Acetylene vs. MAPP vs Propylene fuel gasses

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So I've used acetylene, MAPP, and now I've seen Propylene tanks recently too.Do each of these fuel gasses need their own tips and regulators?  OR can they all be used with Acetylene hardware?  What about grade R hose?I'd like someone who knows to confirm for me that one big advantage to MAPP and Propylene is that they don't have the withdrawl rate limits that tanks of acetylene do...I'm thinking of switching to MAPP or Propylene because then I can run as big a rosebud as I need to off of any size tank.But I may stick with acetylene if I have to replace all my torch tips and hoses.Thanks.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I' ve only used propane and acetylene so my experience is somewhat limited. As far as  hosed go though, I am almost positive that you would have to use grade T hose. Tips for acetylene won't work for other gases. It seems like Victor has a specific tip for each gas while Oxweld has fuel gas tips that work for any fuel other than actylene. What torch do you plan on using?IAMAW Local 330Airco 300 AC/DC HeliwelderAirco Dip-Pak 200 with Profax spool gunPowr-Kraft AC225Everlast PowerArc 200stBuffalo Forge No.21 drill pressSpeedglas 9100xxAirco, Oxweld, Purox, Victor torchesLincoln Ranger 8
Reply:Tips and hoses are cheap to replace.    Hoses should be replaced as they age anyways...I think acetylene is the only gas with a true limitation on withdraw rate.  Liquid tanks, like propane and CO2, have some withdraw limitation due to freezing.  I don't know anything about MAPP or propylene.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:With propane and other gasses subject to tanks freezing with high withdrawal rates, all you need to do is put the propane tank in a pan of water, that will keep the fluid in the tank somewhere around freezing, which is usually enough to allow higher withdrawal rates.This is what I do with my propane forge, whenever I see a pressure drop or frost on the tank, always solves the problem.No, this does not apply to the acetylene limitation on withdrawal rates.RichardSculptures in copper and other metalshttp://www.fergusonsculpture.comSyncrowave 200 Millermatic 211Readywelder spoolgunHypertherm 600 plasma cutterThermal Arc GMS300 Victor OA torchHomemade Blacksmith propane forge
Reply:Hoses:Grade R or RM is for acetylene only.All other fuel gases (petroleum based fuels) need Grade T hoses, which can also be used with acetylene.Withdrawal rates:Only acetylene cylinders have a safety-related withdrawal rate limit of 1:7 of the cylinder size in ft3/hr.Other fuel gas cylinders may have a practical withdrawal rate limit based on cooling of the cylinder or regulator flow rates, but that is not a safety-related limit.  They may require manifold systems or fuel vaporizer systems, but that is a flow rate issue, not a cylinder flow rate safety issue.The 'trick' of sticking a propane cylinder in a container of water works to keep the gas flowing.  But not at cold ambient temperatures.    Winter cold temperatures (say a moderate 20F), and a bucket of water (even hot water to start with) and a BIG heating tip (say a nominal 500K BTU/hr 'weedburner' torch)  and a 20 lb (which is actually now only 16 lbs of propane due to the OPD crap, grrr) propane tank while trying to melt some ice off the sidewalk and driveway can turn the water into ice PDQ.Also watch out for a floating/bobbing cylinder that may tip or knock something else over.Tips:Check your torch manufacturer's catalog/literature.  Most of the ones I've seen list acetylene tips and then there are other fuel tips.  So yes, you would have to replace the torch tips with the appropriate tip.  Victor has acetylene or propylene or propane/nat-gas tips listed.Heating value:Acetylene has the highest neutral flame temp of any of the common oxy-fuel combinations, so it is usually the 'best' for welding.  Several other oxy-fuel combinations come close, some are markedly lower in neutral flame temp.But some of the other oxy-fuel combinations do beat oxy-acetylene in total heat output on either a Btu/ft3 or Btu/lb basis.  On a gross Btu/ft3 rating (ignores the heat of vaporization of the fuel), pure butane 'wins'.acetylene = 1470butane = 3374natural gas = 1000propane = 2458MAPP = 2406methane = 1000propylene = 2371(values may vary depending on exactly what is in the cylinder. as 'propane' is usually not pure propane, but a slight mix of propane and butane and maybe methane).  The best laid schemes ... Gang oft agley ...
Reply:A thing to keep in mind, is that the reason acetylene is used in welding is not temperature alone, its the shielding effect of the secondary combustion envelope. This is actually of greater importance, and what makes other fuel gasses worthless for welding steels, stainless, cast iron, and the like. Brazing and welding of aluminum and some other alloys can be done with other fuel gasses.
Reply:MAPP gas is nearly impossible to find today.  MAPP Gas manufacturers have phased it out in favor of Propylene because some of the gases used to produce MAPP have found greater value in plastics manufacture.  Propylene does not have the withdrawal rate issues such as Acetylene because it is not dissolved in a liquid to stabilize it.   Talk with your LWS technical staff about availability and what recommendations they can offer.  Most will have some printed literature to help guide you.-MondoMember, AWSLincoln ProMIG 140Lincoln AC TombstoneCraftsman Lathe 12 x 24 c1935Atlas MFC Horizontal MillCraftsman Commercial Lathe 12 x 36 c1970- - - I'll just keep on keepin' on.