Recently I was given loads of old boxes of Orton cones some were standard and some were large but all were the same size if that makes sense..but the numbers were printed differently..After firing..Cone 8 bent more than Cone 7 tho all were set at the same angle,I have been trying to get information about firing temps of older versus newer cones and came up with this..I would be interested to know if others have inherited older style cones and had the same problem.
"In 1996 Orton reformulated some of their cones, because they could no
longer obtain the ingredients they had been using. Several mines closed
that year. According to Orton, the newest cone formulas are more
consistent the pre-1996 formulas.
Orton released the new cones on 10-28-96. Most of the changes were minor. Example: 05 became 3 deg. F. cooler.
Cones 6 & 7 had the biggest changes in temperature:
Cone 6 before 10-28-96: 2199 Cone 6 after 10-28-96: 2232
Cone 7 before 10-28-96: 2228 Cone 7 after 10-28-96: 2262