torch connections..how tight??

I sometimes run into this with oxy-acet and also argon. I wrap 3 or 4 wraps of teflon tape and re-tighten and that usually takes care of it.

Tight enough IS when there is insignificant leakage. Remember, the volume of gas trapped between the valve on the tank and the regulator inlet is very small. Leaks that you can't detect with soap will drop the gauge in a few minutes to an hour, but typical would be, say,

Also note that if you are shutting down for any length of time, drain the lines a back the regulators off. This increases the life of the regulator and the gauges, as well as providing insurance that an accidentally damged hose won't leak the trapped gas. It also lets you know if the tank valve is leaking, as the gauge will creep up. The valves, especially on rental tanks, tend to get wonky seats and leak.

Now, to your leak:

I presume you have CGA fittings- the taper set makes the seal, NOT THE THREADS, so DO NOT use lubricant or sealant. You probably already know this, but might as well cover this one now.

One thing to try: as you snug the nut, before it is tight, gently wiggle the regulator on the fitting. This will insure that the seat is properly lined up. The wiggle is a rotation around the axis of the fitting. Don't force it or try to move it if the nut is tight enough to make this difficult, or you can gall the seat.

Other places that you could be losing gas, and this is normal, are the stem packing on the valve (which is way on oxy and inert gas tanks the valve sould be opened fully in use-- there is a second seat on top to seal the stem) and through the regulator (they all have a range around which they regulate, and some types will bleed slightly until the outlet side pressure rises slightly above the nominal set point)

. (14 lines deleted) .

That would be OK for a normal pipe thread but since most connections in the line from tank to tip (excluding where the nipples connect to the regulator) are a metal to metal angular seal (can't remember the technical name but similar to 37 degree flare) you would probably not have much luck with the teflon tape on these.

Shawn

I use the teflon on the threads not any sealing connection. And I have had success with no notable loss of the contents.

it is a good idea to check the inside of the tank fitting for burrs and damage , I am not sure how they get there but it is a pretty common occurrence, we use a small cratex wheel at work to remove them when we find them , also the fitting that goes from the tank to the regulator has two ends , make sure it is secure in the regulator as well ,Teflon tape is good for this as well