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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText>Dear Peter<o:p></o:p></p><p class=MsoPlainText>>I can't follow Andy's figures for the stoichiometric volumes.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='color:black'>Agreed. He says several things that are suspect.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText>>C2H2 + 2.5 O2 = 2CO2 + H2O eg 2.5 volumes oxygen for 1 volume of acetylene<o:p></o:p></p><p class=MsoPlainText>>C3H8 + 5 O2 = 3 CO2 + 4 H2O eg 5 volumes of oxygen for 1 volume of propane<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='color:black'>Agreed.</span><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>In use, propane for cutting has to be held for longer on the surface preheating and the gap is more critical during the cut. It is because of the high gas velocity entraining air (cooling). Restarting a cut that for some reason was stopped requires far more preheating and tends to be messier and the O2 central port needs to be opened more gradually to give the iron time to ignite.<o:p></o:p></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>There is a way to make your own cutting torch using iron wire as the fuel! The only gas is Oxygen. They used to use it in the 1920's. It is the appropriate technology way to cut two a inch plate without gas! In the US I think they would call it a Redneck Cutting Torch. <i>Rooineke gassnyspruitstuk</i> in Suid Afrika. Ja. Maybe you would say <i>rodenek snijbrander</i>.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Regards<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>Crispin<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>™</span><span style='color:black'><o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p></div></body></html>