I have done both the exhaust till the tank is too hot to hold and its counterpart a hot air gun.
Also the tank filled with water method
This is also a very old thread but worth a mention.
Solder should really be lead wiping rather than soldreing particularly if there are lots of pinholes.
If you go that way the trick is to strip all paint off, degrease then apply a mix of oxide & reducing flux called Panel Butter.
I know Eastwoods still sell it.
That will leave you with a tinned tank that will take solder beautifully either by direct flame or big soldering iron.
I have also done them with silver solder using my Henrob Torch, now called DHC 2000 .
Kent , the tin man ( google him ) does a much cheaper more conventionally shaped torch for those who find the pistol grip Henrob difficult.
I never liked the idea of bronzing a tank.
Bronze has a bad tendency to crack from vibrations
With the Henrob it is possible to weld pin holes with steel, done it many times, it is just a case of getting fine enough feed wire.
I use thin tie wire which is handy because you can put the coil ( donut to some ) of wire over one wrist and feed the wire in as needed.
Practice on some in cans first .
Once you can weld them without blowing holes you are there.
I remember seeing this method of tyre fitting on TV,Top Gear I think, it was being used on a huge FWD tyre in Iceland but I've never seen it used for bike tyres though.
