Soldering the off grid hot water system

Today we crossed the finish line on the soldering marathon of our hybrid solar thermal and wood fired hot water system.

I’m really liking my new Ridgid 1/2- and 3/4-inch rotary tubing cutter, much better than the old style cutters. Once I have dry fitted the entire assembly I identify which points will be easiest to solder in place and then mark the orientation of the rest of the fittings with a sharpie marker and break the whole thing apart to solder the separate subassemblies on the bench.

To deburr the inside of the cut ends I use a pencil-style deburring tool.

A cheap fitting brush cleans the outside of the pipe ends and the inside of the fittings.

Water soluble acid flux isolates the joint from oxidization while it’s heating up.

I use mapp gas (not propane) and a trigger style torch head to heat the fitting (not the pipe!)

…and of course silver solder because I can’t afford to drink lead and get any dumber than I already am!

Once the subassemblies are complete we use a Scotch-Brite pad to scrub them with a mixture of salt and vinegar to make them pretty again.

Finally we wipe them down with alcohol to get rid of the sharpie marks and any remaining crud.

After that it’s just a matter of soldering the remaining connections in place and trying not to set the house on fire. Stay tuned for the pressure test….


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