Found the source of the leak. It looks like some sort of electrolysis was happening to two spots on the bottom of the tank. The worse spot had developed a pretty good sized pin hole leak. I opened up the spot with my screw driver. So, what do people normally do for this type of leak? Does one cut out the bad spot and weld in a new piece of aluminum or does one simply weld on a patch?
Welding on a fuel tank can get pretty exciting. Not the smartest thing to do.
I would put a patch on bottom corner or whole bottom. A competent welding shop should have no problem if it's aluminum. Tig or Mig. Even some radiator shops can do it. Just clean (steam) tank first. Have done many of fuel and air tanks the same way. Test with air and Low Pressure. 5 to 10 lbs. only. Looks like it's been rubbing on something by pic number 3. Where are you located??
When I worked in a junk yard we were never allowed to get a welder or torch near a tank, no matter how dry it was or how long the vehicle sat in a pasture.
We were only allowed to remove then by cutting the straps with an axe. Too many stories about tanks, (dry old ones) blowing up.
Aluminum will absorb fuel, one reason used aluminum is hard to weld, there is a procedure that calls for using steam to sweat the fuel out. I'm sure if you Bing it you will find something on it.
Jon i understand about the fuel dangers and hope everybody else does also. Steam it out and you won't have any water vapor to dry out later. Most shops will also run nitrogen inside under low pressure while welding if still unsure. I wouldn't be bothered if I was doing it. Of course I have been welding for over 40 years and still have all explosion meters and certifications including aircraft. Welded up a lot of alloy landing gears that had cracks from hammering the ground on hard landings. Just make sure you are dealing with somebody insured and knows what they are doing. Just another day in the park. No problems with this simple job. Just expect to pay that expert.
Still have a mobile Lincoln Ranger Gas Welder out in the barn with a Hi Freq unit, trailer mounted just for this type of welding. Hadn't started the puppy in a while as I've gotten lazy and rich from welding fuel tanks. LOL.
I suppose that one question I would have is about how many other spots there are that are just waiting to open up and start leaking. If I were going to the trouble of taking the tank to a welder, I would consider putting a whole bottom plate on it.
I have repaired gas tanks using JB Weld that seemed to last indefinitely though.
I would do the whole bottom as procedure would be the same and lay it over the existing one. Good welding shop would know the properties on the aluminum as there are different grades of the metal and alloy's. Different filler rods also. Don't take it to a amateur. Stay away from the JB weld, or I would as that's a lot of static pressure from a hundred or so gallons of diesel fuel.
Could be cheaper to build a new tank from stainless,I removed the auxiliary tank from my MCI and patched it washed the inside
I did it like most oil field welders do ran a pipe from the exhaust on the car to the inside the tank for 10 minutes then welded the sucker no oxygen in the tank no boom OHSA approved I don't think so but it works ;D
Consider yourself lucky you have a tank that can be patched the newer Prevost have a plastic tank no patching those big $$$$ suckers
It's a diesel tank. If it were rinsed, it wouldn't blow up on you. Not sure it's necessary to say "not the smartest thing to do". If it were a gasoline tank, the impetus to rinse the tank well would be even more important, but as for the diesel fuel soaking into the aluminum, I would definitely research proper cleaning at least for that particular spot/area. But shouldn't be a dramatically dangerous or difficult job for someone good with aluminum.
Thanks for all the feedback everyone.
Muldooonman - I am in Minnesota - south and west of Minneapolis by about 1h 30m. So - now I need to find me someone in the area who is comfortable (and trained/experienced) in this type of repair. I don't intend to do it myself since I don't weld aluminum.
As far as the rest of the bottom of the tank it is in excellent shape. Whatever caused this problem was not "rubbing". It was some sort of galvanic corrosion as the aluminum was clearly "eaten" away in this spot. Interestingly, it was corroded from the outside in.
Clifford - I'm definitely glad this is an aluminum tank and not plastic!
Thanks for the location Brian. Started to say if you where down Texas way I would do it for you. Replace the whole bottom with a overlay. Good luck.
Scott B. don't be fooled diesel vapor is still present after "rinsing".... You would actually be safer to weld a steel tank that was full of diesel than not.
I am like clifford, oilfield gitterdun, "or we'll get someone who will"... I won't go into detail, but I'm still here to talk about it LOL :)
When I working for Tennessee Gas all our final tie in on the natural gas lines were done with natural gas flowing through the pipe if you had no flame you waited till the gas would flame before welding. lol it takes you a while to go around a 36 in pipe.
Has nothing to with welding a fuel tank but it can get interesting if the fire goes out while you are welding, so welding on a fuel tank never worried me I have repaired many of storage tanks before full of diesel by welding, they never drain those tanks to repair a leak fwiw
Brian,
I pulled my tank and had it welded right in town. We have a shop that does aluminum welding and builds and repairs tanks. Throw it in the pickup or on a trailer and bring it up. They're right in Watertown. But I'm sure you can find somebody down there too.
Fred
Quote from: luvrbus on May 17, 2015, 07:27:49 PM
I have repaired many of storage tanks before full of diesel by welding, they never drain those tanks to repair a leak fwiw
yup...pretty hard to find a place to put 1000's of gallons when a tank is leaking...
Like clifford said about high pressure npg lines, welded a few hot taps myself back in the day while pipelining. Nothing like welding on a line flowing 3 or 4 thousand pounds of nautral gas pressure. Kinda makes you pucker up a little.
Kinda makes you wonder about the first guy that ever thought about doing that/had the balls to try it, doesn't it.
Run a nitrogen line and weld it. The best thing is to pull it out, take it to a shop and have them rebuild that thing out of stainless. Never again will you have to discuss this problem.
One thing you can do if you weld on it is hook up a hose to your car exhaust, start the car, have a cold one and then it should be safe to weld on as carbon Dixon will not ignite. Had a welding shop do that on a motorcycle gas tank for me. On my MCI I took it to a radiator shop and they did it for me.
ED
Hi Brian,
Us Coach sent my tank out for repairs back in 2007' and so far it's been holding up well. What a stinker when it
leaked into the blower compartment and it took a year for all the diesel smell to go away!
Another thought could be fiber glassing the tank. Maybe pour a whole gallon inside and fiber coat the outside.
Good Luck
Nick-
As mentioned before, although welding a plate to the whole bottom of the tank would be an excellent way to go, I wanted to defend the JB Weld concept also. Considering that the fuel in a full 100 gallon tank would weigh about 800 pounds and that the tank bottom is probably over 1600 square inches, the pressure stress on a small hole is really rather small. Wouldn't it be around 1/2 psi?
If one were to take a 4 or 5 inch square piece of aluminum, clean everything well, and use the epoxy to seal and thoroughly adhere it over the damage, do you think that it would not hold for a goodly amount of time? It could even be supported from below. A gas tank I once sealed with it was still fine when I sold the vehicle 10 years later. Of course, I do not know if it would have been that way if it had to endure extreme temperatures. It may or may not.
I am not saying this is the best way to do it, merely that it is a workable way if one did not want to remove that tank and was looking to get away cheap.
I would recommend a different two-part epoxy - MarineTex. My diesel tank started seeping from where I had tapped into the top side for my Gen feed and return. I called the MT manufacturer and the CS rep said as long as the area was abraded and thoroughly cleaned of diesel fuel the product would hold. That was 8 years ago - no problems. YMMV.
Mike in GA
I was able to bring the tank in today and the shop was able to easily weld a patch on the bottom. I'll try and get a picture posted the next day or two of the patch. $132 for the 2 hours of labor and material. not bad! I called caylor supply on a suggestion from the shop and he wanted $300 for a used tank and $200 for shipping.
I cleaned up the fuel tank compartment and the fuel tank last night. Tonight I cut a piece of HDPM (roofing rubber) to replace the old disintegrated plywood. I have the fuel tank partially loaded into the compartment and filled with some diesel. I'll let that sit overnight and check tomorrow night to make sure the patch is not leaking.
Nice shinny patch and sort of clean fuel compartment pictures...
Eagle and Cliff, your stories of welding gas lines and storage tanks made me pucker. That's just nuts. If a tank is steam purged I would think that the vapor ignition hazard is nil? No?
Nice work Brian. I'm looking at that compartment and thinking to myself "bummer a fuel tank has to go there. Could really use the extra storage space" lol.
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Scott, NEVER EVER EVER trust an empty tank. I don't care if it has been steamed for a week....
IF it is filled with any displacement that is not liquid YOU MUST TEST THE INSIDE SPACE WITH AN EXPLOSION METER/SNIFFER PERIOD.
The scary ones for me were the interior baffles in OTR fuel tankers....
When I worked for the Air Force (as a civilian) it took a committee to get approvals :)
I do not trust exhaust. especially from a gasoline engine.
IF there is no vapor there cannot be an explosion. Explosions will kill you fires will burn you.
Simple physics....it takes a combustible fuel air mixture and a spark to make a piston move...in fact an EXPLOSION confined in a space. LIQUIDS do not explode.
I have been watching the 6 o'clock news every nite and I never saw where Brian's tank blew up and took the state of Minnesota with it so I guess it went well
Quote from: luvrbus on May 22, 2015, 05:41:17 PM
I have been watching the 6 o'clock news every nite and I never saw where Brian's tank blew up and took the state of Minnesota with it so I guess it went well
Well I would venture to say...
in the tank welding game....you are very lucky if you get a chance to make a second mistake :)
Right - no explosions. That is a good thing. I have now had 120 gallons in the tank for over 40 hours and no leaks. Looking good!