pickling copper

[BMyers]

If you are following along, I am building a cracker locomotive. I am at the boiler build stage. How often in the fabrication of copper parts should I be pickling ? Or do I do it once after I am done with all the soldering ?

 

[Kermit]

It is to remove the oxidized surface layer(pickling), so as long as the future soldering,brazing is in an area that is still oxide free, pickling would not be needed. The flux, if it is not an active one, will not remove oxides, so steel wool might be used to avoid the wait for a pickle bath. If the area has gotten hot and discolored pcikling works best to clean it for further brazing.

Multiple dips in the acid bath won't hurt, especially if you use a gentle one like citric.

 

[shred]

I pickled after each silver-solder operation. Solder up whatever all needs soldering this time around, wait for it stop glowing, dunk it in water to cool, then into the pickle for a while. Fish it out, drag it back through the water tank to wash off the acid and inspect the joints. On my Cracker, I'd either make some little parts or go surf the web for half an hour or so.

 

[Loose nut]

One problem you can have with pickling between solderings is that there can be pickling residue trapped in the joints and that can, but not necessarily, cause problems.