Florida high-rise copper-plated stainless steel water piping failure

Copper was expensive. When copper got even more expensive in the 1970s, Allegheny Ludlum Steel said, stainless steel is very good and we can make it thin wall and cheaper, but we have to have something that the plumber can solder to. So that's another material property in the material selection. You can't solder to titanium. It's got this protective oxide. There is no flux that will eat away the titanium oxide. So you can't solder to a titanium pipe. Stainless steel has a chromium oxide; you can solder it, but you have to use pretty aggressive chlorides which can pit the stainless steel. So they decided we'll just plate the copper — put copper plate on the outside, and now you can solder to it just like you do a copper pipe.

Early-1970s stainless industry response to copper price spike; copper plating with holidays caused focused galvanic attack; 40-story Florida condo perforated within 18 months. Tom did splash-line tests as junior faculty at $15/hr.

I've seen pits — I talked about the pits and my mother-in-law and the dinnerware. My thesis advisor had a situation over 40 years ago. When copper prices went up in the early 1970s, the stainless steel industry thought they had a great solution: use stainless steel for piping in a home. The problem is you can't easily solder to stainless steel unless you use a very aggressive flux. So they decided to plate the outside of the stainless steel with copper, and that way they could solder to the copper. That sounded great.