Question about regs unscrewing from HPA tanks

[ScatterPlot]

I just got a used Armageddon in the mail today, and after a while of messing with it (not like tinkering, just moving it around on the gun, etc.)I tried to inscrew the Arm from the reg as I had done a few minutes ago. Well, it was pretty hard, and then all the sudden the tank starts unscrewing from the arm. I've had a Crosfire preset for a while but never had this problem. My question is...
what do I do to SAFELY get the arm back on again? I did a search and all that I can find is that I don't want to use any type of Loctite, Teflon, glue(duh), etc. on it, but there has been some debate on whether hand-tightening the valve was enough. So, should I get it put on by a shop or something, or just tighten by hand? If I get a shop to do it, where should I go? Scuba store? Hydro-test place? If I do it by hand, how should I do it? Hold it in my legs and use my hands, or use a vice for the reg and screw in the tank part with my hands? One last thing, that is, if you tell me to use a vice that would hold the tank, how should I do that? Wouldn't the vice part that grips the tank mess up the windings and all? I generally thought that was a bad thing to do. Well, thanks in advance, any help is greatly appreciated.

[ScatterPlot]

Nobody knows this? Come on, this is AO!

[ScatterPlot]

Bump

[Aegis]

I'll take a guess at the reason for few replies - many of us are comfortable working on mags or even regulators and offering advice for the same, but dealing with the high pressure side of an air tank is getting into airsmith territory. You really should contact Air America and do whatever they suggest.

One word of advice is that the arm will easily come off the reg when empty, but if it is aired up you will play hell to get it off and REALLY suffer trying to get it back on. And once it is off, you can't dump the air until is IS back on. Potential issue there.

[ScatterPlot]

Thanks for the reply, but where mine is unscrewing is from the arm to the tank itself. I'm not sure how I make sure that it's on securely or not.

[Aegis]

I guess my point was a bit vague - I know you are talking about the tank itself. That is airsmith or factory territory in my opinion. The bit about the arm unscrewing from the reg was just for info.

[ScatterPlot]

Oh, ok thanks. I'll talk to some locals about it and figure it out from there. Can Scuba stores do this kind of thing?