Hi, in my more active days I made several replacement fuel tanks for the
engines I found.
Soft soldering having been one of the trade skills of a telephone engineer.
I was lucky to find a sheet metal supplier who had lead coated tin sheeting.
(This might be called Ternplate) This solders very easily!
I learned a lot years ago from a book from Percival Marshal called
"How to work sheet metal"
I hope this helps
My dad taught me about soft soldering. These are the basic rules.
Cleanliness is next to Godliness.
Resin fluxes are OK, but there is nothing like killed spirits (Baker's
Soldering Fluid) for progressively cleaning steel & iron. Heat, dunk, heat,
tin, dunk. Repeat until properly tinned all over.
Temperature is important - too little & the job won't stick, too hot and the
lead goes all crystalline & will not solder properly.
Big irons are better than little ones.
Lead is crap in sheer. Try not to think of it in the same way as brazing,
more like metallic glue.
High tin alloys of lead have a long plastic stage & are best for wiping
Filling ill-fitting joints with solder only postpones the inevitable leak.
All joints should be tight before soldering.
Long joint faces will give long service.
Any tinsmith worth his salt should be capable of soft soldering a steam
engine boiler with complete success.
Finally, cleanliness is next to Godliness!.
All the Specials I built over the years and all my old British bikes always
wore a set of Bowden cables that I'd made myself. Never lost a nipple ;o))
Post hoc, ergo propter hoc!