I am in the process of building a small furnace aimed at technical ceramics work, and I would like to use a carbon crucible. The carbon crucible's limit temperature is ~ 430 C in an oxidizing atmosphere and ~ 2800 C in a neutral atmosphere. My plans are to have the furnace vent to atmosphere so that it will not be under a vacuum. I intend to use bottled O2 to supply oxygen to the burner. If I adjust the mixture of fuel gas and oxygen so that the flame itself burns neutral, will this be enough to reduce degradation of the carbon crucible to the point where the crucible will survive temperatures in excess of 430C or will O2 from the atmosphere result in severe degradation of the crucible? Also, I am in search of a fuel gas. My first thought is Acetylene; however, I understand that Praxair makes a gas called "http://www.praxair.com/praxair.nsf/0/3C9FBEECABD517C6852570610002D0C4/$file/P-10116.pdf" [Broken]" which claims a slightly higher temperature than acetylene when combined with O2. As well, Starflame C is supposed to produce considerably less soot and be more stable than acetylene. Does anyone have experience with this gas? What other fuel gases might be suitable for the application? Thanks in advance for your help.