[Clayart] Homemade Cone 5 and 6

David Hendley farmpots at eastex.net
Tue Apr 12 02:53:53 UTC 2022

On 4/11/2022 10:07 AM, ronroy at ca.inter.net wrote:
> 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

Yes, I use Redart clay for for my cone 06 cones. Since Orton cones are 
red in that
temperature range I decided to make mine red as well, by using Redart.

My formula and recipe is:

CaO    .65
MgO    .07
K2O    .11
Na2O  .17
Fe2O3  .08
B2O3   .72
Al2O3  .31
SiO2   2.22

Redart clay   48.5
Custer feldspar  9.0
Gerstley borate  28.0
whiting  10.5
total     96.0

I have been using the same batch of Redart (not just for cones) for more 
30 years, since I bought 4 bags in about 1990!

So, what ingredients are used for really low temperature cones?
When you get down to the luster firing range, cones 018, 019, 020,
the cones are white again, as are high fire cones.....

David Hendley
david at farmpots.com

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