compressor from garage sale

[woodchucker]

Hey, I bought a compressor from a garage sale yesterday. Paid $20, seems to be between 13 and 20 gallons. What I wanted was an oil type compressor that uses a belt.

I could not take the oil less type of noise anymore.

I thought I was taking a risk, pretty rusted on the outside, but didn't appear deeply rusted. I shook the thing did not hear water in it (WRONG)...

When I got it home still did not hear water in it... opened up the petcock after charging it up and holy crap the most rusted water... and probably a pint to quart of water came out.

So what chance do I have of saving this tank? Where I used to live we had a scales air compressor place nearby but they closed... I don't find any of them around any more.. not close by. The rust on the outside is all superficial and can be sanded and painted ... I need to get into the tank with a 3/4 square end and see.. Anyone have some real info on how to treat this?

Thanks.

[-MIKE-]

I guess I don't understand what's to save. Does it still compress air? You drained out the water. Put a filter on the output and use it.

I think we'd all be surprised by how much water and rust are on the inside of the tanks we use every day. :-)

[woodchucker]

Well, this tank hadn't been used for years the owner said. I let the water out of my tank weekly, how long do you let it sit there. I figure that years of sitting means deep rust inside. Based on the stink of that water, I'd have to say it's been in there a long time.

[woodchucker]

I also remember that there used to be an additive to tanks to protect them. I knew what it was 30 years ago.

Might be too late, but anyone know what the name is.

[Keith Nuttle]

I would believe that the question is not how much water or how much rust, but what is the remaining thickness of the metal making up the tank. If the tank has sit for years has the bottom nearly rusted through?

If it rusted and significantly decreased the thickness of the tank wall is it general or is it such that when it fails it will pin hole and leak slowly or fail catastrophically.

I have never seen a tank fail, but.................

[-MIKE-]

I'm going on 13 years with my current compressor and it work like the day I bought it. I think i remember letting a few ounces of water out of it several years ago. Yes, it was brown.

To the best of my knowledge, emptying water is important to keep water out of your pneumatic tools and the finish material you might be spraying using the compressor.

I don't think it affects the performance of the compressor.

[woodchucker]

Years ago I read about a tank having a catastrophic failure. It didn't just pinhole, it blew from rust.

So I worry, I wanted to bring this into the basement. My current one wakes me up at night when I forget to shut it...

This one will be quieter if I forget. But I need to know it will be ok.

[krw]

I put mine in the garage and piped air from there. It might be a little more of a challenge in this house. I'll see in a few weeks (depends on exactly where walls line up - might be very simple).

[Lew Hodgett]

------------------------------------------------ So what else is knew?

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

-------------------------------------------------- So the owner is a little forgetful.

Question: What is the condition of the relief valve?

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

------------------------------------------------------ IMHO, only a fool would keep and air compressor in the basement or other confined space.

When it comes to pressurized vessels around your home, assume they are going to explode and plan accordingly.

Lew

[Sonny]

Well, it may have had a pint/quart of water, but the rusting factor would d epend on the amount of oxygen reacting with the iron to produce a quantity of rust. In a closed container, the rust may be much less than if contents were exposed to more open air.

Not just open it, but can you remove the whole petcock assembly, without br eaking it? What size hole is in the tank, there, 1/2", 3/4"? If you can r emove the assembly, rinse out the tank, well, then rinse with denatured alc ohol. Allow to dry, as best it can, before reinstalling the petcock.

If I had a questionably badly rusted tank, I might entertain the idea of ri nsing/sloshing the bottom of the tank with muratic acid, to see what all mi ght be washed out. Rinse with water, afterwards. I would think the very bo ttom is rusted the most, if significantly.

Sonny

[Puckdropper]

Keith Nuttle wrote in news:km6j8p$2r0$ [e-mail]:

I saw one failed intentionally on TV. I think it was Time Warp where they dropped a 5 or 10 gallon tank off a building on to a spike. Big noise, lots of pressure released, and the tank went flying. Very fun to watch.

Puckdropper

[Doug Winterburn]

Don't know about that stuff, but I put the HF automatic compressor drain on mine:

I did have to fart around and replace the plastic tubing with copper tubing. It's been working fine for about 12 years.

[-MIKE-]

I keep hearing about it, too, but it's always a friend of a friend of an uncle's boss. And I hear about it being from rust, too, but it's never confirmed. There are always other factors responsible when investigations are done. I've seen articles about talks in big shops "exploding" and causing damage and injuries. These are usually big, big tanks and the injured were standing nearby and got cut by metal shards still attached to the tank.

13-20 gallon tank isn't going to "explode" with enough force to cause the kind of damage you read about. BTW, when the pressure in mine gets to high, the pressure release valve lets out a bunch of air. If you're doesn't have one of those, it's probably a good idea to instal one.

[krw]

depend on the amount of oxygen reacting with the iron to produce a quantity of rust. In a closed container, the rust may be much less than if contents were exposed to more open air.

An air tank has plenty of oxygen in it. High pressure == more oxygen.

breaking it? What size hole is in the tank, there, 1/2", 3/4"? If you can remove the assembly, rinse out the tank, well, then rinse with denatured alcohol. Allow to dry, as best it can, before reinstalling the petcock.

It's just going to get "wet" again, at the first use. It's sorta unavoidable, unless you live in AZ. ;-)

rinsing/sloshing the bottom of the tank with muratic acid, to see what all might be washed out. Rinse with water, afterwards. I would think the very bottom is rusted the most, if significantly.

That sounds like a really bad idea. The rust isn't going to hurt anything more than it already has. HCL does corrode steel, which is

*not* useful. If the worry is polluting the air stream, filter it. If that doesn't work, filter it some more. ;-)

[woodchucker]

That might be true, guess I am that fool. So I guess in your mind my garage might be better. In my mind neither is great. But because it is in the basement it gets taken care of way more than it would in the garage.

[Doug Miller]

woodchucker wrote in news:8cydnWPaAs7YURvMnZ2dnUVZ [e-mail]:

When there's a lot of water in the tank, "hadn't been used for years" is waaaaay better than "used it every week".

Water, by itself, doesn't cause rust. For iron to rust, two things are necessary: water and oxygen. Once all the oxygen in the tank has been converted to iron oxide, there will be no further rusting.

Case in point: hydronic (hot water) heating systems -- such as the one in my house -- typically have cast-iron boilers, and many (mine included) have cast-iron radiators as well. Water normally sits in these systems for *decades* without any damage to the cast-iron components. Yes, there's some rusting internally, but not much. Once the small amount of dissolved oxygen is used up, the rusting process stops.

[HeyBub]

From Wikipedia:

--- begin quote Phosphoric acid may be used as a "rust converter", by direct application to rusted iron, steel tools, or surfaces. The phosphoric acid converts reddish-brown iron(III) oxide, Fe2O3 (rust) to black ferric phosphate, FePO4.

"Rust converter" is sometimes a greenish liquid suitable for dipping (in the same sort of acid bath as is used for pickling metal), but it is more often formulated as a gel, commonly called "naval jelly". It is sometimes sold under other names, such as "rust remover" or "rust killer". As a thick gel, it may be applied to sloping, vertical, or even overhead surfaces.

After treatment, the black ferric-phosphate coating can be scrubbed off, leaving a fresh metal surface. Multiple applications of phosphoric acid may be required to remove all rust. The black phosphate coating can also be left in place, where it will provide moderate further corrosion resistance (such protection is also provided by the superficially similar Parkerizing and blued electrochemical conversion coating processes).

--- end quote

This is how "black pipe" (used for natural gas distribution) is created.

And, from one blogger:

"Look for it as Metal Prep oluton. It's available at any lumber yard, borg, or hardware store in quarts and gallons in plastic bottles. I use Jasco out of blind brand loyalty but it' a good consistant product. It has tuff in it that makes it work better than the plain acid. I dilute it 10 to 1 in a 5 gallon pail. When the blue color fades the acid has pooped out so add more.

"It's sewer safe when exhausted. Or since the spent solution is mostly iron phosphate it makes good fertilizer. Run it through a proportioning squirt nozzle and water your flowers."

[woodchucker]

depend on the amount of oxygen reacting with the iron to produce a quantity of rust. In a closed container, the rust may be much less than if contents were exposed to more open air.

breaking it? What size hole is in the tank, there, 1/2", 3/4"? If you can remove the assembly, rinse out the tank, well, then rinse with denatured alcohol. Allow to dry, as best it can, before reinstalling the petcock.

rinsing/sloshing the bottom of the tank with muratic acid, to see what all might be washed out. Rinse with water, afterwards. I would think the very bottom is rusted the most, if significantly.

Sounds like that might not be a bad idea. Gotta see if I can get a 3/4 square drive to remove the 2 plugs, it would allow me to , the petcock I usually replace with 90 street and galv pipe to a ball valve. Don't understand petcocks.. pain the ass and the ball is worth the money to quickly release the water.

how do I neutralize the muriatic acid in the tank after, just water or baking soda... Will that clean off most of the loose rust?

[woodchucker]

waaaaay better than

necessary: water and

there will be no

radiators as well.

amount of

Makes sense.

[clare]

depend on the amount of oxygen reacting with the iron to produce a quantity of rust. In a closed container, the rust may be much less than if contents were exposed to more open air.

breaking it? What size hole is in the tank, there, 1/2", 3/4"? If you can remove the assembly, rinse out the tank, well, then rinse with denatured alcohol. Allow to dry, as best it can, before reinstalling the petcock.

rinsing/sloshing the bottom of the tank with muratic acid, to see what all might be washed out. Rinse with water, afterwards. I would think the very bottom is rusted the most, if significantly.

Buy , rent, or borrow an "inspection camera" - remove a fitting and poke the camra in to see what it looks like. If you can't tell, rince the tank out untill it is clean and try again. Any significant pitting will show up.