In CA compressed air tanks are required to undergo periodic inspection. The
inspector scraped a little paint off the tank, attached a small magnetic
sensor to the tank and took a reading. He said in the old days they had to
pull the inspection plugs, and use large, very expensive micrometers to
measure the wall thickness.

You may also consider hydro testing. They fill your tank with water and if
it will hold 600 PSI they will certify it for 300PSI.

They use water so if the tank ruptures the pressure drops to zero before the
shrapnel starts flying. The local welding supply place might be able to do
this for you.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.
"Ignoramus29516" wrote in message
...
I bought a 5 HP, 3 phase, 100 gallon Atlas Copco 3 phase compressor
today. That could be for just resale or single phase repower and
resale. The motor is 184T frame. I am concerned that, as I opened the
drain, quite a bit of water drained, about 2 quarts. I am considering
opening up the big inspection holes and just peeking in there to see
how bad is the rust.

The story of this compressor is that it was used at an auto shop, then
the owner died, and it sat in the widow's garage for a while. That's
what I was told anyway. The compresor runs fine, but I am concerned
about the tank's integrity. I did not run it above 50 psi.

Some more data. The compressor head is rated for 300 PSI (!). It is a
bad ass head, very complicated. The tank is rated for 200 PSI. The
emergency popoff valve is rated for 175 PSI.

Air connections to the pressure control relay are complicated and one
line's plastic fitting is broken. (hopefully no big deal that can be
fixed with copper line).

So, again, is it sane to try to open up the inspection hole? I tried
doing it today and it just would not budge. I could make some
makeshift tool, but perhaps there is something simple that I am
missing. I need a square socket that would go into the hole on the
plug.

i