yodelyfish Posted April 4, 2019 Report Share Posted April 4, 2019 Hi All, I am posting here on behalf of a family member. She is a professional pot maker from MN and has been firing on a city natural gas line for the last 25 years. About 2 years ago she decided to move her operations out to a location close to home and has been working on a propane line ever since. Just last year she started firing for the first time and the results were not as good as she hoped. Certain glazes melted off the pots and some appeared to have simply fallen off (cured on the pot and then fell off in solid chunks). My question is: has anyone used natural gas and transitioned to propane and had these problems or does anyone have any suggestions when firing on propane? She uses a specific mix of clay she orders. I do not have access to the contents. Link to comment Share on other sites More sharing options...
Dick White Posted April 4, 2019 Report Share Posted April 4, 2019 Is she using the same kiln? Propane has more BTUs per volume of gas than natural gas, so the orifice for a natural gas burner is larger for the same amount of heat. If it is the same kiln but the orifices in the burners were not changed for propane usage, they are burning much hotter than before. Link to comment Share on other sites More sharing options...
Bill Kielb Posted April 4, 2019 Report Share Posted April 4, 2019 34 minutes ago, Dick White said: Is she using the same kiln? Propane has more BTUs per volume of gas than natural gas, so the orifice for a natural gas burner is larger for the same amount of heat. If it is the same kiln but the orifices in the burners were not changed for propane usage, they are burning much hotter than before. Dick is right Propane has considerably more BTU per cubic foot and often is used at a higher pressure. Hopefully the natural gas kiln was not simply relocated and hooked up to the propane. Firing kilns is all about rate of rise and final temperature at some controlled rate of rise as well as the cool down rate. Natural gas = approximately 1000 btu per cubic foot Propane = approximately 2500 btu per cubic foot without a decent understanding of this, her results are likely to be very random and unpredictable. Link to comment Share on other sites More sharing options...
Fred Sweet Posted April 4, 2019 Report Share Posted April 4, 2019 yodely- if you gave questions about the orifice size to use for the kiln, contact Ward Burner at http://www.wardburner.com/ Their contact information is at the bottom of the page. Helpful folks! Regards, Fred Link to comment Share on other sites More sharing options...
Mark C. Posted April 4, 2019 Report Share Posted April 4, 2019 As noted orvice size on burners needs to be changed. I'm not sure if this applies to your question but there is a difference in glaze appearance between the two fuels for example many glazes look completly different in one fuel vs the other My Otto Hino's Million dollar yellow for example does not turn yellow with natural gas but looks supoer yellow in propane. This is never disscusssed much but can be a huge issue. Link to comment Share on other sites More sharing options...
CactusPots Posted April 4, 2019 Report Share Posted April 4, 2019 It will most likely take a little trial and error to dial in the orifices to the perfect flame given the variables on site. They make a special set of by hand drill bits to slowly enlarge the orifice. Obviously starting with new jets. Link to comment Share on other sites More sharing options...
Mark C. Posted April 4, 2019 Report Share Posted April 4, 2019 Use number/letter drill set as there are more size variations it’s also the sizes they refer to in orfice sizes Link to comment Share on other sites More sharing options...
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