Cone

No.

Temp.

Composition

K₂O

M_gO

C_aO

B₃O₃

Al₂O₃

SiO₂

1

1080˚C

1978˚F

0.06

1.3

0.42

0.6

0.3

2.8

2

1200˚C

2192˚F

0.2

0.1

0.7

0.1

0.46

3.5

3

1230˚C

2246˚F

0.2

0.1

0.7

-

0.4

3.5

4

1410˚C

2570˚F

2.8

1.3

6.6

11.6

8.4

46.5