Safest way to weld inside a gas tank??????

I need to add a baffle inside, and am thinking of filling it with water for a while to eliminate fumes. Any thoughts on this?
I can't do without the baffle, everytime I slow down, fuel sloshes forward away from the pickup tube / pump.

maybe any fuel-proof epoxys out there? Baffle is only a 2x4 inch hinged piece....

THANKS!

 

wash it out, then purge with inert gas while welding.

 

no weld...try some fuel cell foam.....dont know if you con get it thru the pick up hole..just a thought ???

greazy hubcapz cc east tn

 

I've filled them with soapy water, then flush, flush, flush with hose in the tank and just let it run. After that, shop vac hose over a tailpipe and into the filler, some guys purge with CO. I'm not blown up yet...

The stainless tank under my roadster isn't baffled, and I've got the same issue. I was thinking of stuffing some fuel cell foam into it, if I can get it compressed and shoved in the sending unit hole, I don't want to cut the tank open.

Brian

 

Way back in the 70's when I was in high school, I worked at a radiator shop that did gas tank repair. The method to safely work on tanks was to first punch a small hole in one upper corner of the tank and upend it with that corner down to drain all the fuel out. Next was to put about 1/2 a gallon of caustic solution from the boil out tank in and shosh it around a few times. Then, stick a hose in the tank and let water run to rinse it out for about 20 mins. The tank was drained again ready for the torch. the last step was to shove the tank under the big tank that was used to leake check radiators, grab the torch, turn face away and stick it in the tank. No boom- good to go. The final step was to solder a penny over the hole punched in earlier. This was back when the caustic was really caustic, & the radiator repair technicians got lead poisioning. I was just the r&r guy.

 

First time I saw someone welding a gas tank. The guy had a hose hooked to the exhaust on his welding truck going into the gas tank he was welding. ( Inert Gas ) like mentioned above.
Not saying I would do it. I have seen to many accidents from stuff like this. I would find something else.

 

And when a penny was copper vs today's 98% zinc.

 

I think the first thing to do is check for a drain. A lot of old tanks actually had pipe plug drains. My Buick does and I'd be really pissed if someone punched a hole for no reason.

 

After emptying the tank and letting it dry thoroughly, pipe in exhaust gases from any running vehicle until the tank is warm to the touch. (Some extra time doesn't hurt either!)

This is the method we used back in the day in the motorcycle biz. Those old Triumphs & etc. were pretty good shakers and split a lotta gas tanks. Never had a problem.

 

water will not eliminate the fumes and also as soon as you heat the metal up the pores will open and more volatile vapors will be present. you need to go to the grocery store and buy about 2-3 blocks of dry ice, crush it with a hammer and break it up and disperse inside the tank, it will evaporate and fill the tank with an inert gas co2 and push out the volatile vapors as well, then weld it and be safe and happy. dont dilly around while welding, spot it and be done.
I used to do storage tank removals for a living, hundreds and hundreds and all were torch cut up using this method of degassing.

 

this method does indeed work as well, basically filling the interior atmosphere with an inert gas. if the tank is open enough to get access for welding, you really need to make sure you contain the inert gas in the tank to create the safety blanket you will need

 

The foam will cause you alot of problems after a couple of years when it starts to come apart, if you are afaid to weld on a gas tank, you can use permatex gas tank repair adhesive between the the baffle, and tank along with blind sealing pop rivits to make sure it stays put.
http://www.mcmaster.com/#sealing-blind-rivets/=611b3z

 

All good ideas! I think I'm going to drain it, wash it out with water, and run a hose from my diesel truck exhaust into it for a while.
Its a fairly new custom made tank, no drain valve. One or two quick spot welds is all I need.

 

I think I'll try the dry ice trick

 

I saw a deal on ping pong balls or something in your tank for a cheap baffle? I'll look. Lippy

 

Wow. All these ideas to safely weld a tank, yet not one idea on the safe way to do the baffle.

Solder. No flame, no boom. Solder with an iron like they did "back in the day".

And those Triumph tanks?? Early ones were - ready for it- soldered!!

Cosmo

 

I don't believe I've ever seen a soldering iron that would be large enough to accomplish what you're suggesting. Not saying they don't exist, just that I haven't seen any large enough to keep up with the heat loss that a piece of sheet metal that big would dissipate.

As far as the early Triumph tanks, sure they were soldered, but they were likely soldered with a torch, just like bodywork leading is done, and was "back in the day"......

 

They sell tank sealants, a 2 part mix if i'm not mistaken. Immune to gasoline and won't break down, they're meant to patch a pinhole or crack with gas still in the tank.

I remember the monster garage episode (eek ) with the guy from blastolene couldn't weld the gas tank properly after bragging he could weld better than JJ and had to use it b/c he put gas instead of water to test it hahaha

Do a test with some scrap metal to see if it will work as an epoxy?


Safest way to weld on a tank is to not weld at all.

 

I welded a sump to the gas tank in my F-100. I rinsed out the tank with dish soap and water probably a half dozen times until the smell of gas was gone. It welded up just fine.

 

Pardon my stupidity, but how can you insert a baffle inside a tank without taking it apart, let alone get in there with a welder to hold it in place?

 

By cutting an access hole in the top big enough to drop said baffle in, with a couple 1/4" holes in the flange, spot welding thru the holes to the floor of the tank, then welding the access hole piece back in? That's how I would do it, but, that's just me...

Brian

 

Actually, my sender / pump hole is right above where I need to be. Pretty easy access.

 

I just took mine to the car wash, spent 3 bucks on soapy water and 1 buck on rinse, then welded with no problems. Wouldn't hurt to put a flame over the inlet, from a bit of distance, before you start.

 

Make a slit in the tank where you want it, drop the baffle in the slot, weld the slot, cut it off.

 

I would make sure you're really high. If there's an explosion you'll be more supple and able to absorb the force.

 

Even better!

 

The safest way would be to pay someone else to do it. Some guy near my house blew himself up a couple years ago welding on a gas tank.

 

Another method to clean out the residue, that I have used, is a combo of hot water and tri-sodium phosphate (otherwise known as TSP). For anyone unfamiliar with it, TSP can be purchased at hardware or paint stores. The combination of the hot water (really hot) and TSP really cleans the metal. I still like the many ideas of using a gas to purge the gasoline fumes as well. Good luck

Joe

 

We have done the Dry Ice thing more than a few times with great results - but it still scares the shit out of me every time, waiting for the boom.

 

Some interesting theories coming out of this one.I wonder if this is why Ryan is calling some of us Grenade Inspectors?