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Slipangle 07-03-2007 10:50 PM

Used compressor - rusty tank?
Okay, ultimately my goal is to use this compressor I picked up for $50 for a year, maybe two, until I can get something bigger better and newer. The question is will this one make it and what is the worst that could go wrong? Here's the story.

I've pulled a permit and wired a new 20A 240V switched outlet for a compressor I bought 2 weeks ago, and I'd say that even with doing the electrical work myself, that part cost more than the compressor... No big deal, when I upgrade, the electrical will work for that too and I'd need it anyway.

The story on the compressor was that I bought it from a lawyer with a Charger he's working on and a bunch of go-carts which his son races competitively. Apparently he got it from a friend who races hydroplanes. The story was it worked when it last was used, which I don't know how long ago this was, but I don't think the guy I bought it from ever used it, he apparently got a new larger compressor before he needed this one.

It's a Sears 2hp horizontal compressor, it will be adequate for my cutting tools and probably a DA sander, which is about as much as I'll be using for the next couple years... I'm sure it would be fine for a spray gun, and probably not quite enough for my bigger orbital or line sanders, but I don't think I'm going to get that far in my project for a while either.

When I got home with the compressor and unloaded it, I heard sloshing. I emptied the tank, there might have been a couple cups of brown water and oil in the tank. Presumably this had been sitting in the tank for a couple of years, and presumably the tank hadn't leaked the water, so good and bad.

Yesterday I finished the wiring to the point I could run the compressor for the first time, which I ran it until it reached its shutoff pressure. This morning or afternoon, I noticed a brown spot on the garage floor like rusty water had leaked out from under the tank. The pressure had dropped enough that the compressor needed to run, but the reading on the gauge hadn't obviously dropped.

So, should I be concerned? I have a cheap C-H 110v compressor, is there a way to use the tank off that with the pump and motor of the new one? My dad's old Sears compressor he had given to me before I moved to Indy but left was worn out in the pump (rings were shot) would I possibly be better to try to get that tank to switch in?

Chevrolet4x4s 07-03-2007 11:17 PM

probably didnt get the drain plug tight

oldred 07-04-2007 12:45 AM


Originally Posted by Chevrolet4x4s
probably didnt get the drain plug tight

Don't bet your life on that! :nono:

First thing you need to do BEFORE you run that compressor anymore is make sure that is not a leak in the tank, if it is then the tank is history and under no circumstances should it be used. From what you have described I would be highly suspicious of that tank and I would strongly recommend hydo testing it before use but if there is a rust leak already in it then it is too far gone and requires replacing, NEVER attempt to repair a rusty tank by welding or any other means. How big is the tank? Surplus center had some smaller tanks a while back and I think they are still available at a really decent price.

F&J 07-04-2007 05:34 AM

I bought a new 4hp Sears in 1976 advertised back then as a "special priced model". After several years of hard use, it started blowing head gaskets due to it having a cheapie pump.

A friends father passed away and I ended up with his old Sears 4 hp with a better designed pump, but the guy rarely used it. The bottom of that tank was covered with brazed spots from the old guy fixing rot holes. I just swapped his pump to my good tank.

I then cut that brazed tank in half to see how bad they get. It was deeply pitted all along the bottom. I think a new tank could be purchased at a good price if you shop around. They "should" all be certified, but check on that before you buy.

A 2 hp will have some trouble keeping up with a DA, die grinder, air grinder, but should paint OK.

adtkart 07-04-2007 06:56 AM

Listen to Oldred. Your life or others are not worth endangering for an air tank.

I don't know about the output of that compressor, but I wouldn't expect much from a 2HP.


31choptop 07-04-2007 08:08 AM

as was said earlier I'd run like he77 when that was turned on. its like the air tanks in the 70's that were exploding when filled. all it took was some bad welds and they blew, killing and maiming.put a few companies out of business because of it! its not worth it. use the pump on a new or better tank.please

Slipangle 07-04-2007 08:19 AM

The Sears compressor (going by eyeball guesstimation) is a 30 gallon tank, my newer lower powered C-H is I think 16 gallon... The Sears compressor is rated 6.4 SCFM at 90 psi.

The drain plug wouldn't budge, I had to drain it from the air outlet.

I don't even know if the tank is leaking... The air pressure drop was not enough to read on the gauge, and there is neither an obvious leak at the point of origin of the stain on the floor or a path where a drip depositted rust stain on the outside of the tank on its way to where it dripped to the floor... The paint is pretty clean with a little uniform undisturbed dirt and no signs of bubbling or rust spots.

About all I can think to do is clean the floor, clean the tank, lay down some paper and see if any new stains appear to get a better idea if there's anything really going on.

brian0605 07-04-2007 09:50 AM

If it has mounting pad style feet I would highly recommend attaching it to the floor. If it has an explosion it won't fly around. I had a friend with a small 10 gal portable compressor that he knocked over with his 4wheeler in the shed and he said that thing went crazy. Fortunately for him it went away from him. Brian

oldred 07-04-2007 09:50 AM

I checked those tanks at Surplus center and they are not as cheap as I thought they were at $149.00 for a thirty gallon but this does include a handle and it is mounted on wheels, basically a compressor without the motor/pump. One way to check for a small leak is to spray soapy water on the tank while it is under pressure. From the situation you have described if that thing is more than five or six years old I would not even bother testing it as there is no way of knowing what the inside looks like and it sounds as if it has sat idle for a long time with water in the tank so the rust is most likely extensive. The danger of an exploding tank is just too great to chance IMO and the small cost to remedy the situation in this case is just good insurance.

The tank that F&J mentioned with the brazed spots is REALLY scary because that not only weakens the tank more it is just like plugging a safety valve and I find it hard to believe that people will do that but they do :drunk: Usually a rusty tank will only spring a leak but sometimes the first warning is an explosion! Do yourself a big favor and don't take a chance on a tank with obvious problems and a questionable history.

richard stewart 3rd 07-04-2007 10:18 AM

Check out the old threads on air compressors on this site, there very
informative & there are pictures you may want to see.
Take care,

PS I hope everyone is enjoying the holiday. Keep it safe.

Chevrolet4x4s 07-04-2007 03:19 PM


Originally Posted by oldred
Don't bet your life on that! :nono: ..........

I thought that it had been drained by the drain plug. Mine is a lil tricky sometimes after draining it and thought that it might be the same case.

oldred 07-04-2007 04:52 PM


Originally Posted by Chevrolet4x4s
I thought that it had been drained by the drain plug. Mine is a lil tricky sometimes after draining it and thought that it might be the same case.

My point is if you see dirty water or even rusty water stains on the tank or the floor under the tank it should be checked and determined for sure where it is coming from and it is not a good idea to assume it is just leaking from the drain, which is common BTW. A leak in the tank should be considered a popped safety valve and a warning signal that the tank has reached the end of it's service life and MUST be scrapped. Attempting to repair a tank by welding or other means is like plugging that safety valve and ignoring a warning about a serious danger, in addition welding on the tank usually makes it even more likely to fail catastrophically.

RichardRonnie 03-16-2012 05:41 AM

Hey! I bought a used air compressor and I want to know the ideas on ways to get the loose rust out of this compressor.

johnnyg 03-16-2012 06:20 AM


Originally Posted by RichardRonnie
Hey! I bought a used air compressor and I want to know the ideas on ways to get the loose rust out of this compressor.

Buy a new tank with no rust.

unix 03-16-2012 06:52 AM


Originally Posted by RichardRonnie
Hey! I bought a used air compressor and I want to know the ideas on ways to get the loose rust out of this compressor.

B............OO.................M !!!

Problem solved that should get the rust out for ya. Oh yes please be sure to make a video.

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