Go-to guide on zinc
RHEINZINK Soldering Information
RHEINZINK can easily be soldered. Stripping of the finish is not required to solder bright rolled or blue-grey.
A zinc, chloride-based flux, such as ZD Pro by Felder is recommended. 50/50 or lead-free solders are preferred. The required overlap for a true "sweat" a 1/2”- 5/8”. Rivets may be used to hold the overlap tight, but are not required. If the overlap is not sweated properly, rivets will not keep the soldered lap from failing.
To remove the “Pro-roofing” chemicals such as a standard paint remover will soften the "Proroofing" for easier removal. A wire wheel or abrasive pad can be used as well.