Close regulator to 0 when done welding?

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On my mig I use CO2 and set the flow to about 18-20 CFH.  When I'm done for the day I just close the valve on the cylinder and leave the regulator alone so it will  be set for the next time.  My question is should I be closing the regulator to O CFH each time I'm done welding for the day and then open the cylinder and re-open the regulator to  18-20 CFH the next day when I start welding?Thanks, Wayne
Reply:No need. Just close big valve and purge.
Reply:Thanks, from some posts I have read I got the idea you might damage regulator by opening  the cylinder on it while the regulator was already open.
Reply:The other opinion is to back off the flow valve to zero.  Reason being that the spring would weaken over time under constant tension and yield inaccurate flow rate...  I really don't think its an issue honestly.. I have never disassembled a regulator but I thought the spring just keeps the knob tensioned and its a check ball or pin that opens a certain amount to let the gas flow thus the spring is not directly controlling the flow but I could be wrongTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Yes, the spring pushes on a valve to control flow. The spring won't weaken (or a amount that anyone would notice).We have regulators on trucks that are outside 24/7/365 and are never ever changed. The gauges will rot out and ruin the regulator after 10-20 years but the valve system is always fine. Very simple design really.And FYI, I open the big valve slowly. I don't just crack it wide open. However on the trucks I always "just open them up" because we are always in a hurry.
Reply:An old Linde book recommends backing them out to zero.  If they are not to be used for awhile, turn them in ever so slightly to relieve pressure on the valve seat."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Three parts to a regulator, loading (spring), measuring (diaphragm), and restricting (orifice and seat). If the spring weakens over time then it just requires that you turn the screw in a wee bit more to compensate. Crappiest part of these tiny regs is the gauge. I turn my tank valve off and leave it be. I have some of these small regs at almost 15 years old and still running fine.
Reply:Here's a cutaway view of a single-stage regulator. Attached Images"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I will tell you what I was taught.Something like a compressor, not such a big deal if you drain the tank the pressure builds slowly.On a tank (Co2, argon, whatever) even to open it slowly you get a bust of pressure.  That pressure hits a rubber diaphram in the regulator.  This can cause it to rupture and put full pressure to the line.Can't say I have heard of it happening, but don't see why it's not possible and it make sense to me.I shut the regulator off on my welder every time I use it.  I also pull the regulator off the bottle and cap the bottle, but then I don't weld for work either.Me I would shut the regultor off (set to 0)Just me, part of it being taught what I would like to think correctly, and seen alot of people take an Oxy Accet setup for granted.  I am actually suprised I have not seen an explosion yet.
Reply:nope...BobBob WrightSalem, Ohio  Birthplace of the Silver & Deming Drillhttp://groups.yahoo.com/group/southbend10k/http://groups.yahoo.com/group/sawking/1999 Miller MM185 w/ Miller 185 Spoolmate spoolgun
Reply:I've had the same regulator on my mig bottle since 05, and I've never backed it off to zero when done welding.  I just shut the machine off, close the valve, and move to something else.-AaronJet 17.5" Drill Press1942 South Bend 16x84 Lathe1980s Miller 320A / BP --- 2013 Power Mig 2562012 Jet 7x12 Horizontal BandsawVictor O/A Setup