Naw, it wont blow up!

Jerry "You sure it wont blow up?"
Kenny, "Naw. I soldered up a lot of diesel tanks in my day and never had a problem."
Jerry " Well I'm a little skeert"
Kenny " "Naw, it's ok"
Jerry " How come you're standing so far away?"
Kenny "Well, I didn't want to be in your way. Wink, wink."
Jerry "I could fill the tank almost full of water and solder it that way"
Kenny "Naw it wont blow up."
Jerry "Well ok, here goes."

So I had the oxy/acetylene squeezed down real low so I wouldn't have too hot of a flame. Had to melt the old solder off so we could clean it up and resolder the brass bung to the tank. Old solder had cracked and was leaking.
I got the area hot and just had the solder to melt and was sliding the bung off the tank when KaWhooosh!!
Blue smoke blew out of the fill neck and the hole for the fuel guage and left a big plume in the shop.

Ken's wife Carol (who was down at the shop painting some picture frames) "AAAUUUUGGGHH"
Kenny "Chuckle, chuckle, snicker, snicker."
Jerry " What the...! I thought you said it wouldn't blow up!"
Kenny "Chuckle chuckle snicker, snicker"
Carol "Aaaauuuggghh!"
Jerry "You said it wouldn't blow up."
Kenny "It didn't blow up. snicker, snicker. Sometimes they will go wooof a little but that doesn't hurt anything. chuckle chuckle"

So I cleaned up the old solder area and put some flux on it and was going to solder the bung back on.
Jerry "You sure it wont blow up?"
Kenny "Naw. They never blow up. Sometimes they'll whooof a little but they never blow up. Gas tank will blow up but not a diesel."
Jerry "Well ok. Here goes."
Carol "AAuuughh."
Kenny "Chuckle, chuckle, snicker, snicker..."

So I soldered it back on and pressure tested it and no leaks.
I guess Kenny is right.
Sometimes they woof a little but they never blow up.
"Aaauuuggghh"

Kenny "It didn't blow up. snicker, snicker. Sometimes they will go wooof a little but that doesn't hurt anything. chuckle chuckle.

I can just about hear Kenny.
Glad it was you soldering it, not me.

If I've said this once.... I've said it a hundred times... the LEL (Lower Explosive Limit) of diesel fumes and gasoline fumes are nearly identical. Gasoline has a wider explosive range IIRC... but both are dangerous.
You will not ever catch me welding on a diesel tank or gas tank without full flow air ventilation or a good filling of CO2.

Rod

Ya I have seen that and it does get your attention.
I have soldered many tanks - gas and diesel.
I never put a flame to the tank. I use an old prybar as a soldering iron. Works for me.

I had to make the same repair on a blue tank last spring. Along with a few ounces of residual fuel in the tank there was some organic crap that caught fire while I was soldering. It went out after awhile. Didn't hear any wooof though.

I second your post. Just because you have done something a hundred times with flammable substances doesn't mean an accident ain't waiting to bite your arss. I lit a fire to a burn pit full of debris, done it a hundred times, before I knew it....BOOM! SOB flared up and before I knew it I was back first in it. Luckily, only 2nd and 3rd degree burns on my right arm from the fingers to the arm pit. Hurts like nothing you have ever experienced!!

About this time last year I had to relocated the pick up tube and relocate a new fuel sender on a tank out of a 39 chevy street rod,,, best I could figger out was the tank came out of a AMC javelin,,, it did fit up nice but a hack job was done connecting the fuel line to it and the sender did not match the gauge...

I washed it out a few times,,, then stood it up around the corner of the building and while around the other corner stuck a torch in the fuel sender hole... "AAAUUUUGGGHH" big time,,, I repeated till no "AAAUUUUGGGHH",,, then solider in all the new parts no problem... I stood it up on end to get all the water to run to one corner,,, next day go to suck it out,,, I get almost a qt of raw fuel out of it :shock",,, it had a plastic tank inside the tank that has something to do with the vent and I did not see it...

Jerry,

I'll bring you the tank from my 8000 when we get to fixing it. I'm not putting a torch on the darn thing. I got 8 grandkids, and that means about 10 years of tractor building, so I don't want any missing body parts from some big WOOOOSHHHH! I'll even buy both you and Kenny a few beers to celebrate another successful tank soldering job.

Just Kidding, but maybe not?

Paul in MN

Hi Paul.
Ken has been around and repaired more big equipment in his life than I will ever see.
I trust him implicitly.
Six years ago I soldered the gas tank on my 3000 but only after washing it out with lacquer thinner, then soap and water and then letting it air out for a few days.
Sure I could solder your tank. Sometimes the bottoms are like swiss cheese from rust and then not worth it. But a pinhole or two or a crack or a leaking bung is not difficult or particularly dangerous.
Let me know.

It's that first wave of the torch over the hole that really makes the ol sphincter tighten. Once you get past that you're ok. Your job would have given me nightmares afterwards.

To each his own, but I personally won't apply flame to a fuel or oil tank unless I'm purging it with a flow of CO2 at the time. I witnessed my dad being blown 10-15 feet across the yard with the round end of a tractor tank (MM I think) wrapped around his face. He previously rinsed with water, dumped & re-filled with water, being careful to not leave air space, [u:6294c5d2a7]and had already had flame applied for a minute or more when it blew up[/u:6294c5d2a7]. He always surmised that there was fuel remaining in the seams that the heat liberated that resulted in the explosion. He didn't stop doing it, but he always ran purging gas during welds after that & never had another blow.

LEL of gas is -45 deg. and diesel is 145 deg. so how are they close ??

(quoted from post at 21:28:04 04/09/11) LEL of gas is -45 deg. and diesel is 145 deg. so how are they close ??

Click to expand...

ower Explosive Limit is expressed as a %..........so what is your degrees?
OK, your degrees numbers are flash point, i.e., the temperature where an explosive vapor can form. Well, torch temperatures FAR exceed either one by one or two orders of magnitude, so your point is???

I have two stories: Wife's uncle's friend welding hotrod gas tank. Dead! Local kid welding muscle car gas tank. Little bitty ears, nose, lips, eyelids, eyebrows; stubby fingers, all visible skin appears melted. Very lucky to be running repair shop 10 years later. Wonderful attitude.

You never heard of an electric soldering iron or and old soldering copper you can heat with a torch I guess.

As a PPM figure they are statistically identical. PPM is what counts, not temperature. I'd have to go and look up the numbers because it's a while since I looked... but I know it's close enough that ~I~ will not chance it. For anyone that knows me.... that's saying something.

Rod

A couple of thoughts here.
Ever use gas to set a brush pile on fire? Pour some gas on the pile and then pour a "fuse" on the ground and light it? All you have to do is throw a match to the fuse and KA-WHOOM the whole bunch of gas is burning instantly. To light a brush pile using diesel you have to take a torch made out of rolled newspaper and apply the flame directly to the pile.
Or, we all know what happens if you throw a lit match into a small pan of gas. You can not get a similar pan of diesel to light in a similar way.
I don't know the technicalities of LELs and all that but I do know that gas will blow up much easier than diesel will.

2Fordsmike, you are giving examples of GAS tanks blowing up. I agree with you about using extreme caution when soldering GAS tanks. This was a DIESEL tank - see above.

36 Coupe, you would be hard pressed to get enough heat from a soldering copper or electric soldering torch to get one of these bungs off. I do have an old soldering copper and they work great for soldering pin holes in a thin sheet metal fuel tank but could not apply enough heat to effectively solder this bung.
I could have stuck the mig welder into this tank and filled it with CO2. I would have if it had been a GAS tank. Plus would have used other safety measures as well.

Jerry... the thing you need to remember with LEL is that we're talking about vapors. The vapor will explode just as easily.
This is NOT to say that diesel will vaporize as easily tho. With gasoline a small amount of liquid fuel will quickly form a large amount of vapor that is explosive. The same amount of diesel may require a lot more time/heat to form that same volume of vapor to enter the explosive range.
The trick is.... who really wants to guess at when that amount of diesel will reach the explosive range? With gasoline you generally assume it. With diesel... most people don't... but if you're dealing with a contained atmosphere such as a tank... the potential is always there.

Venting either tank remains as simple as running a large flow of air through the tank. Applying air does two things. It disturbs layering in the tanks so that the vapors are fully mixed and the absolute volume of air going in will supply an air change. As always, the solution to polution is dilution. If you lean the mixture out, it's not going to blow.
This is probably not something that most people know.... but anyone who has done any amount of fire training, particularly with regards to gas monitors and ventilation.... should know this.

Rod

(quoted from post at 09:10:31 04/10/11) Jerry... the thing you need to remember with LEL is that we're talking about vapors. The vapor will explode just as easily.
This is NOT to say that diesel will vaporize as easily tho. With gasoline a small amount of liquid fuel will quickly form a large amount of vapor that is explosive. The same amount of diesel may require a lot more time/heat to form that same volume of vapor to enter the explosive range.
The trick is.... who really wants to guess at when that amount of diesel will reach the explosive range? With gasoline you generally assume it. With diesel... most people don't... but if you're dealing with a contained atmosphere such as a tank... the potential is always there.

Venting either tank remains as simple as running a large flow of air through the tank. Applying air does two things. It disturbs layering in the tanks so that the vapors are fully mixed and the absolute volume of air going in will supply an air change. As always, the solution to polution is dilution. If you lean the mixture out, it's not going to blow.
This is probably not something that most people know.... but anyone who has done any amount of fire training, particularly with regards to gas monitors and ventilation.... should know this.

Rod

Click to expand...

good example, I think, of the explosive vapor you speak of would be the white cloud that is created in an open burn barrel when diesel is poured over the smoldering (not flaming) hot coals in the bottom of barrel. Then throw a match into that white vapor cloud!


The narrow range of the short bars is why we have survived around these fuels as long as we have.
It is also why things have to be just so-so for your engine to run.

Empty completely, clean, purge and then purge again and you are usually OK. I do not use water.
I like to use my large soldering iron when it will transfer enough heat.
The torch is the last resort.
Brian
PS I worked with guy who was helping his friend build a dock with sealed 45 Gal. drums. He was burnt badly when a drum blew up. His friend, who was using the welder, had his head removed with the lid. Be careful!

I've soldered, brazed or welded several gas tanks. It can be done safely!

The procedures I use haven't been mentioned here. I was going to post step by step instructions but decided against it because if you don't follow the procedures EXACTLY you can turn a safe job into a deadly one!

If you're getting a whoosh, aauugghh, or any other sudden sound, you're not using safe procedures!