[Harrymac]

Hello Stephen,

Find a roof plumber, one that can still solder.
He will need an electric soldering iron, (a big one) to have
enough heat.

He first needs to thoroughly clean the area to be soldered,
then he will need to 'tin' the area, this is soldering the area
all around the pipe so that you can see that it is all clean
and tinned, he can then solder the pipe to the tank and
build it up.

This process can also be used to solder fittings for hoses
into the tank. I have used gas soldering irons for the same
purpose, the big thing is to remember to turn off the flame
BEFORE taking the soldering iron to the fuel tank. I do not
recommend this method.

Good Luck,

Harry.