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Coating Soft Bricks For Soda Kiln

Do I need to bisque it on?

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#1 Kristin_Gail

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Posted 11 August 2013 - 11:17 AM

I'm finally set on what I'm using to coat the soft bricks in my electric-to-soda kiln conversion project.   Now I wonder:  Do I have to cook it on before I fire it with pieces inside?  

 

I've read that I need to bring it to bisque temp, empty - if so, why?  Is there a reason I can't just paint it on today, load it tomorrow with pieces,fire it (now full) the next day?  I single-fire, super-slow for the first few hours, if that makes a difference.



#2 Red Rocks

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Posted 11 August 2013 - 12:06 PM

What are you using to coat the kiln and what does the spec for the material say (if you have one?)



#3 TJR

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Posted 11 August 2013 - 05:43 PM

I agree. It depends on the coating. If it is alumina hydrate, and it falls on yor glazed ware,you will have white crudon the worst possible spor-like the rim of a teacup.

You could always bisque your pots with the coating.-Ha Ha-I kid!

TJR.



#4 Kristin_Gail

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Posted 12 August 2013 - 01:57 AM

I'm just using alumina hydrate / EPK, 50/50.  It's all painted on now, so no fair telling me I should've used something else!



#5 Kristin_Gail

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Posted 12 August 2013 - 01:58 AM

So the reason to cook it on first is just in case it's going to fall off that very first time?



#6 TJR

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Posted 12 August 2013 - 10:48 AM

So the reason to cook it on first is just in case it's going to fall off that very first time?

Yes. Alumina is very refractory. In other words, it melts at a high temperature. If it falls onto your glazed pots, you will have white crud.

TJR.

p.s. It was a good mix to apply. Basically kiln wash. Good luck with the firing.

T.



#7 Mark C.

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Posted 12 August 2013 - 12:31 PM

I would run a bisque 1st in that kiln so its shrunk some before the glaze temp shrinks it more-that way you will also see how its adhering.

I always bisque coatings on but thats me-You could also deck the whole load over with a top shelve to keep the stuff from dropping-we do that in our salt kiln always as well.

That EPK will shrink a lot as its not calcined (bisqued 1st) you want it to hold the alumina which has zero sticking power.

Mark


Mark Cortright
www.liscomhillpottery.com




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