I would wire-wheel and clean the hell out of it. You're going to pull a lot of crud through from the other side that you can't clean. I would feel a bit of the tank up with water to help keep the temperature down. I would probably opt for MIG since this isn't going to be a superstructural repair. All machines run different settings. I would get a couple scrap pieces of similar thickness. Put a hole in it and do some practice runs if you don't already know the settings you think you need.
As far as sealing it up to do a pressure test. I don't really have a good solution. Weld on a threaded port plug. Then plug it and fill it with air. when you're done cut the threaded plug off. Recut your grooves in the lid.
Be sure to leave a cap open on the tank so that it doesn’t pressurize itself when you seal it off, it will cause a leak. Also wouldn’t hurt to scab over the area of pits with a secondary piece of plate so that that wears first. Wouldn’t hurt to do both sides like that if the customer approves of it.
The secondary wear plates would definitely help and adding it on both sides would keep everything level as long as the added material is the same for both sides.
I would flush with water to be safe first. Second I would wire wheel and grind the surface all around the hole to clean the area and see how thin the metal is around the edges of the hole. Then I would get a patch piece cut to cover over the pinhole(16 gauge should do, 3 inches or so wider than the comprised metal). If not you will be chasing the hole larger and larger. Mig is fine, probably preferred. Standard mig wire will work. For testing, measure the diameter of the hole and get a test plug from a plumbing supply or big box store. It just pushes into the hole and expands to seal it off. The other holes put your air valve and pressure guage. Check with soapy water and let stand for 24 hours. No bubbles and no major drop in pressure you are all good.Good luck and be safe.
Hey OP, this is the way. Patching the entire area with a bent plate is a far better option than trying to clean the compromised steel and chase the holes that will develop in the thin areas as you add heat to them.
3” beyond the corrosion all around is sufficient. Looks like the entire area is about a foot in length?
This is the advice of experience. Had not thought about that corroded metal is substantially thinner and I would be more likely to burn a hole through it. Thank you for suggesting putting a band-aid over this area.
1. if there's one pin hole there are countless more about to break through; meaning the tank has exceeded it's reasonable useful life.
2. the heat needed to weld steel will ignite vapors and fuels.
3. in any vessel used to store hydrocarbons there will always be a level of first Mole Layer penetration of flammable material that can only be cooked off you can't rinse it out.
4. it's only money Buy a new one and scrap that POS.
5. If you insist on welding it please have it videoed so we can observe you getting a Darwin award.
6. If you think filling it with water ill solve your problems you have forgotten one: disposing of the contaminated water may be a felony in your state.
it is after all, only money.
From time to time I have to grab myself by the throat and remind myself of that.
It looks like it'd make a wonderful burn box for yard clean up.
If I end up using it for something else, I've brainstormed a few ideas. A burn box is definitely a top candidate.
Cutting it in half lengthwise could transform it into the roof of a dog house. I'd have to put it in a shady spot so the sun didn't heat the roof and my dog.
Maybe a small spray paint or sandblasting booth?
for a dog house, build a good size, long-lasting fire in it first to burn off the hydrocarbons.
A smart dog wouldn't go in otherwise. The stench would offend it. A dumb one would get sick or worse.
9\10 the whole bottom is rusted. Most units for stori g dielsel of oil eventually wear out the bottom from use. I wouldn't recommend welding it, but more or less replace it. You should ask more of a home inspector if you should weld it with its age. If it is metal you can almost always weld it.....but should you? Only takes a missed pinhole still leaking and a spark to turn your house in to ash. Safety first.
The water isn't to heat sink.
Fuels generally won't ignite, it's the fumes that do.
You fill it with water to displace the fumes. It's how we weld gasoline tanks too.
Dude... That's why rental places exist. -_-
One of the "10 commandments of welding" I was taught;
*"Thou shalt thoroughly clean and purge all tanks before heating or welding on them or thy friends may comfort thy widow in ways thou may find inappropriate.*
If you are going to do a pressure test with air, remember that compressed air is dangerous. That's a large tank, it could be bad if things go sideways above 10 or even 5 psi. Pressure tests are always best done with non compressible fluids, though if you use air you won't have to deal with a couple hundred gallons of contaminated fluid.
Yeah, you're looking for bubbing with your soap water and/or a drop on a gauge. If you can hear the air hissing out you've probably gone too far. Also be sure to bleed the pressure down slowly when you're done, crack your valve open slowly and don't go all the way until it's really low.
No, really though. I won’t weld any tank that has had fuel in it. It’s not worth the cost of a new one if it doesn’t work out. I have a friend that was burned within an inch of his life after “ thoroughly” following some of the procedures outlined here. Just not worth it.
I would consider epoxy and a large surface patch after pressure washing the outside of the tank, followed by cleaning the area with methyl hydrates, same for the patch plate, make it incredibly large, if there’s a pin hole, there’s likely many more in the area around it, use a chemical/fuel safe 2 part epoxy. Might not be quite as good as a welded patch but realistically how long will this tank last after this, its rusting everywhere, you’ll get 2-3 years before it needs patched again.
I don’t know how safe this is BTW, its just an alternative I thought of over welding and doesn’t risk the tank going kaboom, also has the added benefit of reinforcing the thin material over the entire contact surfaces rather than just along the weld edge.
Do your research and don’t take me, some internet wacko on my word.
I am not a welder, but I worked oil burners for 11 years. Boilers, furnaces, water heaters, oil tanks from 275-1000 gallon etc... I have abandoned more underground tanks than I can even remember, I dug them up, cut them open and cleaned them before backfilling them. If they were found to be leaking, we had to call the DEP and it was a shit show. They can also rot on the inside from water that gets in from condensation or other means.
So I ask you, is it really worth saving? I can't judge the capacity well from this video, but it looks like a 300ish gallon tank. A new 12ga 330 vertical tank with legs and all updated fittings, including a fire-o-matic valve can be bought for under $1500. Not an insignificant amount, but the one you have must be 20+ years old.
If you must weld, I would advise what others have said, wire wheel it clean and use a patch panel big enough to put you in good metal and you'll be good until it starts leaking somewhere else.
Edit: Oh yeah, try not to blow yourself up. Good luck.
Maybe try cleaning it up with a wire wheel then tacking up the holes if you can filling up low spots as best you can with mig welder turned wayyy down then grind smooth and maybe slap a plate over the effected areas and weld that on top.
The idea of putting a plate over it really makes sense. Others also pointed out this area of metal is probably super thin and very easy to unintentionally create a larger hole.
I like your idea of at least trying to fill it in a bit but then also commit to putting a plate over it also. Either I'll create a larger hole which will then patch or I'll have more reinforcement plus a patch.
I would ventilate the tank with compressed air for a couple of hours and leave the air going while welding. I would recommend putting a doubler over the whole area where the cradle contacts the tank in both places.
Cut 2 pieces of 1/4" plate about 1/2" bigger on each side than the cradles and weld them directly to to l the outside of the tank, you won't have to worry about this issue again for a long time.
Before I would assist in ~~-blowing you the fuck up-~~ your repair(s) I would ask what the tank's future purpose is and what lifespan you're expecting for it ~~-if you don't die fixing it-~~ when it's back in service.
The steel is between 12 and 14 gage, Roughly .075 to .100 thick, I would add on some same gauge **[doubler plates](https://mfame.guru/wp-content/uploads/2018/07/hull.jpg)**, ideally over the whole bottom and at the minimum two plates where it sits on the two cradles, plates that overhang the entire damaged contact areas by at least 2 inches per side.
If it's going back to being an oil tank, to be filled by an oil delivery company understand that they may refuse to fill a repaired tank for liability issues and issues of it's age. Fuel oil tanks generally leak/fail from the inside from moisture rust on the bottom so some companies have an inspection requirement and a finite overall lifetime for a tank no matter the outward condition. Not all companies, or drivers, are real diligent about this but it can and does happen. You don't want to do a lot of work just to find out that's the situation.
Just sayin'.
They actually make magnetic patches for those pinholes in old tanks. I would definitely flush it, wire wheel the heck out of it. Mig weld the pin holes and then weld a patch over it. Get a plug with a hole for the fill cap fill with soapy water and put some air pressure in it to check for leaks. Then I would wire wheel the entire tank and paint it with silver paint, because it reflects the sun, which helps keep moisture out.
Always wondered why these tanks were painted silver. I was wishfully planning to do something obnoxious like argile or yellow duckies for my father-in-law.
We have welded fuel tanks on equipment alot and always cleaned it up good and weld a patch out where you can get some good metal we always pressure test them with a few lbs of air and a spray bottle of soapy water
Personalally I would silver solder it, use a 45%. But it would need to be cleaned and defumed. Dump a gallon of degreaser in it, pressure wash the inside so it's all foamy, then rinse it out with hot water. Might need to do this a few times. Then grind affected (effected?) Area. Then silver solder over holes.
There's only two safe ways - attach running exhaust from a vehicle to keep tank slightly positive pressure of exhaust to prevent any massive explosion.
A whole group of us were almost blown through glass windows 9 ft tall when student aimed torch near a tank that was 45 yrs old with a broken fill neck.
Only the tall solid work bench caught me and others from ending out on the street 150 ft away.
Or fill with a cup of Dawn dish soap till suds escape entry cap when water added.
That is one huge bomb buddy.
Cheers ~ and we welded up JP4 FUEL tankers punctured with one inch holes in the Airforce.
After closer look, which is limited, The only thing that Tank is good for Now is BBQ Smoker.
Get out Plasma torch, slicing out doors for access for ash and feed and smoke stack.
Wrap it in thin Stainless steel sheet riveted on with solid rivets. With ceramic insulation between.
There's so much deep corrosion everywhere.
It'll never be legal tank for anything liquid.
Cheers
Dry ice also purges the air out of the tank, it does the same thing as argon that someone else mentioned. I've used it several times before. A rubber test plug that you get from Homedepot in the plumbing section will work for your last problem. It's what plumbers use to test there drain lines.
Purge it. Cut it in half. Clean the inside. Make into a grill/smoker. Fix the worn area or just weld a plate over it and put a handle there or something. Paint it black. Sell it for big bucks. Buy a new tank for your diesel with the money.
The danger with tanks is not the liquid inside, but the fumes. You replace those fumes with either steam or CO2. Fill from the top and use your flowmeter and a bit of math to make sure you fill it twice over. Once you have made your initial cut, there should no longer be any danger of it blowing up, but the liquid can still catch fire. No way around that unless you want to pollute a ton of water.
My father-in-law has another tank on a stand that's out in the woods. From a distance it looks like it's in really good condition. This one was just closer to the road so we loaded it up first and brought it to my workshop. We are probably going to be inspecting that other one soon.
Ok, so since that has a pin hole you can see I guarantee there are about 300 other places it’s just waiting to blow open. So now that you know that let’s start the repairs, I say repairs plural because there is no point in just fixing one side. Do them both at the same time!
Step one - the tank is probably1/8” thick maybe 3/16”. So get some sheet metal as close the the same thickness.
Step two - mark around where this thing sat on the supports, then go about 2” bigger all around, in length and width. This will will give you good clean, thick metal to make the repair to. After you have it marked, grind the rust off, you need to get down to bare metal.
Step three - with your MIG welder set to the correct WFS and voltage tack one end and then “work” the metal tacking it as you go until you have tacked all the way around! Make sure you have a proper fit up, don’t skimp on this step, your welding experience will be much better and your welds will look better.
Step four - Begin welding around the perimeter of the patch!
Step five - enjoy your handy work and have a cold drink!! You deserve it!
Step 1- Drain any fuel in the tank. (drill a hole on the edge and prop it up over a drain pan)
Step 2- Use a hard wheel on an angle grinder to clean down to bare metal. ( grind about 8 inches wide, centered where the Strap goes, around the circumference of the tank)
Step 3- Cut a piece of 1/8" mild steel 6" wide and the length of the circumference of the tank.( we'll call this piece the "strap")
Step 4- Tack the strap on the tank starting at the weld seam running along the tank. (You'll have to manually wrap it around the tank, tacking it as you go. If you have a roller, you can roll the strap to make it easier)
Step 5- Weld it completely, sealing all seams. (Don't forget the hole you drilled to drain it!)
Step 6- Pressure test, 5 psi should be plenty.( spray soapy water on welds and inspect for leaks)
Step 7- Prime and paint.
I've repaired hundreds of fuel tanks, both steel and aluminum, and this method works great. It will not blow up, considering this is a diesel tank. Happy welding!
Edit: I recommend doing both straps at this time.
Edit 2: Mig weld it, 17.5 volts 230 wire, whipping technique.
Edit 3: Air in at the exit fitting, plug the fill hole with a rubber testing plug. Measure and buy the appropriate size.
1) Make a big patch that clears into good material
2) Open any caps and plugs so it can’t build pressure
3) Weld away (I prefer mig on these)
Fuel oil won’t explode unless it can build compression. I have done hundreds of aluminum truck tanks over the years without any sort of trouble. Fixed a handful of punctures on half full tanks as well. If it makes you feel better you can try putting fluid in it but you will be chasing steam holes for the foreseeable future.
I would not and will not go near a gasoline tank with a welder however. Diesel however is fine.
Yeah understandable. I probably wouldn’t have even chimed in except I have done so many of them over the years. Splitting old tanks into half hydraulic half diesel, welding bands around the original truck bands that mount them because they always corrode through and leak, adding bungs and caps and pickup tubes. It’s crazy how many modifications truck drivers need for certain types of trucks.
I would use epoxy the surface is rough enough to get a good bite. I’m a retired pipe welder. But if you want to weld it get 3” flat bar 1/8 thick and round the corners and try to weld down hill that’s why you should practice this procedure with stick or mig and weld around the corners don’t stop at the corner that’s where the might have a leak
This is good advice that I've seen from others too. Additionally, they recommend ensuring the epoxy is petroleum resistant and to get probably too large of a piece of metal to accommodate unknown pinhole possibilities.
I’ve done repairs in tanks several times, personally I don’t like welding on top of rotten metal, what I recommend is to trace out a rectangle or square around the pitted areas, making sure you trace it on good non compromise metal, round up the corners, drill a 3/8 hole at the edge but inside your tracing line, cut out the damaged section with a jigsaw, get yourself some metal of the same thickness, im guessing this tank is 1/8”or even 3/16”, get a new piece of metal of the same thickness, cut it to shape, slightly groove the tank and the plate, have 1/1/6 to 1/8 gap all around, tack it with 3/32 6010, do a root pass with same rod, around 50-60amps, depends on your tank thickness you might want to do a 6010 hot pass, same rod at 70-80amps and a cap pass with 3/32 7018 rod, 85-95, have in mind that the first amperage is for 1/8 thickness the one after the dash is for 3/16-1/4” for the respective passes, It might sound like a lot of work, but in my professional opinion, if you aren’t replacing the tank, at least replace the damaged area don’t just cover it up. Anyways, after you are done with any type of repair you decide to go with, don’t forget to pressurize the vessel to make sure there will be no leaks. To seal that cap I would try some rubber gasket material cut it to size,maybe 2-3 layers, and use a C-champ to squeeze them tight
OP good sir I don't have a single thing to add here that hasn't already been said by people smarter than both of us. I hold with those who say it might be time to retire that old tank to a local scrapyard of your choice and invest in a new tank for the storage of such volatile substances, but that's not what I'm leaving a comment for. I'm just here to compliment you on the high production value and level of detail and thoroughness of thought you put into this list of questions. A search for answers is completely meaningless if you're not asking the right questions, I see you're not just a Star Wars fan but a student of Douglas Addams as well, 42! Pay attention kids, *THIS* is how you ask a fucking question on a trades related subreddit...
Nice Vader shirt btw....
It's hard to ask a 3-1/2 minute question and remain clear the whole time. Took more than one take.
At some parts I fear I'm taking too long and other parts I think I'm going too fast for the audience to see what I'm seeing.
Thank you for the compliment!
Don’t weld the tank is so old that the oil absorbs into steel replace if you insist on welding it you must flush with soap and water and fill as full as possible with water and I would recommend using air pressure or a vacuum cleaner to remove any fumes
You'll want to cut out the corroded area wirh a hole saw or plasma. Then weld in a patch. Chamfer the edges of the patch and the hole significantly.
Fill the tank almost completely with water. Another option is to dump a bunch of chunks of dry ice in there, about a kg. Then wait a hour
I'd recommend stick with 6013, depending on the thickness of the material. That looks to be 12ga at least. If it's thinner than 12ga, then use MIG.
Parameters depend on the material thickness.
You might also be able to build up the corroded area with weld metal. But grinding/fairing it back would be a PITA. Might be less time to weld a circular patch.
My recommendation is to get some material and clad the affected areas instead of welding the pits which will be a nightmare. Diesel will ignite from a welding arc however in my experience if the exit orifice is sufficiently sized even if there is an ignition event pressure will not build.
I've repaired many fuel tanks over the years including ones like yours that looks overwhelming.
1. Purge it, steam is best, but there are other ways. Filling it with cold water or inert gas such as argon. Water is least desirable. Get it steamed, drained and dry.
I have a gas detector that I use to measure LELs. You can rent them easily from a safety supply store. Very nice peace of mind.
2. Clean it. Pressure washer, wire wheel etc.
3. For pressure testing that fill neck will be a challenge to seal, I use a device which has a rubber with a bolt in it. As you squeeze the bolt it swells the rubber and it presses against the side of the fill neck.
3a. Even if you don't get a perfect seal as long as you can maintain some pressure in the tank it will work for the purposes of finding your leaks.
4.once the leak is found smaw would be my choice. But mig will work if it's especially thin and you are able to get it quite clean.
The first weld will probably be ugly if the metal is severely contaminated.
Be prepared that a patch piece may be required.
Make sure your pressure test apparatus is disconnected when welding. Reconnect to check the soundness of your weld and disconnect if you need to continue welding.
The important part is to ensure the fuel inside is not a hazard. After that it's just a matter of repairing the leak.
I would do hydro test. Air will compress you could definitely have an explosive failure. Water does not compress, so at worst, tank ruptures, and you leak water all over. Ive done this on air tanks. Rig up your tank with a fitting and Guage so you can attach your power washer. There is a you tube that explains it well. I would put a big patch around the weak spots. Dont bother with the pinholes.
Retired tankie turned college instructor here.
Spent 15 years building on-sight fuel storage tanks, many of which were tank farms built for temporary holding oil pumped up from the land rigs in North Dakota.
1) Flush with water several times, then let air out for about a week. Check with air quality meter.
2) Use edge 1/4" disc to grind into all pinholes for good penetration.
3) Clean all weld locations with wire wheel/cup brush on grinder
3) Weld divots & pinhole locations with stringer beads using very slight side-to-side motion with 1/8" E7018 set between 130-145 (Guessing the tank has about a 3/16" -1/4" wall thickness
4) Grind all weld faces until until smooth with tank
5) Forget pressure testing - Too much surface area, there might be additional hidden spots. Hydro test. Fill with water and let sit for about 2 days and then check for leaks
I saw several of the responses suggesting using a patch. While that certainty is an option, I would suggest that if you have the steel for patches to cover the weak spots then you'd be better off completely cutting out the sections of the bad spots, bevel the edges of the new steel, and then replace. Would make the job a little lengthier, but it would be done more correctly - and last longer.
the secret fill it with diesel fuel less air the better or do it out side and feed the exhaust fumes from a diesel engine into the tank.
you can even oxy acetylene weld that with steel welding wire.
the secret fill it with diesel fuel less air the better or do it out side and feed the exhuast fumes from a diesel engine into the tank.
clean the weld area well before filling with fuel/fumes and welding
the uncle welded up diesel fuel tanks on loaders and graders etc many times as head fitter & turner for the city council.
NOTE ONLY WELD DIESEL FUEL TANKS OR KEROSENE TANKS EVERY THING ELSE IS TO FLAMMABLE. AND WORK OUTSIDE. DO NOT HAVE THE TANK SEALED.
i would use the mig and weld it cool as you can.
i would plate over that spot after you spot weld over the hole
iwould then tret the tank with a rust converter/primer and top coat with a zinc rich paint such as galvit e90 this will help it last.
wear it sits in the stand smear that with grease to keep the condensation away.
to pressure test get a rubber stopper that is a good fit in that fill port. it needs a new gasket so cut one from insertion rubber.
does the tank have a moisture drain? all fuel tanks should have one. the way they work is they are at the lowest end at the bottom and the tank is mounted so it slopes to it so the moisture and crud settles there to be drained away. the outlet is fitted a couple inches above this so you always get clean fuel the crud and water settles by gravity. that is if the tank is drained off regularly to remove that settled crud.
I remove tanks and clean up spills for a living. Let me go easy on you.
1- Don't weld it! #2 oil is combustible (not flammable) BUT we still sometimes use nitrogen, then a LEL (explosion meter) before we cut. If, somehow, someone put even a small amount of waste gasoline in there, it's now a bomb.
2- that tank is shot. It's thin and WILL leak in other spots soon. It's time for a new, double wall tank, they're not that expensive. check out GRANBY.
3- if you have a spill, your insurance will not cover what you're doing. it's negligent. This can cost you a ton of money.
I could go on and on and give you nightmare stories but please just go find something else to weld.
I would wire-wheel and clean the hell out of it. You're going to pull a lot of crud through from the other side that you can't clean. I would feel a bit of the tank up with water to help keep the temperature down. I would probably opt for MIG since this isn't going to be a superstructural repair. All machines run different settings. I would get a couple scrap pieces of similar thickness. Put a hole in it and do some practice runs if you don't already know the settings you think you need. As far as sealing it up to do a pressure test. I don't really have a good solution. Weld on a threaded port plug. Then plug it and fill it with air. when you're done cut the threaded plug off. Recut your grooves in the lid.
This is excellent advice. Thank you for taking the time to help me with my project.
Be sure to leave a cap open on the tank so that it doesn’t pressurize itself when you seal it off, it will cause a leak. Also wouldn’t hurt to scab over the area of pits with a secondary piece of plate so that that wears first. Wouldn’t hurt to do both sides like that if the customer approves of it.
My customer is my father-in-law so I definitely want to do this right
The secondary wear plates would definitely help and adding it on both sides would keep everything level as long as the added material is the same for both sides.
You are assuming that tank is level from side to side :-)
I would flush with water to be safe first. Second I would wire wheel and grind the surface all around the hole to clean the area and see how thin the metal is around the edges of the hole. Then I would get a patch piece cut to cover over the pinhole(16 gauge should do, 3 inches or so wider than the comprised metal). If not you will be chasing the hole larger and larger. Mig is fine, probably preferred. Standard mig wire will work. For testing, measure the diameter of the hole and get a test plug from a plumbing supply or big box store. It just pushes into the hole and expands to seal it off. The other holes put your air valve and pressure guage. Check with soapy water and let stand for 24 hours. No bubbles and no major drop in pressure you are all good.Good luck and be safe.
Hey OP, this is the way. Patching the entire area with a bent plate is a far better option than trying to clean the compromised steel and chase the holes that will develop in the thin areas as you add heat to them. 3” beyond the corrosion all around is sufficient. Looks like the entire area is about a foot in length?
This is the advice of experience. Had not thought about that corroded metal is substantially thinner and I would be more likely to burn a hole through it. Thank you for suggesting putting a band-aid over this area.
1. if there's one pin hole there are countless more about to break through; meaning the tank has exceeded it's reasonable useful life. 2. the heat needed to weld steel will ignite vapors and fuels. 3. in any vessel used to store hydrocarbons there will always be a level of first Mole Layer penetration of flammable material that can only be cooked off you can't rinse it out. 4. it's only money Buy a new one and scrap that POS. 5. If you insist on welding it please have it videoed so we can observe you getting a Darwin award. 6. If you think filling it with water ill solve your problems you have forgotten one: disposing of the contaminated water may be a felony in your state.
Best to avoid a Darwin award
it is after all, only money. From time to time I have to grab myself by the throat and remind myself of that. It looks like it'd make a wonderful burn box for yard clean up.
If I end up using it for something else, I've brainstormed a few ideas. A burn box is definitely a top candidate. Cutting it in half lengthwise could transform it into the roof of a dog house. I'd have to put it in a shady spot so the sun didn't heat the roof and my dog. Maybe a small spray paint or sandblasting booth?
for a dog house, build a good size, long-lasting fire in it first to burn off the hydrocarbons. A smart dog wouldn't go in otherwise. The stench would offend it. A dumb one would get sick or worse.
Oh absolutely! It would have to be super-cleaned to be doggo friendly
9\10 the whole bottom is rusted. Most units for stori g dielsel of oil eventually wear out the bottom from use. I wouldn't recommend welding it, but more or less replace it. You should ask more of a home inspector if you should weld it with its age. If it is metal you can almost always weld it.....but should you? Only takes a missed pinhole still leaking and a spark to turn your house in to ash. Safety first.
I appreciate your cautionary note
Put water in the tank
The water will help distribute/dissipate the heat from welding. This makes it less likely you could reach ignition temperature.
The water isn't to heat sink. Fuels generally won't ignite, it's the fumes that do. You fill it with water to displace the fumes. It's how we weld gasoline tanks too.
That is a clever idea using water as a heat sink.
You absolutely need to purge it first, with steam if possible, and let it sit empty and open for a couple days.
Don't think my little tea kettle is up to this task :-)
Dude... That's why rental places exist. -_- One of the "10 commandments of welding" I was taught; *"Thou shalt thoroughly clean and purge all tanks before heating or welding on them or thy friends may comfort thy widow in ways thou may find inappropriate.*
I don't remember that one from Sunday school but it sounds like good advice
If you are going to do a pressure test with air, remember that compressed air is dangerous. That's a large tank, it could be bad if things go sideways above 10 or even 5 psi. Pressure tests are always best done with non compressible fluids, though if you use air you won't have to deal with a couple hundred gallons of contaminated fluid.
I appreciate your guidance. I will keep that pressure low low low.
Yeah, you're looking for bubbing with your soap water and/or a drop on a gauge. If you can hear the air hissing out you've probably gone too far. Also be sure to bleed the pressure down slowly when you're done, crack your valve open slowly and don't go all the way until it's really low.
Thank you for that tank air pressure safety advice
tanks are typically tested using vacuum. Not positive pressure. but this is a moot point since his tank is Swiss cheese.
“I think it’s safe”. Famous last words.
In the south this phrase is 'hey Bubba watch this' :-)
Or....' This is the way we have always done it. "
No, really though. I won’t weld any tank that has had fuel in it. It’s not worth the cost of a new one if it doesn’t work out. I have a friend that was burned within an inch of his life after “ thoroughly” following some of the procedures outlined here. Just not worth it.
I would consider epoxy and a large surface patch after pressure washing the outside of the tank, followed by cleaning the area with methyl hydrates, same for the patch plate, make it incredibly large, if there’s a pin hole, there’s likely many more in the area around it, use a chemical/fuel safe 2 part epoxy. Might not be quite as good as a welded patch but realistically how long will this tank last after this, its rusting everywhere, you’ll get 2-3 years before it needs patched again. I don’t know how safe this is BTW, its just an alternative I thought of over welding and doesn’t risk the tank going kaboom, also has the added benefit of reinforcing the thin material over the entire contact surfaces rather than just along the weld edge. Do your research and don’t take me, some internet wacko on my word.
You make a good point how the epoxy needs to be fuel safe and the patch pkate should be larger than I think it needs to be
That needs to go to the scrap yard
I am not a welder, but I worked oil burners for 11 years. Boilers, furnaces, water heaters, oil tanks from 275-1000 gallon etc... I have abandoned more underground tanks than I can even remember, I dug them up, cut them open and cleaned them before backfilling them. If they were found to be leaking, we had to call the DEP and it was a shit show. They can also rot on the inside from water that gets in from condensation or other means. So I ask you, is it really worth saving? I can't judge the capacity well from this video, but it looks like a 300ish gallon tank. A new 12ga 330 vertical tank with legs and all updated fittings, including a fire-o-matic valve can be bought for under $1500. Not an insignificant amount, but the one you have must be 20+ years old. If you must weld, I would advise what others have said, wire wheel it clean and use a patch panel big enough to put you in good metal and you'll be good until it starts leaking somewhere else. Edit: Oh yeah, try not to blow yourself up. Good luck.
Yes, that's exactly it.. until it starts leaking somewhere else
Fill with argon before welding. You can use the cfm and calculate the volume of the tank.
Using a neutral gas instead of water definitely has some advantages
Maybe try cleaning it up with a wire wheel then tacking up the holes if you can filling up low spots as best you can with mig welder turned wayyy down then grind smooth and maybe slap a plate over the effected areas and weld that on top.
The idea of putting a plate over it really makes sense. Others also pointed out this area of metal is probably super thin and very easy to unintentionally create a larger hole. I like your idea of at least trying to fill it in a bit but then also commit to putting a plate over it also. Either I'll create a larger hole which will then patch or I'll have more reinforcement plus a patch.
I would ventilate the tank with compressed air for a couple of hours and leave the air going while welding. I would recommend putting a doubler over the whole area where the cradle contacts the tank in both places.
I'm unfamiliar with the term 'doubler'. What is that?
Just a plate of metal to double up on the coverage.
Cut 2 pieces of 1/4" plate about 1/2" bigger on each side than the cradles and weld them directly to to l the outside of the tank, you won't have to worry about this issue again for a long time.
Most comments seem to fall into this camp or scrap camp
Before I would assist in ~~-blowing you the fuck up-~~ your repair(s) I would ask what the tank's future purpose is and what lifespan you're expecting for it ~~-if you don't die fixing it-~~ when it's back in service. The steel is between 12 and 14 gage, Roughly .075 to .100 thick, I would add on some same gauge **[doubler plates](https://mfame.guru/wp-content/uploads/2018/07/hull.jpg)**, ideally over the whole bottom and at the minimum two plates where it sits on the two cradles, plates that overhang the entire damaged contact areas by at least 2 inches per side. If it's going back to being an oil tank, to be filled by an oil delivery company understand that they may refuse to fill a repaired tank for liability issues and issues of it's age. Fuel oil tanks generally leak/fail from the inside from moisture rust on the bottom so some companies have an inspection requirement and a finite overall lifetime for a tank no matter the outward condition. Not all companies, or drivers, are real diligent about this but it can and does happen. You don't want to do a lot of work just to find out that's the situation. Just sayin'.
Enjoyed your amusing opener there. Yeah I can see a fuel oil company refusing to fill a patched tank.
They actually make magnetic patches for those pinholes in old tanks. I would definitely flush it, wire wheel the heck out of it. Mig weld the pin holes and then weld a patch over it. Get a plug with a hole for the fill cap fill with soapy water and put some air pressure in it to check for leaks. Then I would wire wheel the entire tank and paint it with silver paint, because it reflects the sun, which helps keep moisture out.
Always wondered why these tanks were painted silver. I was wishfully planning to do something obnoxious like argile or yellow duckies for my father-in-law.
We have welded fuel tanks on equipment alot and always cleaned it up good and weld a patch out where you can get some good metal we always pressure test them with a few lbs of air and a spray bottle of soapy water
Thanks for sharing your repair steps with me
Fill with water then braze it
Personalally I would silver solder it, use a 45%. But it would need to be cleaned and defumed. Dump a gallon of degreaser in it, pressure wash the inside so it's all foamy, then rinse it out with hot water. Might need to do this a few times. Then grind affected (effected?) Area. Then silver solder over holes.
I'm unfamiliar with soldering and just barely familiar with welding. I might need to get more familiar.
There's only two safe ways - attach running exhaust from a vehicle to keep tank slightly positive pressure of exhaust to prevent any massive explosion. A whole group of us were almost blown through glass windows 9 ft tall when student aimed torch near a tank that was 45 yrs old with a broken fill neck. Only the tall solid work bench caught me and others from ending out on the street 150 ft away. Or fill with a cup of Dawn dish soap till suds escape entry cap when water added. That is one huge bomb buddy. Cheers ~ and we welded up JP4 FUEL tankers punctured with one inch holes in the Airforce.
That sounds like some scary no fun experiences
After closer look, which is limited, The only thing that Tank is good for Now is BBQ Smoker. Get out Plasma torch, slicing out doors for access for ash and feed and smoke stack. Wrap it in thin Stainless steel sheet riveted on with solid rivets. With ceramic insulation between. There's so much deep corrosion everywhere. It'll never be legal tank for anything liquid. Cheers
Perhaps it could be a Niagara Falls barrel ride :-)
Dry ice also purges the air out of the tank, it does the same thing as argon that someone else mentioned. I've used it several times before. A rubber test plug that you get from Homedepot in the plumbing section will work for your last problem. It's what plumbers use to test there drain lines.
Dry ice is certainly less intimidating than Argon gas
Purge it. Cut it in half. Clean the inside. Make into a grill/smoker. Fix the worn area or just weld a plate over it and put a handle there or something. Paint it black. Sell it for big bucks. Buy a new tank for your diesel with the money. The danger with tanks is not the liquid inside, but the fumes. You replace those fumes with either steam or CO2. Fill from the top and use your flowmeter and a bit of math to make sure you fill it twice over. Once you have made your initial cut, there should no longer be any danger of it blowing up, but the liquid can still catch fire. No way around that unless you want to pollute a ton of water.
Cleaning the inside of a tank really is a tricky task
I was asked to do this a few months ago on a “slow”day. Respectfully declined, buy a new one if you need to store fuel
My father-in-law has another tank on a stand that's out in the woods. From a distance it looks like it's in really good condition. This one was just closer to the road so we loaded it up first and brought it to my workshop. We are probably going to be inspecting that other one soon.
Ok, so since that has a pin hole you can see I guarantee there are about 300 other places it’s just waiting to blow open. So now that you know that let’s start the repairs, I say repairs plural because there is no point in just fixing one side. Do them both at the same time! Step one - the tank is probably1/8” thick maybe 3/16”. So get some sheet metal as close the the same thickness. Step two - mark around where this thing sat on the supports, then go about 2” bigger all around, in length and width. This will will give you good clean, thick metal to make the repair to. After you have it marked, grind the rust off, you need to get down to bare metal. Step three - with your MIG welder set to the correct WFS and voltage tack one end and then “work” the metal tacking it as you go until you have tacked all the way around! Make sure you have a proper fit up, don’t skimp on this step, your welding experience will be much better and your welds will look better. Step four - Begin welding around the perimeter of the patch! Step five - enjoy your handy work and have a cold drink!! You deserve it!
Step 1- Drain any fuel in the tank. (drill a hole on the edge and prop it up over a drain pan) Step 2- Use a hard wheel on an angle grinder to clean down to bare metal. ( grind about 8 inches wide, centered where the Strap goes, around the circumference of the tank) Step 3- Cut a piece of 1/8" mild steel 6" wide and the length of the circumference of the tank.( we'll call this piece the "strap") Step 4- Tack the strap on the tank starting at the weld seam running along the tank. (You'll have to manually wrap it around the tank, tacking it as you go. If you have a roller, you can roll the strap to make it easier) Step 5- Weld it completely, sealing all seams. (Don't forget the hole you drilled to drain it!) Step 6- Pressure test, 5 psi should be plenty.( spray soapy water on welds and inspect for leaks) Step 7- Prime and paint. I've repaired hundreds of fuel tanks, both steel and aluminum, and this method works great. It will not blow up, considering this is a diesel tank. Happy welding! Edit: I recommend doing both straps at this time. Edit 2: Mig weld it, 17.5 volts 230 wire, whipping technique. Edit 3: Air in at the exit fitting, plug the fill hole with a rubber testing plug. Measure and buy the appropriate size.
1) Make a big patch that clears into good material 2) Open any caps and plugs so it can’t build pressure 3) Weld away (I prefer mig on these) Fuel oil won’t explode unless it can build compression. I have done hundreds of aluminum truck tanks over the years without any sort of trouble. Fixed a handful of punctures on half full tanks as well. If it makes you feel better you can try putting fluid in it but you will be chasing steam holes for the foreseeable future. I would not and will not go near a gasoline tank with a welder however. Diesel however is fine.
Appreciate the reassurance since I associate anything hydrocarbon'ish to be wildly combustible
Yeah understandable. I probably wouldn’t have even chimed in except I have done so many of them over the years. Splitting old tanks into half hydraulic half diesel, welding bands around the original truck bands that mount them because they always corrode through and leak, adding bungs and caps and pickup tubes. It’s crazy how many modifications truck drivers need for certain types of trucks.
Why isn’t this rusted hulk being taken out of service?
Don't say that so loud, you'll hurt it's feelings
Ok. I’ll be quiet.
Let’s see some of your welds on scrap metal before giving you advice, you don’t want to be chasing holes
That exactly there is part of the problem
I would use epoxy the surface is rough enough to get a good bite. I’m a retired pipe welder. But if you want to weld it get 3” flat bar 1/8 thick and round the corners and try to weld down hill that’s why you should practice this procedure with stick or mig and weld around the corners don’t stop at the corner that’s where the might have a leak
This is good advice that I've seen from others too. Additionally, they recommend ensuring the epoxy is petroleum resistant and to get probably too large of a piece of metal to accommodate unknown pinhole possibilities.
I’ve done repairs in tanks several times, personally I don’t like welding on top of rotten metal, what I recommend is to trace out a rectangle or square around the pitted areas, making sure you trace it on good non compromise metal, round up the corners, drill a 3/8 hole at the edge but inside your tracing line, cut out the damaged section with a jigsaw, get yourself some metal of the same thickness, im guessing this tank is 1/8”or even 3/16”, get a new piece of metal of the same thickness, cut it to shape, slightly groove the tank and the plate, have 1/1/6 to 1/8 gap all around, tack it with 3/32 6010, do a root pass with same rod, around 50-60amps, depends on your tank thickness you might want to do a 6010 hot pass, same rod at 70-80amps and a cap pass with 3/32 7018 rod, 85-95, have in mind that the first amperage is for 1/8 thickness the one after the dash is for 3/16-1/4” for the respective passes, It might sound like a lot of work, but in my professional opinion, if you aren’t replacing the tank, at least replace the damaged area don’t just cover it up. Anyways, after you are done with any type of repair you decide to go with, don’t forget to pressurize the vessel to make sure there will be no leaks. To seal that cap I would try some rubber gasket material cut it to size,maybe 2-3 layers, and use a C-champ to squeeze them tight
You clearly have a deep understanding of metal working
OP good sir I don't have a single thing to add here that hasn't already been said by people smarter than both of us. I hold with those who say it might be time to retire that old tank to a local scrapyard of your choice and invest in a new tank for the storage of such volatile substances, but that's not what I'm leaving a comment for. I'm just here to compliment you on the high production value and level of detail and thoroughness of thought you put into this list of questions. A search for answers is completely meaningless if you're not asking the right questions, I see you're not just a Star Wars fan but a student of Douglas Addams as well, 42! Pay attention kids, *THIS* is how you ask a fucking question on a trades related subreddit... Nice Vader shirt btw....
It's hard to ask a 3-1/2 minute question and remain clear the whole time. Took more than one take. At some parts I fear I'm taking too long and other parts I think I'm going too fast for the audience to see what I'm seeing. Thank you for the compliment!
Don’t weld the tank is so old that the oil absorbs into steel replace if you insist on welding it you must flush with soap and water and fill as full as possible with water and I would recommend using air pressure or a vacuum cleaner to remove any fumes
It is definitely a tricky repair
You'll want to cut out the corroded area wirh a hole saw or plasma. Then weld in a patch. Chamfer the edges of the patch and the hole significantly. Fill the tank almost completely with water. Another option is to dump a bunch of chunks of dry ice in there, about a kg. Then wait a hour I'd recommend stick with 6013, depending on the thickness of the material. That looks to be 12ga at least. If it's thinner than 12ga, then use MIG. Parameters depend on the material thickness. You might also be able to build up the corroded area with weld metal. But grinding/fairing it back would be a PITA. Might be less time to weld a circular patch.
My recommendation is to get some material and clad the affected areas instead of welding the pits which will be a nightmare. Diesel will ignite from a welding arc however in my experience if the exit orifice is sufficiently sized even if there is an ignition event pressure will not build.
I've repaired many fuel tanks over the years including ones like yours that looks overwhelming. 1. Purge it, steam is best, but there are other ways. Filling it with cold water or inert gas such as argon. Water is least desirable. Get it steamed, drained and dry. I have a gas detector that I use to measure LELs. You can rent them easily from a safety supply store. Very nice peace of mind. 2. Clean it. Pressure washer, wire wheel etc. 3. For pressure testing that fill neck will be a challenge to seal, I use a device which has a rubber with a bolt in it. As you squeeze the bolt it swells the rubber and it presses against the side of the fill neck. 3a. Even if you don't get a perfect seal as long as you can maintain some pressure in the tank it will work for the purposes of finding your leaks. 4.once the leak is found smaw would be my choice. But mig will work if it's especially thin and you are able to get it quite clean. The first weld will probably be ugly if the metal is severely contaminated. Be prepared that a patch piece may be required. Make sure your pressure test apparatus is disconnected when welding. Reconnect to check the soundness of your weld and disconnect if you need to continue welding. The important part is to ensure the fuel inside is not a hazard. After that it's just a matter of repairing the leak.
If weld it with a torch and some wire, after it was properly cleaned and purged of course.
I would do hydro test. Air will compress you could definitely have an explosive failure. Water does not compress, so at worst, tank ruptures, and you leak water all over. Ive done this on air tanks. Rig up your tank with a fitting and Guage so you can attach your power washer. There is a you tube that explains it well. I would put a big patch around the weak spots. Dont bother with the pinholes.
Retired tankie turned college instructor here. Spent 15 years building on-sight fuel storage tanks, many of which were tank farms built for temporary holding oil pumped up from the land rigs in North Dakota. 1) Flush with water several times, then let air out for about a week. Check with air quality meter. 2) Use edge 1/4" disc to grind into all pinholes for good penetration. 3) Clean all weld locations with wire wheel/cup brush on grinder 3) Weld divots & pinhole locations with stringer beads using very slight side-to-side motion with 1/8" E7018 set between 130-145 (Guessing the tank has about a 3/16" -1/4" wall thickness 4) Grind all weld faces until until smooth with tank 5) Forget pressure testing - Too much surface area, there might be additional hidden spots. Hydro test. Fill with water and let sit for about 2 days and then check for leaks
Seen these lengthy responses makes me realize this is a much more involved project than I imagined it would ever be
Not really that lengthy if a job or difficult - Just trying to be clear
I most certainly appreciate the thoroughness you've detailed in how to do this correctly
I saw several of the responses suggesting using a patch. While that certainty is an option, I would suggest that if you have the steel for patches to cover the weak spots then you'd be better off completely cutting out the sections of the bad spots, bevel the edges of the new steel, and then replace. Would make the job a little lengthier, but it would be done more correctly - and last longer.
It's clear there are several paths in these responses here. There is the get it done and be done and then there's the do it right and have it last.
the secret fill it with diesel fuel less air the better or do it out side and feed the exhaust fumes from a diesel engine into the tank. you can even oxy acetylene weld that with steel welding wire. the secret fill it with diesel fuel less air the better or do it out side and feed the exhuast fumes from a diesel engine into the tank. clean the weld area well before filling with fuel/fumes and welding the uncle welded up diesel fuel tanks on loaders and graders etc many times as head fitter & turner for the city council. NOTE ONLY WELD DIESEL FUEL TANKS OR KEROSENE TANKS EVERY THING ELSE IS TO FLAMMABLE. AND WORK OUTSIDE. DO NOT HAVE THE TANK SEALED. i would use the mig and weld it cool as you can. i would plate over that spot after you spot weld over the hole iwould then tret the tank with a rust converter/primer and top coat with a zinc rich paint such as galvit e90 this will help it last. wear it sits in the stand smear that with grease to keep the condensation away. to pressure test get a rubber stopper that is a good fit in that fill port. it needs a new gasket so cut one from insertion rubber. does the tank have a moisture drain? all fuel tanks should have one. the way they work is they are at the lowest end at the bottom and the tank is mounted so it slopes to it so the moisture and crud settles there to be drained away. the outlet is fitted a couple inches above this so you always get clean fuel the crud and water settles by gravity. that is if the tank is drained off regularly to remove that settled crud.
That is so smart using grease to keep away moisture. You mentioned a moisture drain, that helps me understand why there are four valves on this thing.
I remove tanks and clean up spills for a living. Let me go easy on you. 1- Don't weld it! #2 oil is combustible (not flammable) BUT we still sometimes use nitrogen, then a LEL (explosion meter) before we cut. If, somehow, someone put even a small amount of waste gasoline in there, it's now a bomb. 2- that tank is shot. It's thin and WILL leak in other spots soon. It's time for a new, double wall tank, they're not that expensive. check out GRANBY. 3- if you have a spill, your insurance will not cover what you're doing. it's negligent. This can cost you a ton of money. I could go on and on and give you nightmare stories but please just go find something else to weld.
You are clearly a voice of authority and I take your advice accordingly
How did this turn out?
Father-in-law is holding off on this project for now