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reduction in an electric kiln


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Those don't appear to be kanthal elements.  

If you have a kiln with silicon carbide elements you can do this with zero problems.  I've seen videos of these in china and italy.  The silicon carbide element thing isn't really common here in the US.  I think kiln manufacturers make too much money on replacement elements to manufacture kilns with silicon carbide elements ;)

Edited by liambesaw
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1 hour ago, akilspots said:

reduction only for a part of the firing?

I think as @liambesaw said .... and silicon carbide elements are a bit harder to design with and likely more money. As to reduction and time  it’s a look thing dependent on the glazes and to some extent the clay body. Reduction will get oxygen from anything and everything it can, including kiln bricks if reactive. So less time generally would be less wear and tear but very dependent on the desired look to achieve ........ and the glaze composition. Also one can achieve reduction but if the atmosphere changes to oxidation too soon, one can oxidize and erase the reduction or reverse the process so there is that component to how long and at what level to remain in reduction. 

looks like he reduces iron mainly And I did enjoy the open all the windows bit.

Edited by Bill Kielb
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Pyromax doesn't say much, there are traditional FeCrAl alloy and silicon carbide elements made under that trademark

I'm going to guess they're either ceramic coated or silicon carbide.  The photos of their pyromax ceramic (silicon carbide) look similar to the elements in his kiln.

If you reduce in a kiln with FeCrAl elements, the protective oxide coating starts getting small holes and pits in it, which (ahem) "reduces" the life of it quite quickly.  

One of the reasons being you typically reduce during a glaze firing, and then the next firing is... A bisque firing!  So you have the unoxidized pits from the glaze firing, and then you immediately bombard it with water and strong acids.  Very tough. One thing you can do to mitigate it, and I've read this from people who reduction fire with a bunsen burner in oxidation, is to put an extra firing up to cone 04 in an empty kiln after each reduction firing.  I don't know if there's any science behind that, but theoretically it may reoxidize the pitted areas of the element.  In my mind, the pitting is damage and will affect the mechanical strength.

 

Definitely experiment with it. But do it when you start noticing your elements going downhill, so you won't be damaging healthy ones.

 

 

 

 

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19 hours ago, liambesaw said:

I think kiln manufacturers make too much money on replacement elements to manufacture kilns with silicon carbide elements ;)

There is likely some truth to that, but mostly it's because the cost would go way up, and price many customers out of the market. Kanthal elements are a decent balance between cost, longevity, and ease of construction.

It would definitely help if the kiln was only reduced for part of the firing. One thing that you can do to help with element life is to do an oxidation firing between reduction firings to build up a new layer of protection on the elements. I would think that only reducing for part of the firing would have a similar effect, rebuilding the protective layer after the reduction is done.

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4 minutes ago, Mark C. said:

Seems so much easier to just fire with gas for reduction

Easier if you're in a place where you can set up a gas kiln. For most people it's not possible where they live.

The easiest solution is simply to formulate your clay and glazes so you don't need to reduce to get the effects you want.

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