Welding Fuel Tank

[Ronsii]

The one problem often overlooked on using engine exhaust-make sure the engine is running slightly on the lean side, your not making headway running a rich exhaust.

Yep, anybody that has seen what a rich running motor does to it's exhaust when it 'backfires' knows what you mean!!!

 

[Queenslander]

We bought this ex rail car tanker to store molasses in some years ago.
Even though Qld Rail decommissioned and degassed it, as well as torching off their outlet gear, I was more than a little apprehensive about blowing a hole in the 3/4 thick end wall for our outlet.
After hearing all the horror stories about exploding tanks, I believe I shut my eyes and said a quick prayer as I squeezed the lever of the torch.

 

[grandpa]

There's a guy running around my area with a face so scared and no ears, so I don't touch fuel tanks. Period.

 

[Truck Shop]

If you don't have a LEL meter to measure the combustible gas/oxygen level and a confined space card in your wallet with schooling on working in confined spaces, my best advise-
Don't cut or weld on a vessel that had combustible fluids in it, and stay the hell out of the inside if you've had no confined space training. If it doesn't get you from the explosion
or fire and you get inside with out proper gear you have a great chance of dying from lack of clean air. JMHO. Another words Don't F@uck with it if you don't know what your doing.

 

[Nige]

......... Another words Don't F@uck with it if you don't know what your doing.

Amen to that.

 

[Vetech63]

I personally will NOT weld or cut on any type of fuel tanks. I worked for a general contractor back in the early 80's removing old fuel station tanks. They were supposed to be cleaned and cleared before cutting up, which was done, but one of our guys hit the side of it with a quickee saw and as soon as the blade sparked inside the tank, it exploded. The end blew completely off the tank and decapitated the job foreman. I didn't see it happen, just the aftermath.

 

[DMiller]

Tons of these horror stories out there where Luck just ran out, don't be a add on to the list.

 

[Welder Dave]

If you don't have a LEL meter to measure the combustible gas/oxygen level and a confined space card in your wallet with schooling on working in confined spaces, my best advise-
Don't cut or weld on a vessel that had combustible fluids in it, and stay the hell out of the inside if you've had no confined space training. If it doesn't get you from the explosion
or fire and you get inside with out proper gear you have a great chance of dying from lack of clean air. JMHO. Another words Don't F@uck with it if you don't know what your doing.

I went for work experience at an oilfield welding shop in high school. I went with one of the owners in a welding truck to repair a crack in a vessel at a refinery. He used a meter to record the gas level and said if it would have been any higher he wouldn't have went in. It was about 85F outside and I could stay in the vessel about 5 minutes before I had to come out to cool off. He could stay in about 10 minutes but was used to it. The vessel had been steamed for 2 weeks and still barely met safe levels!

A tank shop I once worked at had a bad accident a couple years after I left. They were coating the inside of a large new tank in the paint shop and a static electricity spark ignited the coating, blowing the tank off the supports. No one was killed but 2 painters were badly injured. One of them took over a year to recover.

 

[DMiller]

Used to weld Gas tanks at a old garage by my Folks house. Old man(Less than my Current Age) sat me down with a Briggs and Stratton tank needed a seam brazed, showed me to open every opening on the tank light the fumes and go to welding while flaming!! Bigger tanks as off a car or pickup he would torch weld full of gas or would fill with water, just depended on price of gas that day.
Older story was a small garage in Portage Des Sioux MO had a regular client, asphaltic oil spreader truck, used in chip and seal operations, they had worked on this nuisance many times. Summer day, old dog asleep under another truck, mechanic goes to replace a broken off mudflap bracket ahead of the rear axle, truck had sat inside the garage all night. Short Story longer and more boring guy got geared up, had spot prepped and angle iron clamped up on tank frame, struck a slight arc to know had ground. He woke up in a haze momentarily afterword's, head hurting ears ringing, unable to hear much at all, laying on floor could make out the dog high tailing it across a nearby farm field. Then realized was REALLY bright, like daylight, then really came out of it knowing the roof was gone.

Seems the first arc was enough to set off the gasses inside the Open and vented tank, which was now a flat sheet of steel dripping bitumen with insulation and lagging scattered everywhere, one side wall of the garage was GONE, mechanic was lucky to escape minor injuries remained deaf in one ear after, luck was the tank seam was UP and he was Under when it exploded limiting his injury. Truck was destroyed, garage closed never reopened, mechanic retired. Dog WAS found later and would not ever get near a garage shop ever again.

 

[Truck Shop]

Well that's a smart dog, maybe the owner should have had the dog running the business.

 

[DMiller]

Mechanic told me YEARS Ago he had done this so many times, even had welded o the booms and hatches, never once considered a Bunker hauler as explosive.

 

[Truck Shop]

Well bunker oil/crude is full of propains until it goes through a process for shipping by rail car or truck. The problem with that is the process doesn't always take place. I know that from
a old platform boss for Brinkerhoff Signal Drilling. Crude is a very dangerous substance especially when it's confined in a vessel, even with vapor recovery.

 

[Steve Frazier]

Well there are enough horror stories here to get my attention, I won't be doing the welding without addressing the fumes. The dry ice idea sounds like it would be my best option.. I had to wait for the tank to be near empty so I could both move it to my shop and roll it on its side to address the bottom. Thanks for the other suggestions.

Truck Stop, thanks for the tip on patching. I was wondering if I would be able to get the pits clean enough for the mig and I don't want to risk burn through with a stick.

Now to decide on the color LOL!

 

[Coaldust]

Dry ice, exhaust gas, argon or nitrogen inserting. Burning the fumes, welding with a full tank. It all works 90% of the time. With non-spec Jet A or ULSD tanks, I drain all liquid and vent with air for 12 to 24 hours and sniff with my 4-gas meter until I see 000.0% LEL. Fill out a hot work permit and weld away. I feel safe doing that.

I forgot to mention that I bond the tanks with a cable to a good watch ground as best practice. Then, I fill out a all-clean certificate along with the hot-work permit.

My experience with fuel oil tanks is that with venting, they "dry" up pretty fast. I use confined space style vent fans with trunk hoses. Push the air in, don't draw the vapors through the fan! That's how to make a blow torch.
Intrinsically safe fans are available, but big $$$. I also use air driven Venturi fans that are 100% intrinsically safe when I have a big air source.

Venting ULG or methanol tanks require some extra steps. I try to flush gasoline tankers with ULSD before working on them. Gasoline tends to be latent. I'll vent a gas tanker clean and the next day the LEL will jump back to an unsafe level.

I'm in the tanker biz, so I deal with this all the time.

 

[Welder Dave]

Argon can be used but very expensive! Diesel fuel tanks are probably the easiest to get to safe levels for welding and cutting. Semi diesel fuel tanks are repaired everyday. Gasoline requires much more stringent cleaning requirements.

 

[Nige]

I was going to say that too. I've never seen a problem welding on a diesel tank provided a few basic precautions were taken. TBH back in the day before Hot Work Permits and the like we'd weld minor cracks in welded diesel tank seams by filling the tank right up to the filler neck with diesel, close the cap, strike the arc and weld away to your heart's content.
Gasoline/petrol or heavy oils/aromatics, now that's another story altogether.........

 

[highwayghost]

I've repaired rust leaks on diesel tanks using JB Bond and it lasted years.

 

[Steve Frazier]

As I got further into cleaning the tank for painting I discovered the pitting was much more extensive than I thought, the bottom third of the tank would need replaced. Priced a new tank, around $1200. Went on Facebook marketplace and found a clean 500 gallon tank with pump for $300. Went to look at it this morning and it has about 40 gallons of off road diesel in it! It's in the back of my pickup now, I'll drop it at my shop after lunch.

Thanks to everyone who gave advice. If anyone wants my old tank you're welcome to it, I can load it too.

 

[Nige]

The look on people’s faces when they start sand-blasting something like a tank “just to clean the loose scale off” before painting, all to see it fall into a heap of rust before their eyes, never fails to raise a chuckle.

I feel your pain Steve.

 

[Steve Frazier]

Thanks Nige. I really can't complain, I was given the tank over 20 years ago and always intended to paint it because the paint was peeling in areas. It sat on the ground all that time too on just the skids. Had I attempted this back then the outcome would probably be different and I've gotten all these years use out of it besides. I'm sitting here thinking more about it and I think it's over 30 years ago!