Any large hobby shop might have the K&S metals tube sheet and solid displays. Micheal's, Hobby Lobby, as said Home Despot, Highes have it but are a little pricey. Tractor supply stores, some welding supplies may still sell the gas welding rod or TIG rod buy the pound. Aluminum, Bronze, stainless and copper.
You can buy wire and remove the insulation from it. The trouble with using pop cans,beer cans is both the inside and outsides have a resin heat set coating to prevent counterfeiting and the transfer metal taste to the product. It is a pain to remove other than abrasive means.
Some sheet metal shop will see the drop and scrap copper, aluminum.
And of course there are on line sources.
A caveat on the flashing and other sheet stock, it will have either an oily coating from manufacture or a protective coating to prevent or slow corrosion, it will need to be removed before adhesive is applied and the surface Scuffed up so there is some tooth for the adhesive to grab. DNA or acetone will work.
:clown: