Old compressor tanks are a time bomb. Most cheap compressor tanks are not
ASME rated nor tested. Rust on the outside is not the problem. It is the
rust on the inside from condensation over the years, AND when they go, they
really go.

One of our EAA Chapter 75 members brought in a tank that had split from end
to end and I wrote about in Sport Aviation. Then I had several others relate
their stories... Like went to town and came back to a hole in the garage
roof. Or... Missed me by inches but ruined the overhead door. And then there
are those not so lucky that can't tell a story as they died.

Many compressor sales agencies can and will do a hydrostatic test. Involves
filling with water then running the pressure up to 150% of working.
Commercial places have to do this on a regular basis.

Before you use this "freebie" Have it tested for your health.

--
Cy Galley
EAA Safety Programs Editor
Always looking for ideas and articles for EAA Sport Pilot
"Michael Horowitz" wrote in message
...

thanks - MIke

On Sun, 12 Nov 2006 11:04:04 -0800, "John Kunkel"
wrote:


"Michael Horowitz" wrote in message
. ..
Someone gave me a Speedaire Model 3Z394 airtank.
I know nothing about its integrity or working pressure.
1. If you own such a model, could you tell me the max safe tank
pressure?

That model was originally powered by a 3/4 hp motor so I would guess it
has
a shutoff pressure of 120 psi.

2. How can I determine if the tank (which as some rust on the outside)
still has its integrity?

Only a hydrostatic test can prove the integrity.