Welding on a vehicle

I need to repair the driver side rocker on my M101 tow vehicle, a '91 Dodge 3/4 Ton, 5.9L, 4x4, HD susp., regular cab, long bed.

I know I need to disconnect the batt before mig welding. Will I explode if I don't drop the gas tank, too? I'm hoping to make this a morning repair, not an all weekend repair.

I'm no expert, but I've never dropped the tank on my vehicle while welding. Granted I've never welded that close to the gas tank. Sounds like a welding blanket could come in handy for some peace of mind.

How about batts of unfaced fiberglass insulation?


eta - As M4L says and I should have mentioned, the gas tank if just aft of the place I'm welding. I wouldn't have bothered asking if I was further away!

Just use common sense ive never dropped the tank or disconected the batts!! And i cut out and replaced half of my blazer i dont use bondo for holes either i weld them closed!!!

I've welded on a bunch of vehicles within fairly close proximity to the fuel tank.

With that being said, every situation is different and I'd never recommend that somebody do it in a public forum.

I always disconect the battery, neg terminal, not because the battery will blow up , but to keep from screwing up the alternator . Never weld on shocks , or inflated tires on rims, they will explode . I stay away from gas tanks while welding,

I've never disconected the battery on a car, whenever I've welded on them. It shur wouldn't hurt though, I guess. As for the gas tank, if there isn't any leaks, and the tank is sound, you will not have any problems.

On a side note...when welding on a vehicle, I keep a five gallon bucket full of water in the shop near by, with a couple of my wifes larger bath towels soaking in it. Sparks on a seat or in the carpet can go up pretty quickly, in a blink of an eye. That way if anything ever did catch, you can quickly throw a wet towel over it, to smother it out. Take it or leave it.

ryan77 said:

Just use common sense ive never dropped the tank or disconected the batts!! And i cut out and replaced half of my blazer i dont use bondo for holes either i weld them closed!!!

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welded a few feet from tank on underside, leave batt hooked up etc
hospital bill wasnt much....(just joking).... just dont weld ON the tank or NEAR a vent,,


,,,,and any good shop should have a fire extinguisher,,,,,,, reminds me of a true story a few years ago(real) I was rewiring and testing the controls on a street sweeper, and a screwdriver fell on the main power bus and a ground wire connector,,,, instant SMOKE and Lights.... I yell " Oh S--T" and jump out of truck, people in shop know I dont ever say that,,, and start running towards the cloud of smoke.....

.... The boss yells "get an extinguisher!!!",,,,the youngest guy in the shop didnt even unhook the strap on the extinguisher he ripped the tank and mount off the concrete wall!!!! but the main 75 amp breaker tripped,,, just lots of plastic smoke and no fire... thank god!

Now we have to fix wire and the fire extinguisher mount!!

DONT WELD ON THE GAS TANK WITH GAS IN IT!!!! DONT SMOKE WHEN WORKING ON GAS TANK! DONT DRINK AND DRIVE! DONT WEAR SUNGLASSES WHEN WELDING USE A MASK? ALWAYS POINT A FIREARM AWAY FROM YOUR BODY!! WAIT 30 MINS AFTER EATING BEFORE SWIMMING!

This reminds me of another idiot sign I see at gas stations,,,, it says "shut off motor before fueling".... its a good idea if the vehicle rolls away..... but I think they are worried about sparks...........retarded, because the motors are running on all the vehicles that come and go while I am feeling her up.....lame like Oregon's gas station attendant law..... ( but its a job employment law.) but they still have fuel cardlock stations for those of you who know what that is...

sf38a1 said:

Never weld on shocks , or inflated tires on rims, they will explode . I stay away from gas tanks while welding,

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Sounds like a good idea!

With diesel fuel you don't have to worry about the tank flashing as much as when you are working on a gas powered vehicle. i usually top off the tank and tighten the cap to reduce fume build up. I locate where the fuel line runs along the frame so I know which side of the vehicle to be extra cautious. Using a grinder is way more dangerous than welding ( if you're doing it right). If you can, use argon/co2 mix gas and soild wire instead of the flux core stuff. The flux core spatters a lot more then solid wire. Locate the ground clamp as close as you can to the weld area. Make sure the clamp is on bare metal and not paint or rust . So many jobs are ruined by bad ground placement. people underestimate that part of the circuit. If you are really paranoid then chck the wind direction and make sure it is blowing any of the gas vapors away from your direction. Remember that gas vapors are heavier then air and will go to the lowest point around. having clutter (creepers, tool boxes, blankets) in your area can trap that vapor close to your welding/grinding sparks. Good luck.. Go BRUINS!!

I have welded many times right near the gas tank and never had a problem. I sure was nervous about it though!!

One thing to keep in mind when welding on a vehicle, as was mentioned, the potential for fire. Don't get too caught up in your welding job that you don't check to make sure there are no fires going every 15 seconds or so. I've been the idiot laying there welding with the dark mask on, completely oblivious to the fact that a raging fire was burning all around me as a result of my ignition source It's way too easy with the welding mask on, and allready feeling the heat from your welding job, to completely miss a fire that has started, and if you get caught up in what you are doing and don't catch a vehicle fire soon enough, next thing you know, it's too late to stop it!

I'm sure you are familiar with that concept allready Just thought I'd throw it out there.

Truckoholic said:

I've been the idiot laying there welding with the dark mask on, completely oblivious to the fact that a raging fire was burning all around me as a result of my ignition source It's way too easy with the welding mask on, and allready feeling the heat from your welding job, to completely miss a fire that has started, and if you get caught up in what you are doing and don't catch a vehicle fire soon enough, next thing you know, it's too late to stop it!

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I set myself on fire one time like that. The blaze was going pretty good by the time I realized I was on fire. Luckily, all it did was burn my shirt up.

grinder+oily rags in a trash can (too close to the work piece)+me not paying attention=?????

worse using an Oxy/ac torch while wearing (apparently flammable soled) sandals and standing on a 2"X2" freshly cut piece of 3/16 frame material.

Common sense goes a long way. If your mama would cringe then you should probably use caution.

Oh,

I never have unhooked anything and never have a problem.

I think removing the tank would cause more problems than it would prevent. Also, in crash tests a full tank is proven to be less likely to ignite. The vapor is your concern. Gasoline will only ignite within a narrow concentration range. No air, no flame period. This is not Hollywood you can shoot a gas tank all you want. It will not explode (even with API or SLAPT rounds). Once out of the tank you might get a good flush if the proper air/fuel ratio is reached with enough fuel present.

Basically, don't drop gasoline through your shop fan while welding and pointing it in that general direction. Think big can of WD-40.

Kids don't try this at home. This is all hypothetical and should never be attempted by anyone. Especially those under the influence of alcohol.

Years ago I was in the shop on the coldest nite of that winter sand blasting the bottom of the gas tank of my 85 Chevy 1 ton crew cab. The plastic tub that covers the bottom of the tank to shield it so it would not get punctured, had trapped the mud from 15 years of traveling and had caused the tank to leak from the rust.

The plan was to sand blast it clean then apply a fiberglass patch.So, I'm on the floor with my small Sears blaster watching the progress and being somewhat concerned that with the poor light under the truck, I can see sparks occasionally.Ah, HECK! Just a few more minutes and I'll be done and besides there's really not THAT much gas oozing from the pinholes an'----- BOOM!!! FLASH!! LIGHTS OUT!!!---------PITCH BLACK!!---SILENCE!!----------------------!!!



WOW!, so-- umm? This is dead!?? HHHMMM??-hey, this aint so bad--yeah, dead's cool-I can do dead!

LOL! That honest to gosh was my first reaction!! The sand blaster nicked the heat lamp I had been using to see with and blew it out!!! No, no fire, no explosion (other than the one in my shorts!)

Finished the repair and called it a night.Repair lasted about ten years-'

Yep-comes under the heading of "stupid human tricks"

Jim

Dropped my tuna fish packet in my lap reading this post. What a mess. Fish and hot sauce every where.

ODw/envy said:

grinder+oily rags in a trash can (too close to the work piece)+me not paying attention=?????

worse using an Oxy/ac torch while wearing (apparently flammable soled) sandals and standing on a 2"X2" freshly cut piece of 3/16 frame material.

Common sense goes a long way. If your mama would cringe then you should probably use caution.

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also too much poly in the tee shirt blend,,,,,,, My friends arm was on fire and he didnt even feel it........I AVOID those POS shirsts.......... cotton poly blend, MY ARRRSE........

Please stay AWAY from ODw/envy..... wearing SANDALS while CUTTING,,,, ......
I could post a long BIG hatefull post here..... but I should research this guy some more,,,, and I will....my opinion dosnt count here,,, ... old burned out guy