Hacker News Reader

Comment by superseeplus | Hacker News Reader

How harmful is lead in solder used to join copper pipes? Lead free solder was mandated only around 1986, so presumably there are a lot of copper pipes around using solder containing lead.

View on HN

The exposed/wetted area of a soldered joint is pretty damn small and I’d expect those 40 year old joints have reached an acceptable steady state by now.

That’s not an excuse to use leaded solder on supply pipes as plumbing with lead-free solder is perfectly easy, but I don’t sweat* the old copper pipes in my 1920s home.

https://www.copper.org/applications/plumbing/techcorner/sold...

* That pun was inadvertent.

I'd imagine the extremely tiny portion of solder exposed to the water supply is nothing compared to the "lead-free" brass fittings which were permitted to contain various non-zero amounts of lead depending on the year, and still do.

But with most things, the dose makes the poison.

you have two problems with new formulations though. one is lead-free solder seldom works as well as the box claims. two, antimony is somewhat concerning from a toxicity standpoint though i'd say less than lead

i wonder if we don't just quit and go to brazing all joints. rod is pricier than solder and takes more heat but probably less toxic and certainly more dutable

Tin/silver soldering (~95/5) would probably be better than brazing for water supply piping as brazing will tend to anneal the hard drawn copper tubing, which isn’t desirable from a strength standpoint.

non-zero harm but it's necessarily a lot less than making the whole thing out of lead. think about the difference between a square inch of lead exposed per joint versus many square feet. not a one-to-one comparison since the shear stress at a joint will be higher, but such a relatively smaller area it will have a relatively tiny impact.

Reply on news.ycombinator.com