tig brazing a automotive petrol tank

[Piero]

Hi guys.

Still learning my tig.

Spent a while making up this extention for my existing petrol tank.

There was a massive waist of space behind the petrol tank and a card trim that covers it.

I don't have any bending or cutting tools Other than a grinder with cutting disc and a peace of pipe to act as a former.

It's taken a few days to get this far.

So before I cut some round holes in the outer skin of the side of the original tank. To act as baffles and weld this cover over the top.

I really should ask.
It's tig brazing Ok in this situation.

The original tank has gas bazing bits like the tank neck and excite pipe.

I have been very careful to design my extention to avoid any gas braz there is

 

[500e]

Brave shout welding fuel tanks seen tanks that have been steamed then soaked in Trike "C2HCl3" for 24 hours steamed again & still blew up & broke Jims collarbone as he went across workshop

 

[piman]

Hello 500e.

just fill with water and arrange the tank so the work is at the highest point, no need for steam cleaning.

Alec

 

[Piero]

Sorry should have made my self a little more Clear.

The tank is NOT volatile.

My question relates more to the flavour of the filler metal and it's use near petrol.

Gas and tig filler wire being different

 

[500e]

Tell my mate that broken collar bone & burns when it exploded.

 

[langy]

Sorry should have made my self a little more Clear.

The tank is NOT volatile.

My question relates more to the flavour of the filler metal and it's use near petrol.

Gas and tig filler wire being different

It's entirely feasible but with the cost of silicone bronze rods I would use good old A15

 

[hotrodder]

I would've guessed that silicon copper TIG wire would be similar or even less prone to galvanic corrosion than the (origional) copper zinc brasses used for oxy fuel brazing but http://ttypes.org/ttt2/ethanol-blended-fuels suggests otherwise. The E10 used in that test is more corrosive and more prone to phase seperation than E5. While welding would sidestep the galvanic corrosion thing whatever you do will do will locally damage any terne coating inside the tank which is vunerable to modern environmental fuel blends anyway according to many sources. I don't doubt that many of those sources are overstating things at least a bit just like they did with the demise of leaded petrol but a fuel tank sealer when your finished would be cheap insurance

 

[Piero]

Thanks langy and hotrodder

Yes silicone bronze is silly money. But I had bought a half pack before to weld in a new type full outlet.

That's how I know the tank is not volatile.
I fire lighter on a long tube done from behind a wall will test any tank lol

I was intending on using a tank sealer Afterwards anyhow.

Only I wasn't sure what one. And if they stand the test of time

 

[Piero]

Fuel outlet not full out let

 

[Mr shiney]

Why not just weld it?

 

[Piero]

It's only 0.8 mm

Weld it with a 15 or tig braze it. It's just the same work.

Only less chance of blowing a hole and or warping the thin sheet steel

 

[lchris21]

not much help with the question, but nice metal bashing with basic tools....

 

[langy]

It's only 0.8 mm

Weld it with a 15 or tig braze it. It's just the same work.

Only less chance of blowing a hole and or warping the thin sheet steel

I personally wouldn't want a fuel tank that thin, it should still be easy to weld with 1mm rods, by the look of the size of your tacks your gonna use quite a few rods.

 

[Piero]

Yeah I know. quite a few indeed.

The original tank was made in 0.8 gauge.

Guessing to add with pressing it

It sits well inside of the car. Well away from anything.