Acetylene reg on a 20lb propane tank,wont fit???Help please

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My smith acetylene regulator will not fit my 20 propane tank.  I was hoping to get out of renting a acetylene tank...Who makes a regulator that fits those threads????Last edited by KYBOY; 09-12-2007 at 08:28 PM.
Reply:One of the newer OPD valves??
Reply:The valve on the 20lb tank is an OPD valve. the tank was givin to me so I didnt know it had  a OPD valve befor I got it.Last edited by KYBOY; 09-12-2007 at 08:56 PM.
Reply:The left hand threads are still inside the valve.  Your regulator fitting may not be long enough to reach them.  If you have a RH thread regulator, an adapter is available for $5.00DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Well the older standard fittings should work, some might not. All of mine do. They brought in the new OPD's in in phases. The latest phase right now is the coarse outside thread, the standard inside thread BUT there's a rubber seating face which is spring loaded in a forward position which acts as a check valve for secondary protection. On these it may seem as tho the threaded nut doesn't want to go in but it's a matter of some light force to start detenting that spring. They no longer just run in the come up tight all at once in those. Carefull not to overtighten as you could smash that rubberized face. There were several variants of this in the ealier versions, all similar. SOme had more of an 'O' ring seal instead of a full face rubber. All can be problematic. There can be a "turn on" sequence issue for some of the high volume devices also. Cutting torch should be fine.
Reply:Mine has the Large course outside thread with the inner rubber O-ring like you desribed Sandy...