[Clayart] Old old old cones

Kathleen Schultz k1claylady at aol.com
Tue Oct 25 21:16:14 UTC 2022

David, Thanks for the info! I found that a really old box of large Orton cones had this stuff on the surface. I had started using the self supporting cones and this box got stuck in the back of the drawer. When I fire a bisque again I’ll see what happens with one of them compared with the self supporting one. I’ll only be able to see one through the peephole but will see the result when I open the kiln. All the other older cones showed no sign of anything on the surface. 
Kathy Schultz 🌴

Sent from my iPad

> On Oct 24, 2022, at 5:33 PM, David Woof <woofpots at hotmail.com> wrote:
> Hi Kathy,
> A simple test of the viability of older cones is to set them side by side in a firing with a setting of new cones.
> As you may know, cones are a formulation of ceramic materials and fluxes that soften and bend at a predictable rate for a given "heat work" maturation of the glaze, or clay body (or to best advantage both.)
> Cones that are compromised by age, and more often by moisture will give evidence on their surface of flux mineral migration to be redeposited on their surface.
> As an FYI, as in Egyptian paste self-glazing, or the scum that migrates to the Earthenware clay body surface from soluble minerals in the clay, so also with the mineral composition of cones over extended time on the shelf.
> (To mitigate this scumming, usually additions of up to 1.5 barium carbonate is added to these clay bodies.)
> So if the old cones appear "scummed" toss them!!!
> Also be aware that large cones and the small cones of same cone number designation may be as much as a half cone difference in indication of "heat work" attained.  Same test: fire a setting of small cones , next to a setting of large cones.
> Misneach,
> David Woof....................................................................................................................................................
> **************************************************************************************
> ________________________________
> From: Clayart <clayart-bounces at lists.clayartworld.com> on behalf of Kathleen Schultz <k1claylady at aol.com>
> Sent: Sunday, October 23, 2022 8:03 AM
> To: Clayart international pottery discussion forum <clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] Old old old cones
> Since I have cones that are more than ten years old, that is good news! It never occurred to me that cones could age.
> Kathy Schultz 🌴
> Sent from my iPad
>> On Oct 22, 2022, at 10:23 PM, Paul Lewing <pjlewing at comcast.net> wrote:
>> On Oct 22, 2022, at 12:58 PM, Roxanne Hunnicutt <roxhun at gmail.com> wrote:
>> I’ve received information that asserts OLD CONES are less accurate!
>> Is that even a little bit true?
>> No.
>> Paul Lewing
>> www.paullewingtile.com<http://www.paullewingtile.com>  <http://www.paullewingtile.com/>
>> www.paullewingart.com<http://www.paullewingart.com> <http://www.paullewingart.com/>
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