compressor from garage sale

[woodchucker]

So if I can't scrub it off, will it still work?

[Phil Kangas]

"-MIKE-" <

xxx This sounds like an acetylene generator incident. They were common many years ago. xxx

[Keith Nuttle]

waaaaay better than

necessary: water and

there will be no

radiators as well.

amount of

I would believe that a cast iron boiler is several times thicker that an air compressor tank. I am sure the radiator is.

[Larry Blanchard]

Well, it might just be the normal corporate CYA, but every compressor manual I've seen says to drain on a regular basis - like every time if you use it infrequently.

[woodchucker]

That just makes good sense too. and it is probably not just CYA,

[Ed Pawlowski]

May have been enough oil mixed in there so it was protected. The wet portion may be better than the dry portion.

[Ed Pawlowski]

According to the inspector that does out tanks at work, they pin hole rather than explode. In MA, tanks have to be inspected every two years. They use an ultrasonic thing and it gives the wall thickness and can be done while running.

[-MIKE-]

As I wrote, you don't drain it because of some perceived danger or rust build up. You drain it to improve performance of the pneumatic tools using the compressed air.

[Lew Hodgett]

"-MIKE-" <

------------------------------------------------------------------ Don't want to rain on your parade, but how big do you think those pressure cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.

Lew

[clare]

Yes - better than scrubbing it off. The iron phosphate helps prevent further rusting.

[-MIKE-]

I hope you're joking. There was a lot more than air in those things.

[Lew Hodgett]

------------------------------------------------------------------

"-MIKE-" wrote:

-------------------------------------------------------------- Absolutely not kidding, shrapnel is shrapnel regardless of the source.

Lew

[-MIKE-]

That's kind of the point. There is no shrapnel when an air tank "explodes." Why do I keep putting explodes in quotation marks? Because of the very misconception you have and others are having. The energy from a bursting air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an air tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were packed with ball bearings, either. sheesh.

[none]

On Sun, 05 May 2013 17:16:51 -0400, woodchucker

In other words, you're afraid that the tank might be on the verge of blowing up in your face, right?

Compression takes in poor condition, usually develop pinhole leaks first, which would indicate that it's time for you to replace it. Of course, you could replace it now, but most people continue to use them until they start to leak.

In other words, you can use it until there's a problem.

[none]

On Sun, 5 May 2013 21:11:50 -0700, "Lew Hodgett"

Those pressure cookers were shrapnel accelerated by explosive. That's considerably different than a compressor container giving way to air pressure. Almost invariably, the compressor will burst at a pinhole or maybe a little larger area.

[Doug Miller]

Keith Nuttle wrote in news:km74a5$9jt$ [e-mail]:

Indeed it is. But the water sits there longer, too. The point remains that once the oxygen in the system is used up, no further oxidation (read: rusting) can take place unless fresh oxygen is introduced.

[Sonny]

tic acid in the tank after, just water or baking soda...

Flush with water. It shouldn't take much acid (1-2 cups) to rinse/slosh th e bottom of the tank, where there would likely be the most rust. Concrete is cleaned with muratic acid and simply rinsed with water. The old saying is to add acid to water, to prevent a splattering reaction when mixing the two. In this situation, adding water to the acid (to neutralize it), insid e the tank, shouldn't be a problem, plus it would be difficult to pour out the acid, first, into a safe container without having it pour irradically f rom the petcock hole. Further, pour the mix into a 5 gal bucket of water, to further dilute it.

Maybe/yes, to some extent. I've used it to assist in removing rust on stuf f at home(shop) and used it on (our past) boat dock surfaces. Since you ca n't readily see inside the tank, we don't know if there is significant rust in there, or not. Muratic acid is more readily available, I think, and wi ll help loosen at least some rust without having to scrub, since you can't readily scrub the inside. Any potential loose rust may block the petcock, in the future, so removing the most you can is preferrable. Using acid is the easiest way, IMO, hence my entertaining the idea of using the acid as a "rinse" or possible (assistant) rust remover.

Summer jobs, during college days, I worked on a dredge boat/barge along the Gulf coast. There were times when we'd clean parts of the deck for repain ting. An acid was used to help remove (or treat?) the rusted areas. I don 't recall what acid was used. We'd slosh it on, do some minimal scrubbing, then rinse with water. On tough or deeply rusted areas, we'd use a grinde r to remove the rust, best we could. Apparently the acid "treatment" did s ome kind of good.

Muratic acid is pretty potent. If spilled on the outside of the tank, it w ill likely peel the paint off, fast.

Sonny

[Doug Miller]

"Lew Hodgett" wrote in news:51872d87$0$28468$c3e8da3 $ [e-mail]:

For someone who claims to be an engineer, you have some odd notions. Those pressure cookers were ruptured by exploding gunpowder. Do you *really* think that the pressure developed by an air compressor (9 to 10 atmospheres is typical) is anywhere nearly comparable to the pressure developed by igniting gunpowder in a small confined volume? Do you *really* think that a bursting compressor tank will create the same kind of "shrapnel" as a pressure cooker that was packed with ball bearings and nails?

[Larry Blanchard]

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the pressure cooker we could come up with a pressure.

[Doug Miller]

Larry Blanchard wrote in news:km8ne6$4hj$ [e-mail]:

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25 atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the case. Suppose the interior volume was reduced by half, by the ball bearings and nails these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a kilogram of powder would generate pressure well over 100 atmospheres.