OATEY 29024 Safe-Flo® 1/2 lb. Silver Wire Solder

Safe-Flo silver wire solder is a copper, bismuth, tin and silver alloy that meets ASTM B-32 and the requirements of the Safe Drinking Water Act, so it's the solder to reach for on domestic potable water copper. That's the spec an inspector or a facility maintenance lead will ask for on residential and commercial water piping.

No. Safe-Flo silver wire solder is not recommended for aluminum. It's a tin/silver type alloy meant for copper and copper alloy joints. For aluminum you need an aluminum-specific brazing or soldering alloy and its matching flux, not this wire.

This is a solid solder wire, not a flux-cored or acid-core product, so you flux the joint separately. Use a water-soluble or petroleum-based tinning flux rated for potable water, brush the cleaned tube and fitting cup, then feed the wire once the joint is up in the 420 to 460 degree F melt range. Skipping the flux on copper gets you a joint that looks filled and leaks under pressure.

On any line feeding potable water, the lead bearing alloys are off the table, and Safe-Flo meets ASTM B-32 and the Safe Drinking Water Act requirements, which is what makes it the correct pick for a repair in an occupied property. Lead free silver alloys like this one run hotter and set faster than old 50/50, so you tend to heat the fitting rather than the wire and pull the flame the moment it draws in. For non-potable work, heating loops or drainage, this solder still works fine, there's just no code reason to insist on it.

It's 0.117 inch gauge wire. That's the common all-purpose diameter for hand soldering copper tube, thin enough to feed into the cup of a 1/2 inch fitting without flooding the joint and heavy enough that you aren't feeding half the spool into a 2 inch fitting.

Safe-Flo silver wire solder has unlimited shelf life. A roll that's been rattling around a service van or sitting in an MRO crib for a couple of years still solders the same. Flux is the consumable with a real shelf concern, not the wire.