[Clayart] fast firing protocol
wschran at cox.net
Tue Oct 4 08:35:46 EDT 2016
At Hay Creek We fired 3 kilns, 2 were soft brick and 1, a hard brick soda
We used Nils Lou designed burners fired with propane.
I don¹t know what pressure the gas was as there were no gauges, just went
by sound of the combustion at the burners.
If I¹d have to guess I¹d estimate between 3 and 5 lbs gas pressure.
We just opened the pet cock on the burner a little, lit them, then
increased gas pressure a turn or two
I seem to recall one chilly morning Mel taking one of the lit burners and
pointing it into the damper slot to warm the flue.
We mainly watched the pyrometer for heat rise and fiddled with the damper
wschran at cox.net
On 10/3/16, 9:07 PM, "Clayart on behalf of sumi"
<clayart-bounces at lists.clayartworld.com on behalf of sumi at herwheel.com>
>but my question is always, can you do this with atmospheric burners?
>Turn them on high immediately? In the past I found the kiln temperature
>simply didn't increase if I turned the heat up too high too fast and I
>have always assumed the kiln needs to build up draft gradually to pull
>enough air in to burn more gas.
>> pre heating your kiln to a rather high temp, like
>> 1200F over night does nothing for your kiln.
>> in fact, it destroys the insulating value of your brick.
>> if your kiln is hot on the outside after pre/heat then you have wasted
>> the thermal quality of the brick.
>> what i suggest is: use a strong pilot flame and bring your kiln up to
>> under 400F over night. (auto shut offs or baso valves are pretty
>> important if you do this.)
>> it will warm your shelves, melt the wax etc. and only the inside face
>> of your kiln is warm. the pots are now warm and ready for firing.
>> i turn my kiln to high right off the bat. as i fire, the pressure is
>> turned down. in fact i have almost no gas pressure at cone 11.
>> now you have the famous dance. gas pressure, back pressure, damper
>> settings for reduction and then
>> a down fire protocol for crystals and copper red.
>> each potter will figure out what works for them.
>> this system assures you a fine use of fuel, you fire faster without
>> harming your pots or kiln.
>> in many cases you will get a color or surface shift...and make sure
>> you chart what you do.
>> there are many potters that are using this system with great affect.
>> and, it does save fuel. and if you use blue flame and modest reduction
>> it is even better. color becomes more viable.
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