Making a Petrol Tank?

Going to look at building a petrol tank out of possibly copper and soldering the seams, of course the tank would be sealed with something before use
The orginal has a in built in tap, which i have a idea for but will probley leave out,

I after tips for supplies, irons etc. i will make a patern 1st to work out how much i need.

oh and ideas for a petrol cap was thining on the lins of a snug fit brass type like in a 6PB tank?

Cheers Steve

if its any use to you

Its either got to be a orginal or custom made will need to fit in nicely.

Cheers for the offer

Steve