You are correct the thread on this was very confusing. While my dad
has for years left his gauges (30 to 40 years) as set on his torch
set and he leaves them in an open shed all year round, he has never
had a problem with them. I, on the other hand, have always followed
the instruction that came with my torch set, and have never had a
problem with mine. This just gives you some background on my usage.
Single gauge torch-I know nothing of these, I have seen them but
that is all, do not take anything I am about to say as applying to
your single gauge torch setup except the 15 PSI maximum on Acetylene
You do not turn the Acetylene valve fully on, it was recommended by
the manufacture of my gauge set and that was how I was taught in
welding class, once you see pressure on the main gauge you give it
one full turn, then adjust pressure on the secondary (low pressure)
gauge. For bigger things, you only open the valve enough to allow the
flow required by the tip you are using. Jewelry tips do not require
that much flow so a full turn should be enough I know you don't have
an oxygen bottle, but if you did, the oxygen is turned fully on in my
instructions and training, and then adjust the secondary for the
pressure recommended for what you are doing.
I am surprised your gauge set did not come with recommended pressure
settings mine did, but it is not an Air/Acet. torch set. What I will
say as a general and most important rule, never set your Acetylene
gauge over 15 PSI.
I was taught to relieve the pressure on the gauges and drain the
lines after use. Draining the lines is the only point my dad and I
have in common on torch use.
This may or may not clear things up for you, I hope it does. If not,
it is safe guidelines to follow as stated in my welding class and by
my gauge set manufacturer.