[Clayart] Homemade Cone 5 and 6

ronroy at ca.inter.net ronroy at ca.inter.net
Mon Apr 11 15:07:23 UTC 2022


I visited the Orton cone factory way back when. I'm pretty sure they  
were using red art clay. You will notice that the lower cones are  
redish - like the colour of red art - so there will be iron present to  
help melting at lower cones.

I was asking questions - like how do you get the same result when red  
art is so
variable? They told me they made a batch, made some cones and fired  
them next to standard cone they had lots of. If the cone did not bend  
properly they adjusted the batch and tried again - till the batch was  
right.

If red art is used make sure you get a bag and reserve it for making cones.

RR

Quoting David Hendley <farmpots at eastex.net>:

>
> On 4/8/2022 12:16 PM, ran mcc wrote:
>> Does anyone have a recipe for homemade cone 5 and 6 cones?
>>
>>
>
> Randy, I formulated recipes for homemade cones about 20 years ago. I  
> could make
> accurate cones (tested by firing along side commercial Orton cones).
> One point to remember: Size of the cone is important. I made plaster  
> molds from
> Orton cones for mine. If your comes are smaller they will bend too early and
> verse visa.
>
> Since I fire at cone 10, I have good recipes for cones 8, 9, and 10.  
> But, I think
> you could interpolate from them to make cone 5 and 6 cones.
> The basic idea in this temperature range is that, in the formula,  
> SiO2 is approximately
> equal to the cone number and Al2O3 is approximately 10% of the SiO2.
>
> So, my cone 8 is:
> CaO  .68
> MgO  .02
> K2O  .22
> Na2O  .09
> Al2O3  .84
> SiO2  8.41
>
> The recipe is:
> Custer feldspar  25.27
> whiting  9.39
> OM#4 ball clay  27.04
> silica  38.31
>
> Cone 10 is:
> CaO  .67
> MgO  .03
> K2O  .21
> Na2O  .08
> Al2O3  1.25
> Si02  10.02
>
> So, to formulate cone 5 and/or 6, start with the formula and set the  
> alumina and
> silica in relationship to the cone number.
> I don't think it matters too much which fluxes are involved. I  
> simply used the
> same four ingredients, feldspar, whiting, ball clay, and silica, for  
> all the cone
> numbers, and they determined the combination of fluxes.
>
> May I ask why you want to do this?
> I did it just to see if I could, and to get a better understanding  
> about ingredients
> and they way they work.
> You aren't fearing a zombie apocalypse where commercial cones will  
> be unavailable,
> are you?
>
> David Hendley
> david at farmpots.com
> www.farmpots.com
>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net




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