mel jacobson on wed 18 oct 00
it is coincidental that i have had to go out and check several kilns
because they did not fire well. too much reduction etc.
in 4 cases now i have found potters firing with much to much gas.
just happened again this week with an older experienced potter.
he just did not see it.
so, it is imperative to experiment using low gas pressure and adjust
your air accordingly.
as i mentioned last year....worked on a kiln with a 20 inch flame
coming from the top peep hole. they were firing with about
8 pounds of gas and full air, huge bag walls and shelves all at
the same level....took 20 hours to fire to cone 10....i fired that same
kiln with about 2 pounds of pressure and low air in 6 hours to
cone 11.
i understand that things are different wherever you go, and a great
many variables exist. but, i find it very important to learn that
just turning up the gas does not always mean a better, faster firing.
chart the speed of temp rise with full gas, half gas, low gas.
move your damper, change your air.
observe and make simple charts.
mel
FROM MINNETONKA, MINNESOTA, USA
http://www.pclink.com/melpots (website)
| |
|
