Announcement

Announcement Module
Collapse
No announcement yet.

Rusty Compressor Tank

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Rusty Compressor Tank

    Anyone have any good ideas on ways to get the loose rust out of a used compressor I bought? When I open the tank bleed valve the air slowly exits the tank because of loose rust inside the tank clogging the hole. I was thinking about putting a few small ball bearings inside and then carefully rocking the tank around to break the rust loose, but how to get it out? I was going to pump a small amount of a non-corrosive liquid into the tank and then drain it to get the loose stuff out. Any other suggestions? Anyone tried doing this?

  • #2
    Re: Rusty Compressor Tank

    If the compressor is one where the bleed valve can be taken off, then that is a huge advantage. Take it off, and just use a small screwdriver to try to break up and pull out the rust flakes.

    If not, you may have a bit of a hassle. I would suspect that any water put into the tank is not necessarily a good thing, and may only cause more rust to be created/formed/flaked off.

    No matter what, you will need to probably take appart some of the tank's fittings, to allow for removal of the rust flakes. After taking things appart to allow for this, I might go with pouring in a bit of liquid something (discussed below), and using it to remove some of the flaked rust from inside the tank. Then, just pour things out. Now, you will want to run it for a few cycles after, to try to get rid of any liquid residue out. Also, I don't know if I'd want to put certain things into my tank, unless you have a good filter on your air lines, to prevent clogging of your tools, and/or misting through your tool's exhaust onto your workpiece.

    Regarding liquids used, hopefully others chime in. The two that I would think of first is liquid WD-40 and liquid rubbing alcohol. WD-40 is non-corrosive, displaces any water/moisture, and is good for metal surfaces. Rubbing alcohol is the same, and has the huge benefit of evaporating thoroughly in a few minutes, thereby leaving no residue. Certain liquids/compounds, when compressed and under pressure, lead to an easier flashpoint and more of an explosion/fire hazzard. Not sure if WD-40 is like this, and obviously alcohol is flamable. Either way, I would definitely make sure to drain and clean out as thoroughly as possible, and leave the tanks open and evaporating out for many days afterward, to ensure as much residue is gone as possible.

    All this being said, not sure if water might be the better idea in the long run, threat of additional rust aside, and just leave things open for a long time to allow all the water to evaporate completely.

    Hopefully others chime in with what they've done. Wish I was more help, but I'm an aluminum tank proponent now, just for these reasons.

    Comment


    • #3
      Re: Rusty Compressor Tank

      How easy it for you to remove the compressor and motor assembly from the tank? With some units, it's just a matter or disconnecting the compressor regulator and air connections to the tank and then unbolting the motor mount and compressor. This would allow you a lot more flexibility with tumbling the tank with bearings in order to loosen up the internal rust.

      At least, pull the drain valve which will allow you a larger hole to dump the rust particles.

      More of a concern to me would be the extent of the rust and has it marginalized the tank's integrity. See if you can find a compressor service center or a welding/gas supply company that would be willing to give this tank a high pressure test ("burst test"). If the tank is too corroded, it may not be safe, and you surely don't want to be around if the tank ever let go.

      In some case, tanks just spring a leak... but I've seen the rare event where the tank has let go in a much more dramatic way... (read that "explode")!

      CWS

      Comment


      • #4
        Re: Rusty Compressor Tank

        If your tank is seriously rusted inside for safety reasons it should be replaced with a new one and drain it out regularly. Don't take a chance on your old tank failing. They can and do explode like a bomb blast.

        The proper way to test the tank would be using a hydrostatic testing pump. With great care all air is vented out the top and the tank is totally filled with water. It's then pressurized to 150% of the rated or normal working pressure and held for several minutes. Normally they wrap a few cloth bands around the tank and check for expansion and contraction. Unless this is a good size tank with an ASME-NB plate tack welded to it, I really doubt it's worth the cost for testing. I would mush rather replace it than take chances. There should be one or more good size ports in the tank. Remove any fittings and then take a small light and work it into the tank and take a good look inside it.

        As far as cleaning the tank your idea of steel balls should help bust up the rust. A good flushing with water should help get it out. You may want to try adapting some small PVC tubing to a vacuum cleaner and try to suck it out once busted up some.
        Last edited by Woussko; 03-20-2008, 11:38 AM.

        Comment


        • #5
          Re: Rusty Compressor Tank

          Depending on the size of the tank, the exit port on larger ones where the regulator goes on will be of larger size like 1/2" which would make it much easier to work with and even peak in with a flashlight. If it's a small portable it's probably going to be a small 1/4 npt port.

          Comment


          • #6
            Re: Rusty Compressor Tank

            The WD-40 and alchohol could possibly work since both should evaporate rather quickly as long as you give them a chance to do so completely. I still don't like the idea of using anything flammable to clean the inside of the tank. The alcohol might work since it should completely evaporate very fast but oils will stay in for a long time evaporating inside, possibly leaving an explosive air rich atmosphere inside the tank. I doubt there is much danger of reaching flashpoint as the air would have to be compressed thousands of PSI higher but it's possible you'll end up with a flammable mist comming out of the air hoses. The o-rings and seals in air tools will not handle all types of oils either. WD-40 will actually eat through seals of most pneumatic devices so you don't want the stuff in your airlines.

            Originally posted by canucksartech View Post

            Hopefully others chime in with what they've done. Wish I was more help, but I'm an aluminum tank proponent now, just for these reasons.
            The problem with aliminum is it has a finite cycle life before failing. It doesn't matter how small the stress is, it's cumulative. Every time the tank is represurized the aluminum goes through a cycle until eventually reaching it's limit and failing. Structurally it doesn't tolerate damage very well either. If it gets dinged it can be severely weakened at that point. It's good for small portable compressors which tend to have short lifespans anyway. Other metals like steel can have a virtually infinite cycle life if kept within it's tolerances. Titanium would be the ideal material for a tank if it wasn't for the astronomical cost. It will never rust and has even better cycle tolerance than steel while being much lighter.

            Comment


            • #7
              Re: Rusty Compressor Tank

              Sorry I should have specified what type of tank it is. It is a Ridgid OF45150, just a few years old but looks like it was use quite a bit. For those unfamiliar with the compressor it is a 4.5 gal twin steel tank, 3.5 max hp, 150psi max compressor. I can take the bleed valve off and if I can remember correctly I think it is a 1/2" NPT connection. I am going to stick a handful of ball bearings in rock it around a bit then take them out. I will probably use rubbing alcohol as the fluid to get the loose rust out. As long as I can get the loose particles out I will be happy. I looked into getting a new tank but a new tank will run me $85 and I am already $160 into the compressor but I have installed a new cylinder, piston, all gaskets, valves, gauges, and regulator. Aside from the tank and motor it is pretty much brand new and as long as it works and works correctly I will use it. Thanks for all the helpful info everyone. I will let you know how I make out.

              Comment


              • #8
                Re: Rusty Compressor Tank

                Whatever you use to clean out the tank, leave one port open and directed away from the motor. With the machine outdoors run it for about 15 minutes so it blows the vapors out of the tank. For safety I would use water over alcohol. There's water in air and especially when it's humid. That's why you need to drain your tank after using the air compressor.

                Comment


                • #9
                  Re: Rusty Compressor Tank

                  I had a twin-tank, electric motor-driven compressor made by Ingersoll-Rand under their "EnergAir" brand. I bought that in the late 70's, as I recall. Nifty little compressor and I liked the wheelbarrel design.

                  The unit was recalled a few years ago, due to tank leakage and the possibilities of bursting. The tanks were made in Italy, as I recall.

                  Point is, that tanks can be dangerous and once they have shown dramatic rusting, it would be very wise to have it tested or replaced. Unfortunately you've already invested quite a bit in the compressor and with the additional expense of tanks, your probably close, if not over, the price of a new compressor.

                  As a side note, I recall a tank "separating" in our town when I was a teen. It was one of those two or three stage horizontal tank units that they used to install in automotive garages. Fortunately the failure happened in the early morning before it opened for business.

                  The tank sheared, blowing the top mounted compressor through the roof; it came down on the street side of the fuel pumps. A portion of the tank went through the concrete block wall separating the bays from the office. Blew out the front windows, and buckled the wall nearest the compressor.

                  I can't imagine what it would have done to a wood frame house.

                  CWS
                  Last edited by CWSmith; 03-20-2008, 04:04 PM.

                  Comment


                  • #10
                    Re: Rusty Compressor Tank

                    Originally posted by Velosapien View Post
                    The problem with aliminum is it has a finite cycle life before failing. It doesn't matter how small the stress is, it's cumulative. Every time the tank is represurized the aluminum goes through a cycle until eventually reaching it's limit and failing. Structurally it doesn't tolerate damage very well either. If it gets dinged it can be severely weakened at that point. It's good for small portable compressors which tend to have short lifespans anyway. Other metals like steel can have a virtually infinite cycle life if kept within it's tolerances. Titanium would be the ideal material for a tank if it wasn't for the astronomical cost. It will never rust and has even better cycle tolerance than steel while being much lighter.
                    Egh, if I get 5 years out of my little Ridgid 2.5 gallon aluminum twinstack, then I'll be happy. Figure that the piston/motor will go in that thing well before the tanks will. If I can make 10 years, hey, even better. I figure I'd hear some sort of a recall or warning at some point as to when it's time to replace it. And, with it being smaller tanks and aluminum, fingers crossed that if it fails, it simply tears open due to being a softer metal, rather than shrapnels. If not - it's just a small hand grenade rather than a large bomb!

                    Comment


                    • #11
                      Re: Rusty Compressor Tank

                      Are compressors eligible for the LLSA?

                      Comment


                      • #12
                        Re: Rusty Compressor Tank

                        Nope, 3 year warranty.

                        The air/pneumatic tools are eligible for the LLSA - nailers, pinners, etc.

                        Comment


                        • #13
                          Re: Rusty Compressor Tank

                          If you are getting actual flakes of rust out of it I'd replace the tank.General rule of thumb I was taught is the thickness of rust is double the amount of steel rusted away.Most the tanks are pretty thin steel so I wouldn't trust it.On the other hand I've never seen a tank that didn't spit rusty water from the drain after a few months.
                          Sam

                          Comment


                          • #14
                            Re: Rusty Compressor Tank

                            That's what I get for trying to save a few bucks by buying a used compressor and then fixing it up. I could also frame a plywood box to fit over the tanks that I will put in place whenever the compressor is on. I would make it just big enough so that it doesn't cover the motor but just the tanks. This way in the rare instance that the tank did fail there would be something in place to block the shrapnel. I know I should probably just buy a new tank and I probably will at some point but this temporary remedy would at least keep people safe for the time being. I want to be frugal but I want to be safe and smart at the same time.

                            Comment


                            • #15
                              Re: Rusty Compressor Tank

                              Take the advice from ThreeCreek3, regarding accessing the possible damage caused by corrosion.

                              If your tanks eventually spring a link, your plywood container may be of some use, other than just blocking the visual inspection. However, if the tank bursts, the plywood would most likely just add to the shrapnel. I think I'd still look into a local place that could do a pressure test on it. Some welding or industrial suppliers of bottled air/gas routinely run these on their bottles. It doesn't hurt to check around.

                              CWS

                              Comment

                              Working...
                              X