air compressor tank bung

[Citation]

It very well might have burst if he didn't weld on it though, correct.

I think you missed my point. If a tank starts to leak then it's time to retire it. If it leaks in one spot it is likely to be weak over a larger area. So in this case if he retired the tank when it first leaked this wouldn't have happened.

 

[jonshonda]

Huh-huh...bung!

 

[laser3kw]

Is it just me, or does that bird-**** weld around the drain look like it had some home-made repairs from previous leaks?

Yup - and they wonder why there was rust in the tank. Probably didn't drain it often. Glad no one was hurt.

 

[Under_Pressure]

It very well might have burst if he didn't weld on it though, correct.

I agree that the tank very likely didn't fail BECAUSE of the weld- i.e. because of the process of welding itself. It failed because of corrosion. But it failed in the way it did because a weld was used to mask a warning sign that should have led to a more thorough evaluation of the tank before deciding to just throw some weld on the leaking area and keep rolling.

 

[Under_Pressure]

When I had my small engine shop I had a customer ask me if I would sell him and engine, then mount it to a air tank and compressor he provided and get it running. Sure, no problem. I got is ll together and ran it and it wouldn't make pressure. I shut the unit off and could hear air hissing. The tank was cracked around the leg near the bottom. The customer asked me to weld up the crack and I refused. He gave me some **** about it not working, I told him it wasn't my fault the equipment he provided was defective. He paid me and took the unit and left. He called me a couple days latter and told me he had a friend weld it and it works fine! I told him, good luck and never heard from him again.

Yeah, I would never recommend performing an "unauthorized" (i.e. not done by an R stamp holder, assuming it's an ASME tank) weld or repair on a pressure vessel that was not my own, and certainly not as part of any kind of business or for-hire deal. Not even weld up a pinhole, much less repair a crack. Cracks of course are particularly concerning because they tend to want to keep going and it's hard to know that you have completely stopped it. Normally I would recommend scrapping any tank that has a crack; if it had to be repaired, however, to start with I'd want to grind out the crack and some distance on each end, then PT or MT to make sure I was beyond any subsurface crack propagation before welding up and then PT/MT again.

 

[Wrench97]

It very well might have burst if he didn't weld on it though, correct.

It didn't burst because he welded on it, it burst because the tank was already failing when it was welded and continued to fail.
Now maybe if he welded a new bottom section on it would have survived.........................

 

[raffaelli]

During my garage remodel, the drain plug on my 60 gallon tank broke off leaving the thread of the value in the bung on the bottom of the tank. I tried to remove the part left behind. It would not come out and now have no faith in the threads in the bung even if I do get it out.

Do I try and remove the bung and replace? Or can I drill it out and tap for a larger drain size? I half-asses tied to get the bung out and I do not think it will move very easily.

 

[Wrench97]

Cut down a hacksaw blade and cut a slot or maybe 2 in the broken fitting then collapse it with a small punch.
Trying to get the bung out of a old tank is usually a lot harder to do then a broken fitting.
Was the valve brass or steel?

 

[raffaelli]

Cut down a hacksaw blade and cut a slot or maybe 2 in the broken fitting then collapse it with a small punch.
Trying to get the bung out of a old tank is usually a lot harder to do then a broken fitting.
Was the valve brass or steel?

Cheap and thin brass fitting. I will give that a try.

Drill and tap if the threads are no good?

 

[Wrench97]

I would attempt to redrill to the same size tap first. a lot of those bungs get really thin if you try to drill up to the next size.

 

[raffaelli]

thanks

 

[Bmw4life]

You guys cutting up the bungs, where do you get a new one?

I can't seem to remove mine, gotta order 55mm socket and try with the impact gun.

But I don't see any of them bungs for sale

 

[cvairwerks]

That's actually a reducer. Any decent place that deals with metal pipe should have them in the fitting selections.

 

[FTG-05]

I had the same problem years ago on my IR 120-gallon tank I bought off of CL. I welded a 1" nut to the bung and even with cheaters couldn't get it to budge. I took it to a local tire shop; they tried as well, with no luck as well.

Then a senior tech got involved. He grabbed a 1" impact, hooked it up to a 1/2" airline, then went to work. Came off like butter. Still got the bung around here somewhere.

 

[The Cobbler]

I suspect the bungs are loctited in place to prevent tampering

 

[5ubtle]

8 foot cheater bar.

 

[Wrench97]

A little heat will melt the loctite.

 

[Mandres]

Good info in this thread. My compressor has been leaking down overnight and I traced it to the threads of the bung/reducer fitting on the bottom. Going to try cracking it loose tomorrow to see what condition these threads are in.

 

[alabamatoy]

I had a friend solve this for me. He heated each bung very hot with MAP gas then soaked the thread area to cool with PB Blaster. Repeated 3 times, used an entire fresh can. Burning PB has pretty unforgettable smell, we'll both probably die of lung cancer. Then he used his 3/4 in drive Milwaukee and they finally came loose. Made a mess, but it worked.
Wire brushed all threads, then reassembled with pipe dope. No leaks!

 

[Mandres]

Well I'm failing miserably trying to get the bottom bung free on my 60 gallon. I drilled a hole and tried a large npt style EZ out but it can't get a good bite in the cast iron. Does anyone have a 65mm socket I can borrow, oh and a 1" impact gun lol...?

Tomorrow I'm going to try to drill and chisel method. Hopefully I'll have better luck.

 

[Mandres]

Victory is mine! Mapp torch, PB blaster and my trusty old Ingersoll Rand impact gun.

 

[Beerhippie]

I had a friend solve this for me. He heated each bung very hot with MAP gas then soaked the thread area to cool with PB Blaster. Repeated 3 times, used an entire fresh can. Burning PB has pretty unforgettable smell, we'll both probably die of lung cancer. Then he used his 3/4 in drive Milwaukee and they finally came loose. Made a mess, but it worked.
Wire brushed all threads, then reassembled with pipe dope. No leaks!

I use the heat/penetrant trick on a regular basis--but try to do it outside whenever possible--and stand upwind!

Combined with some impact, it works wonders. Hitting near-red-hot rust with the penetrant (I use Kroil for the most part (because I scored a bunch at a barn sale cheap)) seems to actually reduce the rust to a fine, black powder. Burning Kroil smells different from PBB, but still doesn't feel good to breathe.

 

[rlitman]

...Hitting near-red-hot rust with the penetrant...

Next time try heating the metal and then touching it with a candle. The wax will resist burning up into a carbon mess for longer than penetrating oil, and at torch temperatures, wax is just as thin a penetrating oil anyway.

 

[Beerhippie]

Next time try heating the metal and then touching it with a candle. The wax will resist burning up into a carbon mess for longer than penetrating oil, and at torch temperatures, wax is just as thin a penetrating oil anyway.

Sounds good--but which brand of candle?

 

[OccupantRJ]

Last one I removed was an external square drive plug and it did not plan to move. I chained the tank down horizontally to my 800 lb table with two chains and chain binders, soaked it with Kroil, heated it with an oxy/propane torch, and hung off the end of an 8 foot cheater jolting up and down to finally break it loose.

 

[rlitman]

Sounds good--but which brand of candle?

That depends. If you're planning to flip something, a chocolate chip cookie scented candle might be best. If you're working in the winter, I recommend ginger snap. If you're "one of us", then "old screwdriver handle" might be just the ticket.