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reduction firing and balancing those burners

updated mon 13 jul 98

 

rcarlton@valylink.net.au on mon 6 jul 98

Hi all...I am raising the question of reduction firing once again

I have a 65cuft gasfired brick kiln with 6 burners 3 a side. I am having
problems getting them to fire evenly. the temperature seems to be ok
throughout most of the kiln. one of my glazes is very sensitive to
reduction and getting the burners to reduce evenly through out the setting
seems to be problematic.
Has any body got a sure fire method of balancing those burners..it was i
think mel jacobson who said to cut small holes in the kiln above each
burner so the reduction can be observed from each burner. Before I do that
I thought I might call for any other ideas from the group

thanks for your help


cheers :) Ray Carlton

McMahons Creek Victoria Australia



gwalker on tue 7 jul 98

Ray,

We have this problem too. I can have, say, 5 pots on a shelf, and one
will be perfect while the others are ghastly. We use our reduction kiln
(it is about 120 cubic feet) mostly for copper reds. One shelf will
produce superb colours, and the ones above, below or beside will be
disastrous.

This Thursday I am pulling the entire stacks out, clearing out the flue
channel and will try re-stacking with more of an air flow in the channel
in the hope that this will remedy the situation. I will also re-install
the a new set of burner ports and re-align them in the hope that this
will restore the evenness we once had in this kiln. It is a nightmare
beast! Started playing up badly (although it has never been 100%) when I
re-fibred the seals and re-fibred the stack-binded roof a few months
ago.

Will keep you posted after another gloss firing early next week.

Good luck with yours.

Geoff.

Ron Roy on sun 12 jul 98

Hi Ray,

I solved this problem many years ago. How to tune each burner so that they
are burning with the same amount of fuel and air. I have 4 burners two on
each side - atmospheric with burner blocks and gates to regulate secondary
air and screw in flanges? at the cold end of each burner ( primary air
adjustment.)

I drilled 1" holes about 3/4 the way up over each burner. This way I can
watch the flame after making adjustments to either air or gas and make all
four flames look the same. I never use the primary air adjustment. I have a
24 cu ft. stacking - natural gas soft brick kiln and a huge 12" inside
dia., 30 ft high chimmney.

I'm on my 750 firing and can't remember when I last has a flash.

I'm off again tomorrow for another week teaching my glaze course at Canador
college - if you have more questions I will return Friday, July 17.

>----------------------------Original message----------------------------
>I have a 65cuft gasfired brick kiln with 6 burners 3 a side. I am having
>problems getting them to fire evenly. the temperature seems to be ok
>throughout most of the kiln. one of my glazes is very sensitive to
>reduction and getting the burners to reduce evenly through out the setting
>seems to be problematic.
>Has any body got a sure fire method of balancing those burners..it was i
>think mel jacobson who said to cut small holes in the kiln above each
>burner so the reduction can be observed from each burner. Before I do that
>I thought I might call for any other ideas from the group
>Ray Carlton

Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849

Web page: http://digitalfire.com/education/people/ronroy.htm