There should be a slight gap amongst them for the solder to movement together, but retain this to one/25" (one mm) or fewer. In case the pieces will not suit collectively smoothly, you have got to make the joined places smooth via sanding or bending. Furthermore, solder can be employed https://mariovqnnb.alltdesign.com/not-known-factual-statements-about-types-of-solder-to-use-on-aluminum-radiator-47198559