On Wed, 26 Sep 2007 08:37:25 -0500, Ignoramus25760
wrote:

I saw something strange on Monday. A big horizontal compressor tank,
with nice old blue paint on it. It is a 25 HP reciprocating Dresser
LeRoi compressor written off by Fermilab, surplused as "scrap". It is
not even a compressor, it is a head separate from the tank as a pile
of garbage.

It is probably rather broken, though I have no way of knowing. It is
also huge.

Here's my question.

The horizontal 120 gallon tank has feet welded to it, looks like stick
welded out of position. The welds are not painted at all, and clearly
have this blue paint burned around the welds. So they welded the feet
on themselves, not too long ago.

I thought that you are not allowed to weld stuff to tanks like this?
That welding stuff to air tanks could lead to some bad failures,
stresses, etc?

Would I be correct in concluding that the tank is no longer usable for
compressed air, even if it passes a hydraulic pressure test?

i

That would be the safe course.

That said, how do you suppose those tanks are made? They're welded! I
have welded on compressed air tanks. No problems. But you don't know
if the guy that did the welding on the tank in question was any good,
or if he tested it after welding. Or, for that matter, that they
used it as a pressure vessel after welding since it was separated from
the pump.

Welds near the bottom can burn the galvanizing off the inside,
creating a site for condensate-caused rusting from inside out.