Compressor Drain

[Michael Gabbay]

Well after reading the post the other day about a blown compressor, I made it a number one priority to run to HD and pick up a 1/4" street ell, 1/4" x 4" brass pipe and a 1/4" ball valve. This afternoon when I got home from work I installed it. It was about 15 minutes worth or time and OH WHAT A DIFFERENCE!

Now draining the tank is just a quick turn of the valve for about 10 seconds or so. This is a MUST do for all compressors.

I'll post a pic as soon as I can.

Mike

[Ernie Hobbs]

Yeah, after that post, I went out and drained my 10-year-old Devilbiss compressor for the first time. The sludge that came out was very nasty. Any advice about how to clean the tank out really good?

[Michael Gabbay]

Here's the pic.

[Don Baer]

Every time I read one of these posts I say to my self "Self, you REALY REALY need to o that next time you are in the shop", Then I forget. Going to make sure it gets drained tonight.

[Steve Clardy]

Yep. MInes been that way for several years now. I have a hose on it too, directing the water under the rollup door. I TRY to remember to drain it daily, as it runs a lot.

[Mike Stanton]

I open my drain every night and drain water ultil it stops then close it. I don't thinkit is nessary to drain all the air. Then next time it is easyer to fill it. Mike

[Dale Thompson]

Michael,
You have started an excellent thread in terms of the safety of compressor tanks and pressure tanks in general. There are a number of federal (CFR)codes on the testing and retesting of pressure vessels. These can be quite cumbersome and expensive.

On the other hand, there are ways of performing very simple and "free" tests on your tank to get a general idea of its condition. Perhaps the best and easiest of these is referred to as the "ring" test. Simply tap your tank with a small metal hammer. If you get a "ringing" sound, the tank should be OK. On the other hand, if you get a "dull thud", the interior of the tank is seriously corroded and you will place "life and limb" in jeopardy by applying pressure to that tank. Even draining your tank on a regular basis is not necessarily a guarantee that your tank will maintain its structural integrity. Corrosion will attack a "corrosion point" in the tank and the water vapor left, even after a "drain", will not curtail that attack. A "salt water" environment can quickly accelerate this problem.

The CFR (Code of Federal Regulations) normally requires a hydrostatic test at 5/3 of the intended MAXIMUM operating pressure of a tank. Obvious external corrosive "pitting" and failing the "ring test" disqualify the tank from being rehydrostatically tested.

My point is, be careful with ANY pressure vessel. They are all potential rockets or bombs.

Dale T.

[Dale Thompson]

A tank that is frequently pressurized and depressurized is much more likely to fail than a tank that is under pressure on a constant basis. It's called "metal fatigue". I would suggest that the former is quite common with a home or small shop compressor.

EGADS!! Now I know why I use a bicycle pump to run my framing nailer and other pneumatic tools! YEAH RIGHT!!

Dale T.

[Randy Meijer]

Seems to me that no matter how often you drain your compressor that there will always be some moisture left in the tank. Do compressor manufacturers coat the insides of the tanks with rust reisitant coatings or do we just have to expect that our tanks will rust out sooner or later?? I'ved seen posts about folks who have had compressors for 20 years.......how much of a problem is a rusty tank. In the real world can we expect the compressor to fail before the tank rusts out?? Is there something that could be put in the tank to reduce the rust problem??

[Bill Lewis]

Randy,

Being one that had to replace a tank on a compressor (bought it used) I can tell you that It is very doubtful that the manufacturers are doing anything to the inside of the tanks. The replacement tank I bought (www.mscdirect.com) was primed on the outside, and bare metal on the inside. I suspect that this is the same condition that the manufacturers receive them too.

I considered coating the inside, but I couldn't decide if that was a good thing to do or not. It could lead to the coating flaking off over time, and getting in to the lines, or the drain.

BTW, I found out later that my compressor was built in 1967, and yet it had an ASME standard tank which was a direct replacement and a perfect fit. You gotta love standardization! Oh, and yes I really need to remember to drain my tank this weekend, thanks for the reminder!

[Bruce Overholt]

Interesting thread. Right now I own a PC Pancake Compressor. I bought it because of the free finish nailers that came as a kit with the compressor.
However, I have come to find that I really use my compressor a lot for blowing saw dust off tools and out of my garage. I will eventually would like to to get a larger stationary unit.
I realize the the pain in draining a large tank daily. I often wonder at what point or tank capacity that one might stop thinking about draining the tank daily?
Just a thought...

Bruce

[Kirk (KC) Constable]

I have the 60 gallon PC. I drained it for the first time in a long time a couple weeks ago, and got an alarming amount of water out of it (coffee can full). I checked it yesterday and got nothing. It stays full of air and seldom cycles, so I suspect that will limit the amount of water. I'm gonna try to remember to open the valve every week or two in the future.

KC

[Jack Wood]

I have an old old old compressor and after reading this thread I went out and drained it and yuck! There was what appeared to be oil mixed with the water, that can't be a good thing can it? I guess that the pump is failing and letting in oil to the tank? Oh well, I'll show this to the wife and tell her I just gotta replace this death machine before someone gets hurt Any suggestions on a repalcement? I don't spray paint, I just use it to run a brad nailer and blow dust out.

[Aaron Montgomery]

I did this back in '03. I can tell you that the compressor gets drained a whole lot more than it used to. (never) I've got a clear plastic drain hose (from the furnace humidifier project) that goes into a Gatorade bottle. Makes it real easy to see what comes out of the compressor.

[Michael Gabbay]

Hey I'm gald I'm helping to bring the compressor safety issue to light. I also have wondered why manufacturers don't coat the inside with a corrosion resistant membrane. I doubt the cost would be all that much.


My next modifcation is to build a cabinet around the tank so in case there is a failure, it will help reduce the impact to those around the unit. I keep my compressor in the garage and have an air line running into my basement shop.

Mike