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Stewart

Member Since 17 Dec 2010
Offline Last Active Sep 21 2013 07:01 PM
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Posts I've Made

In Topic: Mini Soda Kiln

04 September 2012 - 02:19 PM

Thank you very much!

Stewart

One way to help slow down freezing propane tanks is to have them plumbed to work two tanks in tandem for one burner. I have used this system for
over ten years for firing raku at workshops and on my one kilns. Also make sure you have a regulator on the tank and a burner with the right BTU output.
Otherwise you could either wait for days trying hit hit temperature or you could send too much propane out the chimney.
For a soft brick well insulated kiln you need about 30,000 btu's /hour per cubic foot at ^10.

Marcia


In Topic: Mini Soda Kiln

04 September 2012 - 02:18 PM

Thank you very much for your input. Would you suggest the burner port on and the chimney on the same side of the kiln?

Thanks,
Stewart


I don't know about the physical requirements for natural gas at normal house pressures, but
with propane (a barbecue tank) and a venturi (mk750 or similar small sized plain venturi),
a burner port is a hole cut into it [the side] and the chimney is a hole cut in the top. I run
mine as an updraft and have no problem controlling reduction. Although I don't
use any sort of oxygen monitor, I feel like I get oxidation when I need it, and
reduction is of course easy to get in a fuel kiln.

Adjusting the damper does more than affect the conditions for your glazes, it also
helps you use your fuel effectively.

Many people recommend placing a shelf inside the kiln just below the 'chimney'
hole to reflect heat back in, but I like to instead entirely cover the hole with part of a kiln shelf
supported on 1 inch posts around the kiln. I 'adjust the damper' by leaning firebricks
on it to partially block the effective opening. It's easy and works well to keep the top from
cooling too quickly. And you don't need to plan for extra posts on your top ware
shelf. As an added bonus, you have a number of warm bricks that
can be used to warm a water bath to keep the propane tank from chilling down too fast if you
are running the regulator at high pressure from a single 5 gallon tank.

I run my venturi up to 6psi (which I think is much higher than natural gas pressure)
and it is able to draw quite a lot of air.

You would probably be able to fire 4 cu ft to cone 10 on a single tank, but if you
go this route, I'd have a backup tank just in case.

A disadvantage of the propane torch setup I use is that the flame enters from the
side at the bottom and the first shelf is 4 - 5 inches above the kiln floor. Of course,
for a soda kiln, you can use this space to load your soda (I do this).

I am following Mark's (and others') advice to coat my brick to protect it, (colloidal
silica/zircon or ITC) but Laguna has been slow to fill my order for zircon recently
so I don't have direct experience with this.

I think you'll have a great time if you try it.

warmly,
Lily


In Topic: Mini Soda Kiln

03 September 2012 - 09:47 AM

The kiln is about 4 cubic feet and I was planning on using gas.