Just like the topic says

 

good sign of a leak get some soapy water and check everything had an issue a few years ago when I got a new machine and it turned out to be a new hose hooked to the regulator

 

Not a tig, but its pretty much the same I believe and no my pressure doesn't drop on my mig.

As ^ said. Probably have a leak. I ahve come back to mine weeks later and it still sitting with pressure in the lines.

 

Usually... I've had a couple bottle's over the last year that seem to "leak down" much slower (day or two vs. hour or two) so the leak must be in the bottle-regulator union.

Drives me crazy, but I've developed the habit of shutting the valve if I'm away from the torch for any length of time.