# Dangerous tank?



## Greg J. (Jul 18, 2012)

A couple weeks ago I looked at a used air compressor which had been sitting in a garage for 10 years. I pressurized the tank to about 35 psi. The original owner had a replacement for the air tube that runs between the motor and the pump. He had trouble remembering, but said that he thought that when he tried to fix it long ago he wasn't able to get it sealed.

Today (a couple weeks later) I started working on it. The pressure was still at 35 psi in the tank. This would appear to be sufficiently sealed, however (1) is it likely that with a defective job sealing it might leak at 130 psi?

I opened the tank water drain and nothing came out (at 35 psi). I poked a piece of metal up the nozzle and blam, I got a spray of rusty brown-red water (all over the place). I'd estimate it was 1/4 to 1/2 cup. It turns out that the blockage and all the solid matter was/is black. (2) What is this stuff?

(3) Does this tank have a significantly higher chance of exploding at 130 psi than it did when it was new? (My immediate plans are to use it at 30 psi.)


Craftsman 919.165230 vertical 5.5 hp, 130 psi, 25 gal, 8.6 SCFM @ 40 psi, 6.4 SCFM @ 90 psi. GE Motor GE5KCR49TN2312CK


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## tractornut (Sep 17, 2010)

as far as i know the only to know the exact condition of the inside of the tank is to have it tested and recertified if there are any other ways i am not aware of them


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## Greg J. (Jul 18, 2012)

Oh, I've never heard of that. What sort of place will do that?


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## cedgo (Sep 29, 2011)

Insure your pop-off valve is working. 
Generally, a bad tank will develop a pin hole somewhere on the bottom of the tank, not explode. The amount of debris in yours does not seem escessive.


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## pawon (Dec 26, 2011)

Black / brown water with some dirt is quite common in compressed air tanks. 
As said before it would probably not explode just like that, but be sure to test the safety valve.

If it seals perfectly at 35 psi, it would probably seal properly at 100psi.


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