Oatey H-205 water soluble Paste Flux cleans and fluxes most commonly soldered metals including copper, brass, zinc, galvanized iron, lead and tin or copper-coated metals. Fluxing is a critical step in the soldering process. H-205 Paste Flux is lead-free and ideal for copper systems including fire sprinkler, hydronic heating, potable water service and DWV piping. H-205 Paste Flux remains active up to 700 deg F. H-2O5 Flux complies with CA and VT lead content regulations.