Lajos Kamocsay on mon 11 mar 02
Hello,
I've almost finished building my kiln this past weekend. It's a small =
downdraft, about 7 cu ft. I will use one 500k btu propane burner.
I'd like to fire it next weekend. I know that I have to preheat it, but =
I have no idea how to. I definitely don't want to fill it up with gas =
and blow it up...
Any suggestions?
Thanks,
Lajos
Bruce Girrell on mon 11 mar 02
Talk with Marc Ward (865)397-2914. Call him, don't e-mail him - he'll only
respond to your email with a note telling you to call him.
I use a small burner that I purchased from Ward Burners for my preheat. It
is the one shown on http://www.wardburner.com/venturi_raku.cfm as the
"piggyback pilot" burner. It probably has the output of about three
blowtorches. I let it run at about 3 PSI for about eight hours to preheat my
35 cu ft "stack o' bricks" kiln. Love that little thing. It's perfect for me
as a preheat burner.
BTW, your burner sounds as though it might be oversized for your kiln.
Taking the most pessimistic conditions from Marc's page shows that you'd
need about 150,000 BTU/hr - 1/3 of what you have - to hit cone 10 in about 8
hours. Better insulation and longer firing schedule would reduce that even
more.
I overbought also. I have two MR-100s to fire the stack o' bricks. I have to
keep them throttled way back. They never really get a chance to develop the
flame that they were designed for, which also means that they don't draw
sufficient primary or secondary air to burn efficiently. Do they work? Well,
yeah. Every bit of pottery that we have made has been fired with the
MR-100s. But I have trouble maintaining oxidation when I want it, I have
trouble maintaining even temperature, and I use more propane than I need to.
But I learned something about kilns in the mean time.
I hope your kiln turns out well.
Bruce Girrell
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