Joel OF Posted July 8, 2015 Share Posted July 8, 2015 (edited) Hi all, can anyone tell me what's going on here? I bought an oxy-propane kit t'other day (been shown how to use it safely by my fabricator workshop mate who also uses oxy-propane) but this confused both of us a bit...Why does my propane regulator have 2 different numbers for bar on it and why would the instructions suggest a pressure to a decimal point e.g 0.2 when that seems to have no relevance to the numbers on the bloomin' regulator? Hope my question makes sense. Edited July 8, 2015 by Joel OF Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted July 8, 2015 Share Posted July 8, 2015 I'm speculating here but believe 4 bar is the safe working limit of the secondary side and the 25 bar is the limit for the primary. In other words, your fuel tank pressure should not exceed 25 bar and you should not try to achieve more than 4 bar on the torch side.The decimal settings in the instructions are where you should set the torch pressure (and a side note is that you should never exceed about 1 bar for free acetylene) Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted July 8, 2015 Share Posted July 8, 2015 (edited) Well, mSter wouldridge may be right Edited July 8, 2015 by Charles R. Stevens Quote Link to comment Share on other sites More sharing options...
Glenn Posted July 8, 2015 Share Posted July 8, 2015 (edited) 1 bar = 14.503773773022 psi Edited July 8, 2015 by Glenn Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 8, 2015 Share Posted July 8, 2015 (edited) I've been using the AllStates oxy propane torch for probably 30 years now and love it. However All Sates doesn't seem to want to deal with torches anymore but eh patents have expired so Harris can sell the same set ups under their own name. Harris has been built eh All States torches since day one so they do know what they're doing.Anyway, the way a proper oxy propane torch operates isn't by regulating the propane pressure. It is preset, usually at the factory, hence the 25 bar x 4 bar label on your regulator. There shouldn't be ANY way to adjust the pressure on your regulator!A REAL oxy propane torch system's propane is METERED according to how much oxy is flowing, NOT prop pressure. 4 bar is a REALLY HIGH feed pressure through the reg.A designed/real torch operates in OZ per sq in. of propane as it's metered from there but it shouldn't be adjustable. I'd literally have to take my propane regulator apart to adjust it's pressure or flow rate.I don't know what you have but I'd assume it's a regulator for a torch conversion and not a proper oxy prop torch system.Don't take my word for any of this, contact the manufacturer and find out what's what. Then contact Harris and find out how a real oxy propane torch works. A real oxy propane torch is a joy to use and costs about 2% as much to operate in consumables. They're expensive up front but will pay for themselves 2x before you run through a 20lb. bottle of propane.Frosty The Lucky. Edited July 8, 2015 by Frosty Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted July 8, 2015 Share Posted July 8, 2015 I agree that 4 bar on the secondary side is very high but so is 25 bar on the primary side (at least for fuel gases)...the numbers may be failure points, i.e., a "not to exceed number". A big rosebud can pull a lot of fuel - maybe they want to make sure the user doesn't push the regulator to failure.I also agree that contacting the manufacturer is the correct way to know for sure... Quote Link to comment Share on other sites More sharing options...
timgunn1962 Posted July 8, 2015 Share Posted July 8, 2015 The higher value of 25 Bar is about 370 PSI and is the safe working pressure on the inlet side. Propane liquifies under pressure and the vapor pressure above the liquid depends on the temperature of the cylinder. Hotter cylinder, higher pressure. 25 bar/370 PSI is reached at about 145 degF.The lower value (4 Bar in this case, about 60 PSI) is the maximum range the outlet pressure can be set to on an adjustable regulator, or the fixed outlet pressure on a non-adjustable regulator. Quote Link to comment Share on other sites More sharing options...
Joel OF Posted July 9, 2015 Author Share Posted July 9, 2015 Cheers folks that all seems to make sense as there's numbers 1 - 4 on the side of the regulator which relate to how much you turn open/close it. Quote Link to comment Share on other sites More sharing options...
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