I saw these pictures of a homemade immersion chiller on another site and the first thing that stuck out were the soldered joints that would be sitting in the boiling wort. Anyone know if that’s safe to do? My immediate reaction was “danger wil robinson!” but I wasn’t sure.
It is safe. The main issue is overheating the copper so the solder doesn’t flow. The work in the pictures probably would have a plumber gritting his teeth at the waste but looks thorough enough…
The only risk I can see is if really old solder was used - it may contain lead. Still; there likely isn’t enough exposure time in the boiling wort for leaching to be a concern considering the pH is in the 5+ range.
If you use solder on brewing equipment and it will be in contact with wort, be sure it is “lead-free” solder. New solder will be lead-free, which is what I used on my IC.
Isn’t there a type of flux that must be used if it’s for a drinking application?
I’m not aware of any special flux, but most of the flux will burn away during the soldering process, and what is left behind is normally wire-brushed away.
It’s always a good idea to thoroughly clean soldered joints and seams before using for the first time. A good spritz of star-san on those parts that won’t be submerged prior to dropping in the kettle doesn’t hurt either…
One can purchase a lead test at a hardware store. I did when I purchased a wort chiller off of eBay that claimed to have used silver solder. It is just as easy as wiping a moist cloth from the kit. If it turns color there is lead present. Mine was free of lead.