Air Compressor Tank Question

[wsmm]

I have a 5hp cpmressor with an 80 gallon tank. It has a large pipe plug on the side of it near the top. I was thinking of opening the fitting, it I can get it loose and spraying rust convertor into the tank to help protect it. Would this b a good or bad idea. Can I just use the regular nozzle or do I need to come up with some type of tube to direct the spray to te bottom. Has anyone done something like this or something else to protect the inside of the tank. I have a ball valve assembly on the bottom of the tank and pretty much open the valve after every use and leave it open until the next use to dry out the compressor tank.
Thanks for all your hrlp in advance
Bill

 

[ribbitt]

I'd be concerned that rust converter by itself would not hold up over the long run. I bought a new compressor 25 years ago and coated the tank with POR-15, after cleaning the oil out with solvent, then using phosphoric acid rust converter to get any rust out. I opened that big plug a few months ago, and the inside of the tank still looked good. I just thinned out the POR-15 with solvent (Red Kote would also work), poured it in the tank and rolled the tank around for awhile, just like you'd do for a gas tank. Then drained it out and made sure I cleaned out the threads on the drain hole. Rolling around an 80-gallon tank would not be fun, I guess. I don't have any good spraying ideas for you, sorry.

 

[Goose]

If you do any spray painting, I'd be concerned about anything you put in the tank contaminating the air.

 

[wsmm]

I do very little if any spray painting. What I usually do if I have to is use a rattle can. Don't paint much becasue of allergies. If I did spray I would probably use a filter on the gun.

 

[Stephen Newell]

Unless the compressor tank is brand new I don't think you would help it any trying to coat it. If it's already rusting the coating will just hold moisture there. If it's not rusted there would be a certain amount of moisture, dirt or slime that would prevent a coating from adhering.

 

[Jack345]

If your air compressor is a piston type some oil will be in the tank and the rust converter will not have a proper surface to bond. Best leave it.

 

[used red MN]

You are throwing good money after bad. Speaking from recent experience, had a 20 gal. portable the tank rusted holes in. Got a used replacement unit with a bad pump. Already some rusting under way so my thought was same as yours. Had a 1? hole top and bottom. Took a length of chain and put about a dozen pointed body bolts in the links. Put it on a piece of coat hanger chucked in a drill. Spent near an hour runnig it in both holes at all different angles focusing on the bottom half of the tank. Flushing it out with a garden hose. Then let it dry out. Here is the kicker, if you think you are drying out the tank leaving that valve open you are wrong. Even with the two 1 inch holes open top and bottom it still took 3-4 hours in direct sun light at a temp of 75-85 to dry it out. I then applied the rust converter like you are planning. Even with a swab of cloth on the end of a coat hanger the end result was not at all as hoped for in coverage. Will it be better than nothing at all probably, but I don?t think it will pay for my effort. Secondly the replacement unit had a better quality tank to start with but the way the 1? NPT bungs are welded in when the water is drained an 1/8 to 1/4? still remains in the tank. I tried to work the ridge down next to the bung with a burr with limited success. So this will be a run what you brung. Against my son?s better judgment I tried to weld the old one. Which was unsuccessful by the way. I cut the bad section out an made a cut through the weld near what appears to be the most corroded area. It was under 0.020 thick. Can you say boom? Good luck!

 

[David G]

As discussed, you will never get the tank cleaned up good enough for anything to stick on the inside.