Welding Tips and Tricks

So i have an old torch and when i turn the lower oxy knob on it already pisses oxy from the tip before i even open the upper knob. What would the problem be? I unscrewed the lower knob and it had some kind of sticky teflon strip or something wrapped around it not sure if i should taken it off but i did thinking maybe that was the problem and i just needed to rewrap it with whatever the stuff is.

The thin teflon is packing that keeps the valve from leaking around the threads. If your leaking only when you turn on the lower knob of a cutting head but not when you shut it off, then you problem is the upper knob not shutting off.

Edit: it’s also possible you have the wrong upper head attached to your handle.