[Kitleyash]

I've converted an older Skutt electric kiln - inside size 17" w x 22" h for raku firing...cut a 3-1/2" hole for a burner port in the 6" ring which I've placed as the first ring and a 3-1/2" hole in the top for a vent. The burner is a GACO 75,000 btu hooked up to a small propane tank.

When I fired it off this weekend I got stuck on 1,650 degrees farenheit despite goofing with closing and opening vents and changing the air into the burner itself. I'd like to go a bit higher for the raku and wondered what was going on to keep the temperature from going any higher? The results for the ware that was in there was fine but I may want to use a glaze with a higher heat requirement

Help if you can...thanks

[Mudlark]

Kitleyash, on 27 April 2010 - 06:11 AM, said:

I've converted an older Skutt electric kiln - inside size 17" w x 22" h for raku firing...cut a 3-1/2" hole for a burner port in the 6" ring which I've placed as the first ring and a 3-1/2" hole in the top for a vent. The burner is a GACO 75,000 btu hooked up to a small propane tank.

When I fired it off this weekend I got stuck on 1,650 degrees farenheit despite goofing with closing and opening vents and changing the air into the burner itself. I'd like to go a bit higher for the raku and wondered what was going on to keep the temperature from going any higher? The results for the ware that was in there was fine but I may want to use a glaze with a higher heat requirement

Help if you can...thanks

It sounds as if you are reducing heavily which can happen if you run a burner straight off the gas tank when a regulator is needed. Most burners run at a pressure much lower than that straight from the gas tank.Propane tank pressure can range from under 10 psi to over 200 psi whereas burners operate at pressures measured from inches of water upwards to 20psi.You need to check the burner manufacturers recommended working pressure and regulate your tank supply to suit.
Hope this helps,
Mudlark

[kennwitt]

your probally using too small of a gas tank the 5gal for grills tend to freeze up from the fast release of fuel a 10 gallon will work but to check. see if this is the problem when you reach the tempature where it stops increasing look at your little tank and feel it or better yet run water over it with a garden hose and see if you system starts to increase again. Kenn

[Kitleyash]

Mudlark, on 01 May 2010 - 09:27 AM, said:

Kitleyash, on 27 April 2010 - 06:11 AM, said:

I've converted an older Skutt electric kiln - inside size 17" w x 22" h for raku firing...cut a 3-1/2" hole for a burner port in the 6" ring which I've placed as the first ring and a 3-1/2" hole in the top for a vent. The burner is a GACO 75,000 btu hooked up to a small propane tank.

When I fired it off this weekend I got stuck on 1,650 degrees farenheit despite goofing with closing and opening vents and changing the air into the burner itself. I'd like to go a bit higher for the raku and wondered what was going on to keep the temperature from going any higher? The results for the ware that was in there was fine but I may want to use a glaze with a higher heat requirement

Help if you can...thanks

It sounds as if you are reducing heavily which can happen if you run a burner straight off the gas tank when a regulator is needed. Most burners run at a pressure much lower than that straight from the gas tank.Propane tank pressure can range from under 10 psi to over 200 psi whereas burners operate at pressures measured from inches of water upwards to 20psi.You need to check the burner manufacturers recommended working pressure and regulate your tank supply to suit.
Hope this helps,
Mudlark

Burner, hose, and regulator all from a ceramics supplier that specializes in raku kiln firing so I should be OK there...thanks for the resposne

[Kitleyash]

kennwitt, on 02 May 2010 - 05:46 PM, said:

your probally using too small of a gas tank the 5gal for grills tend to freeze up from the fast release of fuel a 10 gallon will work but to check. see if this is the problem when you reach the tempature where it stops increasing look at your little tank and feel it or better yet run water over it with a garden hose and see if you system starts to increase again. Kenn

You are correct, I am using the small BBQ tank but was watching for freezing and running a hose over periodically...thanks