emty it upside down for a day in the sun. Turn it right side up, hook a hose to your gas truck exhaust. Fill the tank continuously with exhaust and weld away. Done it many times no problems. Probably not the right way but it works..

 

Have you tried JB weld? It can seal up a small hole. Make sure surface is clean, bare metal. JB won't stick if it has any contamination on the surface(oil/fuel/dust)

Does the tank come off easily? Remove, fill with water(just to be safe) weld, drain, replace. I would not weld on it with vapours in the tank.

 

I wouldn't bother trying. Especially when its empty. Try patching it with sealant if its a hole.

 

I'd be tempted to fill it full of water most of the way, then do what jdgreen says, but with the cleanest gas engine available...

Water is to displace all gases and vapours, less gas = smaller explosion (have to acknowledge it could happen).

That being said, I'd rather buy a new one than take the risk. If it's too expensive, then see my above statement.

Bruce

 

our local welder will weld on any diesel tank as long as theres diesel in it.

 

How? Why?

Bruce

 

dito how why? I have heard of it being done but not sure how.

I have tried the JB weld but it won't hold, too much contamination. I expect the same result (poor weld) if it had fuel coming through the seam at me, same with water.

I could fill it with CO2 with diesel in it and the co2 is heavier than air so it would not go away in a hurry.

I know of a car in australia that mechanics say it has a fuel pump in it that is unsealed and makes sparks in use but the oxygen levels in the tank are never high eneough to let it ignite. this is with petrol(gasoline) far more flamable than diesel.

 

The Roe Innovations fellow prefers if the tank has diesel in it.
Converted ours to a 1½" I think with diesel in it. Welded and cut.

 

You can weld on a diesel tank that is full but my welder is not overly in favour of the idea. I believe the safest way is to have it steamed out and then weld it.

 

The reason guys have gotten away with welding a tank with fuel in it is because the air in the tank is too rich to burn . A fuel tank is much more dangerous empty or near empty than full . Welding a tank that has been purged with exhaust is never a 100 % sure thing . My advise is call a welding shop that specializes in fabrication and repair of fuel tankers and do it right , you only have one life to enjoy .

 

I will only weld diesel tanks, never gasoline.
I usually do it one of two ways, either full of water or else completely drain the fuel and use a large constant air supply to purge the tank for a few minutes prior and while welding. Method I use depends on size of tank and how much welding is required. Sometimes, particularly on large tanks I will use both. And yes I have welded them full of fuel too, but its not my favorite.

I will and I know welders who will only weld on tanks that they have prepared, someone brings me a tank to weld and they say its been steamed, thats fine, you sit on it while I weld.....

 

dad delivered a brand new IH 4wd back in the 80's and he was driving it to the new owners farm and the guy behind in the truck saw a little line of leakage on the road they looked and it was the tank (poor weld) they went to a machine shop and he just wiped it off with a rag and welded it up and never leaked again

 

When it comes to diesel there isn't a huge fire hazard, some guys will steam the tanks but I think that is to clean all the diesel out of the seam so that it can be welded properly. I have personally welded half full & empty diesel tanks all non steamed. I guess if your really scared you could add water but then you have to get all the water out when you want to reuse it.

 

Cowards live to weld again...lol

 

My local welder told me he would not weld on my diesel fuel tank unless it was full of fuel! I asked him why and his reply "If the tank is full or almost full the air fuel mixture is to rich to ignite, plus the air in the tank may get hot enough to combust but its such a small amount that it will do almost nothing! vs. having an empty tank that has more air and a much better air fuel mixtur, which if welded on long enough (didn't say how long) could possibly explode from the heat it produces! and that would not be a very pretty sight so make sure it is as full as you can get it and its not a problem!" That is his word and he has had a welding buisness for over 15yrs so ill take his word for it!
Oh and I watched him weld my tank from only a few feet away, nothing eer happend and it hasn't leaked since!

 

When I had my 15 yr vacation from the farm before I took it over when I worked in Alaska . I had to get Hazzwhopper training . UST and agst training . You can and might get away with alot of what was suggest in above posts In all my training and first hand exsperionce and knoiwing a few guys that are no longer on this earth because they thought they could get away with it. There was one guy that was welding on a very large I think it was around a 10K WATER tank that stored run off water from a road . A welder was welding on top of the tank (was full of water from run off rain water) 3/4 full or more .. anyway she blew up there was a little bit of gas vapor from probable a little bit leaked on road floated on top of the water just enough vapor .... blew him through the roof and half block away... only way to weld on a tank that using the water method (which is not recomended is to leave the hose in it and leave the water running making sure there is no air in the tank what so ever.

The problem with welding on a tank that is full (which scares me way less than one that is emty is you will heat the gas or diesel up =create more vapor in the tank .Vapor leaving the tank + one spark = boom. My prefered way use to use a sniffer with a very noisy alarm that can be heard over the welder and take a bottle from the wire feed and purge the tank and keep the tank flowing . If you use fumes from the tail pipe (do not use a gas engine no mater what ) you usually can get away with a diesel fumes but not allways I would use a sniffer to just to make sure . I had a co worker that had to spend 4 months in salt lake burn center thought he would save a few seconds.
If you are cutting open a tank it gets a lot more tricky. I have seen guys sniff a tank cheacks out fine starts cutting an older not continuse with alarm din't want to have someone watch the older meter while he cut . Tank heated up % changed allmost blew him up. Even if you don't heat it up you are intoducing a new air intake to the vessel and the % will change.

I know guys that are alot older than me that have gotten away with it there whole life never had a problem . I also know a few guys that are 6' down and a couple of guys that wiswh they were 6' down..... It just isn't worth it.

 

Let's not get carried away here with horror stories, gasoline fumes are a whole lot different than diesel. The original post was a guy asking about welding a small tank not a 10,000gal tanker. Diesel can ignite from welding so obviously u keep a fire extinguisher around for safety, for it to explode it needs a mixture of fuel and air under pressure. Keep the area vented = don't weld the tank with all the caps on, let it breath.

 

I feel compelled to comment on your statement only for the reason of safety.

I'm not going to debate your extensive experience repairing fuel tanks, from your comment earlier about that you think welders only have fuel tanks steam cleaned to get the fuel out of the crack, I'm inclined to believe its quite limited, but then my opinion is based only on your own words.

To anyone else reading this, you need three things to create a fire and possible explosion...AIR...FUEL...AND A SOURCE OF IGNITION. By removing one or more of these or limiting at least one to the smallest minimum possible is the only safe way to repair any kind of fuel tank, it dont matter what size it is.

While it may seem insane to weld on a tank full of fuel, as was pointed out several times earlier, by having the tank full you are limiting the amount of air inside the tank. To attempt to weld on any kind of fuel tank which is empty and no other steps taken is extremely dangerous.

I suspect the fellow who asked the question in the beginning did so because he was unsure of whether or not he wanted to attempt to repair his own tank. To suggest in a public forum like this, blatant disregards for safety to someone who may not know better, is nothing short of irresponsible.

 

albertabuck and montana : Your comments are stated very well which I agree with 100% . It seems some people like taking chances that may cost them their life .

 

Take it off and steam it properly it or replace it, it's not worth the risk. I've seen people weld tanks with fuel in them successfully, I saw a guy stick a torch in a tank with fuel in it and ignite the remaining fuel in it. But I also witnessed a tank explode and kill a guy, the fuel ignited, burst the tank and he burned to death. It's your life, what are you willing to risk?

 

well that created some discussion. thanks to all who have witnessed some bad stuff eneough to make us think.

I am inclined to think that the removal of oxygen is key and the replacement of the fuel with water would be a good thing as diesel will not ignite on fumes unlike gas, rotate damage and lid as close to top as possible without water flowing out crack fill with co2 from mig bottle and weld happily away.

ps tank size is 2000 litres say 400gal approx.

On a less humerouse note if i didn't post for a few months would there be a thread on me in the off topic?

 

Jason if your read my post closer ( I do relise I am a very poor writter so I relise it is hard to do at times not sure why my secertary Jona has been slacking) with the 10 k tanker you refered to was not a 10k fuel tanker but a 10k water tank with probable les than a gallon or two of contaminated gas in it that gave off some vapor. The point I was trying to make even a normall water tank full of water can have the ability to explode and kill so it doesn't matter if it is a 20 gal. car gas tank of a 10k water tank If you value your life you better do a little homework and be safe . You might very well get away with not following proper procedure 99.5% but that .5% where you get killed of have half of your ass skinn grafted to your burned face doesn't appeal to me.. & for the record although very rare it is possible for diesel to give off enough fumes to explode..

 

I wonder if a bottle of sunlight would have helped in that scenario.

Bruce

 

We empty the tank (gas or diesel) and aerate with CO2 until we do not smell the fuel anymore and continue to put the CO2 to it while welding.
We use a Y adapter on our CO2 regulator that we use for our steel mig welding anyhow. On aluminum tanks that we TIG , we use Argon as my welder tells me that the CO2 will affect the integrity of the weld . But Mig weldiing aluminum tanks we use CO2.
So far this has worked good and safely for us.
We used to fill the diesel tank full then weld but we had a couple of minor fires that scared us enough to take the time and empty out the tank and aerate.

 

All good ideas but I don't think you will have much problem diesel is very hard to ignite unless it's under compression. I've tried with a blow torch and it won't burn.

 

All good ideas but I don't think you will have much problem diesel is very hard to ignite unless it's under compression. I've tried with a blow torch and it won't burn.

It is the atomization that makes diesel volitile, get a injector on a pop tesster and hold a lighter to it, shoot a flame 6 to 10' long. Best thing a tech teacher showed us.

Madsnake

 

We just had a fuel tank fixed on our truck, it was in the shop for a safety and they found the leak and fixed it, problem solved. Don't be a hero get it done by a professional and you won't have any problems.

 

What ever you do, DO NOT USE BRAKE CLEANER on anything you are about to weld or get hot.

 

You are right to becareful using Brake Clean when welding. The hazard only exists when the area is wet from the product. As long as you allow the area which it was applied to air dry or use compressed air to speed the evaporation of the cleaner there is no risk at all or the ability to produce phosgene gas. Be watchful of getting sparks and such into piles of floor dry that are saturated with Brake Clean as those can be an unsuspected source of creating phosgene.

Phosgene gas was the reason most Brake Clean is now chlorine free. Its why it don't work as good as it used to, but I agree the safety factor was a good trade off.

 

my two cents

When i was in the air force (cdn) we drained, mopped upped all the fuel, then aerated until no smell before any work on a tank, mind you we never welded we would have to work in them for hours sealing them or changing probes, if your in no rush, empty it, and leave all the caps of for as long as you can until their is no smell. I heard of welders on a road construction crew being fired for not welding a tank because it had diesel fuel in it. (be as safe as you can), a lousy fuel tank is not worth any amount of healing, IMO, LOL!

 

You all are missing the question here. Answer : With a welder of course

Oh, and a grinder before hand to clean it up.