Air tank in AC bay has pin hole. :(

[Chaz]

 Have any of you guys pulled that tank out? I was wondering if there was any tips or tricks to it.
There is a small rusted pin hole in front of the welded seam. It's on the bottom so I'm assuming it's a rust hole from the inside as the outside looks fine. I'm planning on pulling it out and welding up. I'll be doing a little inspection of the whole bottom as past experience has showed there are probably a few other spots ready to blow thru. 
  And of course, this happens AFTER I do my battery bank and box under it so to make it that much more cramped. Figures.

  Not so full of air right now,
     Chaz

[Jerry Liebler]

Chaz,
    It was about 4 years ago that I pulled mine out.  I pulled it to relocate it to the bulkhead between that compartment and the front luggage bay, rotating the tank 90 degrees in the process.  As I recall it was a totally routine disassembly, my challenge was re forming the lines to accommodate the new location.

Regards
Jerry 4107 1120

[gus]

Trying to weld air tank pinholes is an exercise in frustration-from first hand experience. I was told the same thing on this board but I went ahead and tried it anyway. The more you weld the more holes appear because you burn through the rust that is plugging other holes.

Before you start any welding grind off the bottom paint to bare metal and see how many rust spots you find. Each small round rust spot will be a new hole on its way or already there.

[captain ron]

Gus, your preaching to the choir  I think Chaz invented metal

[Sammy]

Chaz and metalworking are like humans and breathing - all automatic. 

[kyle4501]

Chaz, not trying to be disrespectfull (it comes naturally some days  ), but this is directed to those that may not know about welding thin walled pressure vessels.

One is supposed to be ASME certified to weld on pressure vessels over 6" diameter. Thin walled pressure vessels present their own special 'opportunities'.

Do not under estimate the power of compressed air. Many have & survived, but some haven't. & if one busNut doesn't - that's one too many in my opinion.

[Chaz]

Thanx Jerry. I remember you telling me about that. I was hoping it would be just straight forward.
  Charley and Sammy,
   
   Too funny!!! Yeah, I've had my share of playing with metal. And your right, I do love it. But I do appreciate the warning Gus put out. It helps others that may not be as up on the subject.  And Kyle is 100% correct. A person doesn't want to "booger & grind" a pressure tank. I will be TIG-ing this in with stainless.  (I have been tested......... OH, for welding too!  )

  I guess it's just going to be "pull it and do it". I couldn't imagine there being anything else that I could do while I'm at it, but it's worth checking. Finding out there is a better way, or something else to do after the fact, always bums me. And that my fine feathered friends is the ABSOLUTE BEAUTY of this board: 1634 members got my back! 

   Thanx guys! Couldn't do it without ya!
       Chaz

[Dallas]

Chaz,

You may want to bite the bullet and check your local junk yards for a tank.
For what you are going to spend with electric, time, gas and stainless, you could buy a tank or two in excellent condition.
If you aren't against moving the tank location, you could get the air tanks off a IH 9670 that are about the same diameter, but around twice the length.
Morer air is always betterer! 

(Although, I do like to fix stuff on my own more than I like to just buy new parts and throw at a problem.) 

[oldmansax]

I agree with Dallas. You should be able to buy a tank in good condition cheaper and have a better repair. A pressurized vessel should be hydro tested after repairs no matter how good the tech is who repairs the problem. One mistake can be deadly.

I will never forget a picture I saw it a tire repair shop in central Florida. I don't remember the exact circumstances but I remember well the lesson. The caption on the picture read "This is why we we insist on safety". It was a picture of a mans pants that had been blown off of the body after he tried to air up a tire on an old rusty rim. The shop told him they would not air it up because of the condition. He sneaked around the side & did it anyway. It exploded & killed him and injured his son. They found his shoes a block away.

SAFETY FIRST!!!!!!!!!

TOM

[Chaz]

Both good points guys. I totally appreciate the concern!! Truly!!

But there really isn't any boneyards around here that would have a bus like mine. That would take a bunch of time!!!!!! And "fabbing in" a different tank would take GOBS of time also. (I already have all the wall space in that compartment taken up with electrical) I figure - depending on what it takes to get it out - it should only take a couple hours total. The pulling and installing should take the largest amount of time. I have everything else right here.
  And altho 120# of air is a substantial pressure, it's not a big deal for me. Now please don't feel I'm being cocky, I'm not. But I have welded water towers to trombones and most everything in the middle.......including pressure. I can't even count how many hard hydraulic pressure lines I have welded or brazed for local companies on big equiptment. I think they can get up to 1800# if I'm not mistaken. Plus,I have the ultraviolet dye and light to check my work for leaks.
But you are right to put out that word of caution. It can be dangerous!!!!!!!! And being in the welding business since '81 (14 years my own shop with as many as 9 employees) I'm pretty sure I'm still up to the task.    But people who don't have the experience shouldn't try this at home. I am actually the kind of guy to bring it to.

  Good cautionary info fellas. Thanx for the concern. It shows you care. (hard to come by nowadays)
    Chaz
 

[captain ron]

Chaz can weld a pecker on a hummingbird 

[DrivingMissLazy]

Chaz can weld a pecker on a hummingbird 

Or the crack of dawn. LOL
Richard

[Chaz]

Or the crack of dawn. LOL

Why would I want to weld her crack up??   
 
If you can hold that Humming Bird, I'll give it a try!    (his pecker, that is!  :DLOLOLOL)

 

[jackhartjr]

I was going to ask if you could weld it while he is flying!
Jack

[kyle4501]

There is a big difference between the 1800 psi hydraulic & 120 psi air in that that air is compressible & the hydraulic fluid is not.

That means that once there is a leak in the hydraulic system, the pressure drops quickly (unless the pump is running, & even then the energy released is only what the pump is adding.)

A leak in an air system is a bit different since the air compresses & allows the compressors energy to be stored.

For example, a pipe full of water will split when the pressure causes failure. That same pipe can explode if it is filled with air when failure occurs.
That is why pressure vessels for compressible gasses are tested with an incompressible fluid (hydro test) for certification.

There is more stored energy in an air tank than many think. If it took a 5 hp compressor 2 minutes to fill the tank & you release the pressure in a fraction of a second, you are looking at the energy equivalent of hundreds, maybe thousands of HP in that fraction of a second.

Sure, air tanks can be welded. That's how they are made to start with, but you can be sure they knew the quality of the materials they were using.