery ).

 

 

Here is one source Kaolinite

 

A couple of links that you might read over and keep in mind while you are thinking this over:

http://pottery.about.com/od/potterygloassary/g/kaolin.htm

http://pottery.about.com/od/typesofclays/tp/midrange.htm

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When kaolin is heated over 1000* F, it's atomic structure changes to mullite ( refractory ) which has a melting temperature a little over 1800* ( in pottery terms, it becomes porcelain, firing at a cone 11-14 which is hotter than most common pottery will take ).

 

If you add ball clay it will lower the melting temperature, which is something that many folks prefer, as it also means that it both the firing temperature and the over all melting temperature ( lower cost of fuel to fire any give piece of pottery ).

 

 

Here is one source Kaolinite

 

A couple of links that you might read over and keep in mind while you are thinking this over:

http://pottery.about.com/od/potterygloassary/g/kaolin.htm

http://pottery.about.com/od/typesofclays/tp/midrange.htm

 

Hi Greg, Thank you for the input:) Just wanted to say thanks real quick.

 

I will check out those links and get back to you guys here.

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When kaolin is heated over 1000* F, it's atomic structure changes to mullite ( refractory ) which has a melting temperature a little over 1800* ( in pottery terms, it becomes porcelain, firing at a cone 11-14 which is hotter than most common pottery will take ).

 

If you add ball clay it will lower the melting temperature, which is something that many folks prefer, as it also means that it both the firing temperature and the over all melting temperature ( lower cost of fuel to fire any give piece of pottery ).

 

 

Here is one source Kaolinite

 

A couple of links that you might read over and keep in mind while you are thinking this over:

http://pottery.about.com/od/potterygloassary/g/kaolin.htm

http://pottery.about.com/od/typesofclays/tp/midrange.htm

 

 

Ok Greg I have digested the links you gave me. That's exactly what I needed to get a better idea of the different clays and uses. Thanks.

 

Thanks to both Antoine and Greg...Sounds like Kaolin is the stuff I want.. Maybe I will add some sand .

 

So.... kaolin epk or kaolin 6 tile? what do you guys think?

 

I guess I was just having a hard time believing that I already have a hundred pounds of the stuff I need in my garage. Man it never works out that way for me.

 

I am actually in the process of making a HT forge out of Kaolin EPK,. Just waiting for it to dry..

 

Hmm maybe it's a good omen eh?

 

I think I have enough info to move forward on this project. Of course feel free to add anything you think may help.

 

Thanks to everyone for the input and advice. I will keep you all updated as things progress.

 

Robin

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No big deal - I went through the same " what materials to use " process a couple of years ago and spent a couple of months researching it and I'm just passing what I learned on - now I'm kind of playing with the idea of lining the area around the tuyere with a zirconium dioxide ( melting point of over 2500* ) hot face - which in theory should improve thermal efficiency, since ZrO2 reflects heat.

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