Gas cylinder threads - problem solved

dickm · 26 Jun 2013

I'm confused :? . Some years back, my Mig ran on Argoshield, until the BOC bloodsuckers had me drained dry. Then got hold of pub-type CO2 cylinder, but then my refill source disappeared. So.o.o..., finally hardened heart and got a Hobbygas Argoshield equivalent. Went to fit it, and my gauge (marked "argon") wouldn't fit. The cylinder has LH thread, my gauge is RH. Yet I'm sure this is the gauge I used on both the BOC and pub cylinders.
Or is this another sign of advancing years????

graduate_owner · 26 Jun 2013

I've no experience of Argoshield etc, but I believe that left hand threads are normally used for fuel gases such as acetylene and LPG. That way you can't get gases such as oxygen connected to acetylene by mistake. This does not explain your issue though, nor does it explain why Hobbygas use a left hand thread for a non-fuel gas cylinder. (Unless perhaps they have acquired a quantity of fuel cylinders and are reusing them for their Argoshield - reusing cylinders could help them keep costs down)

K

No skills · 26 Jun 2013

I 'picked up' the wrong bottle of gas at work the other week, didn't realise it until I had lifted it onto the welder and went to fit the regulator and found it to be the wrong hand thread #-o #-o #-o #-o #-o

Turned out it was a gas mix for aluminium and not the regular c02/argo mix we use - which is currently 'Coogar' - which still doesn't seem to last as long as the same sized argoshield bottles from boc (there are no leaks!).

FWIW

Spindle · 27 Jun 2013

Hi Dick

I have both BOC Argoshield and pub CO2 in the garage at the moment and can assure your sanity

- both are RH thread.

Regards Mick

Hitch · 27 Jun 2013

BOC, and air products use the same threads....right hand female on the cylinder for welding gases (230bar fill cylinders) such as Argoshield, Stainshield, Coogar, Astec...

Air products also offer NEVOC cylinders, which re filled to 300bar, these are Ferromax, Inomaxx, Alumaxx... These have right handed, but male threads on the cylinders. A special regulator is needed to cope with the additional pressure, so different threads prevent a normal regulator being used.

I cant say i have ever come across a welding related (non fuel) gas cylinder with a left hand thread. That said.... there is a few gas mixtures that contain Hydrogen, such as Hytec and Protec (might be prodarc!) I imagine these may well have a LH thread, but are fairly specialist gases. This will probably account for No Skills's problem

Pub CO2 has a male cylinder thread i believe, but also right hand.

As for hobby gas, not sure whats going on there, id be inclined to ring them and find out.

dickm · 27 Jun 2013

Red face department - I was being totally stupid. Not sure what happened when I tried to screw in the regulator yesterday, but (even with my glasses on) I was convinced it was the "wrong" thread. Then tried again this morning, and it fitted like a glove.

It's definitely age...............................

But at least folk have confirmed the basic rule that combustible gases are LH and shielding gases RH thread, which may help someone else