Our fuel tank has a hairline crack in it and is leaking fuel, the weld shop wants to fill the tank with water to weld on it but that doesn't sound like a good idea to me. With the baffles and piping inside the fuel tank I don't know how we could get all of the water out afterwards. I'm hoping get some insight on the subject, if anyone has experience with this I'd like to hear about it. Thanks in advance.
Tyler
When I was in the Operating Engineers as a Heavy Equipment mechanic, we put dry ice in almost full fuel tanks waited 10 minutes then capped the tank and stick welded the cracks on the outside. I am sure OSHA was not informed of this practice. Lots of tanks cracked on scrapers and bulldozers. With my crane I used a JB weld product made especially for gas and diesel repair. Didn't want to press my luck on the dry ice any more.
The JB Weld stuff for tank repair works fairly good.......might be worth a try.
I was recommended a fuel tank patch kit from napa that I'm going to pick up and try.
If we have it welded, How do we get all of the water out if they fill it up?
I have welded fuel tanks before and I like to do it on a cool day. If they fill it with water, where it is being welded should be free of
water as the water will cool the weld to quickly which weakens the weld. Getting the water out shouldn't be a problem.
Drain the tank after welding, then turn it upside down. Let it sit for an hour on a warm day and it will be dry. If its not warm enough use a heat gun.
Turning it upside down means you don't have to worry about baffles and the water will drain out of the fill holes (one at each end), and the generator and engine hose connections.
My dad always filled up gas tanks before welding back in the 50's, then took an acetylene torch to the fill hole to ensure there was no fume buildup...
Alcohol. A couple of rinses, maybe three and push it through all the outlets with a little air pressure. Water all gone.
Dry ice? Excellent idea. Make the cap the high spot and when the CO2 pouring out extinguishes a flame you're ready to weld. The shielding gas is for welding aluminum is argon and if tank were full of argon there's nothing to support combustion.
Water? BTDT after washing with detergent and triple rinsing the tank with water. The fill with water everywhere but where the heat needs to be. There may be a whoosh but it'll be a small one.
I had a cracked tank in our previous coach. JB Weld didn't work. Fancy aircraft fuel tank sealer didn't work. I removed the tank and took it to a shop. They welded a patch over the leaking area, and did not say anything about filling the tank with water.
Wouldn't a small amount of water just be separated by the water-separating filter?
If I were worried, I would put the hose on my shop vac on the air outlet, tape it on to the fuel neck, remove the level sender, and let it run for a few hours.
Fill the tank with water leaving the area to be welded above the water. Put a little dry ice in and after a few minutes, weld it. Dump the water followed by Matt B's advise with the shop vac/fuel sender method. Good to have the sun shining on the tank while drying it.
Pierce
Tyler, You may want to take a look at this:
https://www.amazon.com/Versachem-90180-Heavy-Duty-Fuel-Repair/dp/B002N5JAO2?th=1
I used it about 18 months ago on my Skid Steer tank(diesel) and its been holding strong ever since.
I don't know if we're going to be able to find anyone close by that is going to purge the tank with argon like I would prefer. I'm going to call another place tomorrow and see how they would go about welding it, but if they are going to fill it with water as well then that might be the way it has to get done. Although I don't really like the idea of filling our fuel tank with water, that is the most common solution I've heard from talking with people. There are pros and cons to any method it sounds like and if the residual water isn't a major issue to most people, then maybe I'm worrying about it unnecessarily.
What about fastening one of those cheap heat guns from Harbor Freight to blow heat into the tank?
Cheap enough when on sale at about $9.95
A qualified repairman is going to use argon gas to shield the weld, it's part of the GTAW, Gas Tungsten Arc Welding process. Also known as TIG welding, and when used on aluminum HeliArc sometimes with a mixture of Argon and Helium as the shielding gas.
Besides, you can also use a CO2 fire extinguisher to purge the tank of oxygen.
There's probably a lot of different ways to purge the tank, but finding a welder here in the area that is going to use those methods might be a challenge. I've read and been told that running a hose from the exhaust pipe on a vehicle into the tank will also work well to purge it, but again, I don't know if I'm going to find anyone that will do that. I would much prefer someone to properly TIG weld the tank but haven't found anyone that can do it.
I would mig weld it.
After they fill the tank they weld it up then they pressure test it.. If all is well they put it in the oven to get the water out .. depending on whats inside the tank as fillers.. some have foam and others do not.. They call it burning the water off or out.
Oldguy is correct, it can be GMAW aka MIG welded, but at the end of the day you need a qualified aluminum welder, not a guy with a torch and some cadmium rods. And all aluminum welders will use a shielding gas.
For getting the water out, alcohol mixes with water so the resulting liquid evaporates much quicker than water alone.
So if the the crack is in a corner it is very likely to re-crack again in the future. I last month built a 30 gallon aux tank for my diesel truck I left the top cap off and internally welded all the lower internal welds. Truck is much harder on weld corners than than your coach. Many more "G" forces while driving. Crack needs to have almost all material removed opening up a V that is to be filled. Do not let them use 4043 , should be 5356 filler. Tig repair or Mig is purely up to what the welder is set up to do. Let him judge what he prefers. I generally Tig for repairs and Mig for initial production. Argon filling is preferred, but washing with soap, water and forced air during welding is fine. No possible way to weld properly full of water in my world. May be doable but I've never attempted
Scott
It attaches really well with water and can be poured out. I use distilled water to remove the alcohol out of fuel. Pour it it, shake it up, let it separate and drain off bottom. Alcohol free fuel. Doesn't get rotten as fast.
Scott
Got a phone call from the weld shop saying they're not interested in doing the repair due to the risk involved. Apparently the last tank they did, some 20 years ago, they blew up and don't want to do another one even if it's filled with water. I don't know how many people we've had do that to us, say they can or will do something and then call later, or not at all, and say they didn't want to do the work...
Wash the tank with soap and water. Blow out, let it sit inthe sun , .
Fill 96% with water, leaving the welding area high and dry. Leave the tank open vented so that the remaining fumes wont explode the tank further.
Drill the crack ends, V grind the problem area, weld as required.
Empty tank , blow out , run hair dryer into filler neck for an hour or so.
Is it that difficult to weld a tank that has held diesel fuel? You know how hard it is to get it to burn let alone explode? Or maybe I'm off my rocker.
Welded, GAS tank used argon to purge tank-- don't trust the label on the argon tank put paper towels in a bucket light them then turn the argon into the bucket, if fire goes out you are good if not find another bottle. One tank labelled argon turned out to be oxygen--would have made for a bad day.
We don't use MIG we use TIG each to their own
Chris
Go down to Wally world and get a jug of the cheapest cooking oil, pour it into the tank, swirl. Weld tank. done. If you're lucky it'll smell like french fries:).
We know that when air is compressed, it gains heat and then the diesel explodes when injected. With the heat of an arc, any vapors inside the tank may explode. Sort of like a grain elevator. If a tank exploded when empty with someone next to it, the results could be tragic. Diesel is tough to light on fire when cold but changes character when heated.
Here is a good but short read on the dangers of diesel vapors when the temperature of the liquid exceeds 100 degrees: LCO-47: Diesel Fuel Vapor Hazards (https://forestresources.org/digital-magazine/item/329-diesel-fuel-vapor-hazards)
We all remember TWA flight 800 where the vapor exploded. Jet A is not much different than the fuel we use. In fact, our coaches would run just fine on it.
Pierce
We have dealt with this issue with marine fuel tanks, many times. One of the challenges is the fact that it will need to be TIG welded. In order to achieve a non porous weld it will be necessay to eliminate any hydrocarbon contamination on top of, or on back side of the weld. Typically that means removing the tank, emptying it, pressure washing it, gotta be clean clean clean. Then the crack can be ground out and a Tig weld done.
You might want to check out one of the epoxy or polymer based patches others have recommended. There is some good stuff of that sort available these days.
Shoe Goo?? Just kidding!!
A proper purge is easy and quick. I have tig welded
many fuel tanks. I always purge with argon on aluminum tanks and welded. No water or other exotic method... just a good argon purge with the openings taped off except one for the argon to exit.
Welding aluminum the aluminum must be clean and use a stainless wire brush, I learned that the hard way.
We found a welder down by Alamogordo that is going to TIG weld the tank for us. He said that he's TIG welded diesel fuel tanks since the early 80's and that he was not worried about welding the tank as-is, without filling with water or purging the fumes. Who knows... hahaha. The crack is in the weld, a little less than halfway up the tank and is about 4" long. The guy is going to grind out the weld along the crack and re-weld that area. Then he is going to cap that area with a piece of aluminum angle and then weld completely around that. Then he is going to pressure test the tank. He sounded knowledgeable and his outfit looked legitimate, so we're keeping our fingers crossed.
Congratulations! The tank can be replaced, but it's less expensive to repair it properly.
FWIW an ESAB MiniArc Rogue is $800 less the gas. Then you still need to invest the time and materials to learn how to weld aluminum, and develop the skill to so do. I bet the professional comes in at less than that expense.
The Miniarc Rogue provides a smooth DC (Direct Current) welding power which allows you to weld a variety of metals, such as alloyed and non alloyed steel, stainless steel, and cast iron.
Doesn't mention aluminum. Need ac for tig aluminum and dc- for mig. New millermatic 255 I purchased will mig alum but not tig aluminum. Still keeping my old syncrowave. But it did cost more than $800. Smallest aluminum machine sold with "pulse" capability. $3300 and with the push-pull gun your up to $5500. Paying for the repair will be much , much less.
Scott
I would love to be able to weld aluminum and make a slick stand like yours in the photo. Attached is my old Millermatic 35. I bought it when they first came out and it welded almost 24/7 from that day on. I do have an argon tank and use it with .023 wire for the thin stuff but mostly .035 for the DOT work and general welding. Argon does make a little flatter bead. It has worked flawlessly from the day I bought it. Think Miller invented it for the 1965 Mustang.
Wish I could add on to it for aluminum.
I was fortunate that two of the guys I worked with were ex-shipyard welders so they took to it like a duck to water. They quickly learned to make nicer looking beads than I could.
Terrific job on the stand!
Pierce
Your mail box is full again. Stop by and I'll teach you how to use and set it up in under a hour. World is changing
Scott
This is the machine I used to heliarc ski boat tanks in the early 80's Haven't used it in 30 years now. Have helium, argon and co2 tanks. Really messed up the dw's tv when I used HF.
Scott and Chuck,
Deleted the letter bombs from the mailbox. Good thing they can't explode or I would look like Wiley Coyote after a run in with Roadrunner. :D
Chuck, I have deep seated envy after your garage motorcycle photos. I want!
Pierce
My bad. But the excuse I offer is that the ESAB is the minimum equipment I need to repair the gas tank and weld in patch panels on the Siata -- If I can't find someone local to do it for less. At work I had a Miller with a spool gun, and avoided aluminum welding as much as I could. Steel is more forgiving.
My 40 yr old Miller quit last month. About 150@# of stuff inside . Welded pretty nice. Screwed around dioging it for about 3 hrs. I get 80$ per hr.. No easy fix, looks to be the control board maybe.
Go online for medium power Mig welder. They all are about the same specs at 190 amp /65% duty . etc. Inverter powered , no big transformer. The Miller( Chinese parts) is about 900$ and the E bay Chinese ones are 300$ ish. Same power supply it looks like .
I bought a well regarded 340$ unit. Sun Power 190. The weight is about 30# . the accessories are junk , but swapping some cables a round it works nice. Welds better than the Miller ever did.
We have a miller 211 with a spool gun that welds aluminum really well. Pierce I found welding aluminum was easy to learn, give
it a go.
Thank you to everyone for the tips. Appreciated. I have gotten fairly good at powder coating now but only after chasing my tail for a while. So, anyone interested, drop me a line.
Pierce
We got the fuel tank back yesterday and we are very satisfied with the work. The welder said that once he put some heat to the crack it really opened up and was quite a bit bigger than we had thought. He repaired the crack and then capped over the entire area with a piece of angle. The cost was only $106.31 and we didn't have to mess with any water in the tank. The other place quoted me a base price of $175 for a MIG job and a tank full of water. I'd say this project was a win win!
We got the tank reinstalled today and after priming the fuel system, Pearl fired up without a hiccup. ^.^d
Congratulations on your successful repair.
Some of the aluminum fuel tanks in our old coaches are approaching 40 years old. I wonder how many have suffered a mechanical failure. Based on my reading from the time I have spent on the Forum, I would guess not too many. Also wonder if there is any common factor to account for cracks or leaks in some of the tanks. Probably high mileage would figure in, since pretty much everything in the chassis gets shook up pretty good going down the road. Was there a human component? Perhaps one welder at the tank factory was less skilled, or hung over on Mondays?
Just idle Sunday morning musings...
glad to hear everything went well
I like
Scott
Looking at the pictures, it appears to me that the fabricator didn't get the weld balanced between the top and the side More of a weld separation than crack.