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How do I know if the compressor tank is safe?

Published Categorized as Air Compressor Tank No Comments on How do I know if the compressor tank is safe?

by David Hemenway
(Denver, CO)

Hello Bill,

I have a late 90s (I think) Devilbiss Air America 5hp 20 gallon compressor and am somewhat concerned with the safety of the tank.

I live in Denver where we have very low humidity most of the year and the compressor only sees three to four tanks a month of use so I drain it about 3-4 times a year and maybe an ounce or two at the most comes out of it.


Do I need to be concerned?

Thanks again Bill?

David Hemenway


Devilbiss compressor tank
by: Bill

David, that’s the $64,000 question.

The only for sure method of testing a compressor tank is to have it hydraulically pressure tested. That process often costs as much as a new tank.

What users often do is use a rubber mallet, with the tank empty of air, hammering on the top, sides, bottom (in particular any seam) and ends to see of the tank dimples easily. If it does, it could indicate a rusting weak spot.

Is the water that comes out always clear, or is it rust red. If red, that’s another indication that rust is happening inside the tank.

Replacing a tank is expensive.

Placing a reasonably heavy duty wire cage around the compressor would prevent flying debris should the compressor tank ever rupture, though when they do, it’s often along a welded seam.

Sorry I cannot give you any more guidance than that. Anyone else?


Hydro Testing of Compressor Tank
by: Anonymous

Check youtube.com for videos on restoring air tanks. Its fairly easy to hydro test your tank if you have a pressure washer.

Fill the tank COMPLETELY with water and check your tank name plate max working pressure. In my case my tank is rated for 175PSI, if you double that to 350PSI attach a pressure washer to the tank and run it up to double your max working pressure.

Make sure the tank is completely full of water.
If it holds, you’re good too go.

Tumble some pea gravel or do some electrolysis on the tank to remove all rust, pour a quart of welding primer in it, roll it around to coat all surfaces and drain the excess out. Let it dry for a few days and it should last many more years.

For the ultimate, run your compressor through an air cooler and then through a moisture separator before it hits the tank and you should have almost no moisture in the tank.

Hope this helps.



Hydro Testing of Compressor Tank
by: Bill

Interesting advice, J. Thanks.

If followed, may I suggest doing so with a great deal of care for the operator and anyone else that may be around.

Also would be good for all of to know if the advice was followed what the results were?

New comment? New question? Please add it here along with photos to help others help you with your compressor and equipment problem!

By Bill Wade

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