Changing oxygen low pressure gauge

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I did a serch first..... I want to buy a NEW low pressure oxygen gauge so I have an easier time with using my Dillon mkIII and my Purox w200 which requires 5psi fo 98% of any welding/brazing I might do. The Dillon requires 4psi.  I was going to check out what my LWS (airgas) has to offer. IF they have a gauge that I can put on my Harris 2 stage regulator, do you think there will be a problem changing it myself? I understand and know how to wrap the teflon tape. I also understand the issues with and oils from my hand and contaminates. My work area is clean and I am somewhat confident. Just need to know if this is safe to do on the low pressure side or not. Should this be left for the pro's?
Reply:If you can get the old gauge off without any problem, and if you don't contaminate anything in the process of putting the new one on, then it's perfectly safe. Check the new one before installing though, just as one should check the barrel of a firearm taken out of storage before firing it. Just 'cause it's "new" doesn't mean something like particles of paper couldn't have gotten inside it.I assume you want to put on a gauge with a lower reading, particularly one which indicates more precisely at the bottom end. Generally, a gauge should only be used to about half its upper reading, otherwise the Bourdon tube material can work harden or stretch and the gauge loose its accuracy.
Reply:I did this on my OA setup.  I replaced a 200PSI max gauge on the oxygen with a 60PSI gauge.  My LWS had gauges in sealed bags that were guaranteed oxygen clean.
Reply:You should be fine as long as you take reasonable care. Be cautious that you don't wrap the tef tape too far down and get little pieces in the gauge opening..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSW Be cautious that you don't wrap the tef tape too far down and get little pieces in the gauge opening.
Reply:[QUOTE=Gerry1964;1865271]Great advice, and remember just a couple of wraps round and bed it into the thread with your nail, before winding it back in, That way your guaranteed to get the seal all the way in.I've seen too many people wrap the tape about 10 times round, its far too much and all that happens is it gets pushed out as the part gets threaded in, Defeats the object[/QUOTThanks for the replys guy. I'm a plumber by trade. Yes, I wrap the p!ss out of threads and I'll make sure I follow the advise given.
Reply:If you want the technicality of the thing then no you are not supposed to use regular teflon tape on oxygen fittings. There is a special oil free green colored teflon tape for oxygen fittings. 1/4" brass threads will seal just fine without them. The danger with white tape is that it may contain oil. Oil, Oxygen and heat of compression are normally good things inside a diesel engine, but not in an oxygen gauge. It has been done plenty of times, and seems to work just fine, but make your own informed decision.
Reply:Some guages come painted with dope or taped appropriately.
Reply:The issue in the title of this thread has been pretty well covered.  Chances are your Harris dual stage regulator was designed so it could be used with their vvc series divergent bore cutting nozzles(machine cutting).  Changing out the guage won't really make using the two torches you mention for oxy acetylene steel welding or or other single flame applications any easier.  Changing out the internals for those of the lowest delivery pressure option for that regualtor series in my opinion will.  This kind of stuff has been covered on here in other threads indipendent of my personal logic.  I can't say about the Dillon, the pruox 200 has smaller hoses generally so the lag between knob re adjustment and final equalization of flow rate will be a bit less which is kind of the frustration with small single flame stuff.  There have been threads on here as how to adjust without even looking at the guages, again not sure if the dillon is really different.  Even if you get say a 40 psi max guage you may still find the blow the gas against the cheek technique is better.fran
Reply:Originally Posted by walkerIf you want the technicality of the thing then no you are not supposed to use regular teflon tape on oxygen fittings. There is a special oil free green colored teflon tape for oxygen fittings. 1/4" brass threads will seal just fine without them. The danger with white tape is that it may contain oil. Oil, Oxygen and heat of compression are normally good things inside a diesel engine, but not in an oxygen gauge. It has been done plenty of times, and seems to work just fine, but make your own informed decision.
Reply:Originally Posted by fran...k.The issue in the title of this thread has been pretty well covered.  Chances are your Harris dual stage regulator was designed so it could be used with their vvc series divergent bore cutting nozzles(machine cutting).  Changing out the guage won't really make using the two torches you mention for oxy acetylene steel welding or or other single flame applications any easier.  Changing out the internals for those of the lowest delivery pressure option for that regualtor series in my opinion will.  This kind of stuff has been covered on here in other threads indipendent of my personal logic.  I can't say about the Dillon, the pruox 200 has smaller hoses generally so the lag between knob re adjustment and final equalization of flow rate will be a bit less which is kind of the frustration with small single flame stuff.  There have been threads on here as how to adjust without even looking at the guages, again not sure if the dillon is really different.  Even if you get say a 40 psi max guage you may still find the blow the gas against the cheek technique is better.fran