02-06-2017 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,657 Joined on 10-12-2006 Post #: 26 Post ID: 22957 Reply to: 22956 Flux Is Acid You need acid (flux) to flash clean the metals as they are being soldered and prevent a "cold joint"/poor bond that not only spoils transmission initially but it oxidizes and worsens faster over time. If you've used enough flux for a good joint (especially with thicker/heavier gauge materials), then you will have acid and also acidic oxides on the metals after soldering. No matter visually "clean", the metals need to be chemically neutralized to stop oxidation and/or electrolysis happening under the shellac, which only works, after all, to keep oxygen from a "perfect" soldered joint. No sense putting shellac over a corrupted joint Paul S

02-06-2017 Post does not mapped to Knowledge Tree rowuk Germany Posts 454 Joined on 07-05-2012 Post #: 27 Post ID: 22958 Reply to: 22957 Vintage connections better Remember wirewrap with the sharp cornered posts? The amplifiers that I built that way are still noise free after 40 years. 20 turns or so per post work just fine and those connections can be shellacked. Whenever I feel blue, I start breathing again.