Problematic spade lug in power supply

On Sun, 14 Sep 2014, Dave G4UGM wrote: To expand on your points some, flux and solder also tend to wick up into the conductor underneath the insulation. With most RMA fluxes, corrosion isn't going to be an issue, but with all these "modern" water-clean and citrus based fluxes, this could be a major problem. Solder wicking up into the wire is likely to be more of a problem as it creates a point where fatigue failure can occur out beyond the connector housing or insulation crimp. In the case of friction fit terminals and contacts, the heat of soldering can also affect the temper of the terminal. This is especially a problem with the really tiny discrete contacts used in modern automotive wiring, and another reason the industry has done a complete 180 on the former practice of crimping+soldering for harness repair as connections have become smaller and more numerous. With coax specifically, soldering also can melt and distort the dielectric. With lower frequency RF (RG58 with a BNC or RG8 with a PL259 for example), it isn't going to cause much of an issue, but with higher frequency stuff, it absolutely can cause problems. Soldering coax connectors without damaging the coax is a bit of an art, and really is something a radio operator should learn and be able to do well, even if they mainly use compression connectors. The bigger issue with coax connectors is sealing them from the elements, and despite what some people may say about the compression variety, both soldered and compression types need supplemental protection from water ingress when used outdoors. WRT to modular connectors (8P8C "RJ45"), one major problem with those are plugs intended for use with stranded wire being crimped onto solid wire. If you look at the plugs sold by a typical computer store, they are more often than not intended for use with stranded wire for patch cables. The bulk of the UTP (cat5/cat5e) network cabling sold in these stores is solid conductor, which is intended to be installed in walls and used with IDC connections. The results of this are easy to predict when you think about how many people who buy supplies from these stores are going to crimp plugs onto bulk UTP cable instead of properly terminating the cable with jacks and using patch cables at each end. The conductivity of a soldered-only connection is also still less than that of a properly crimped connection. This has been well tested in the industry and is just basic physics. The conductivity of tin/lead solder is simply higher than that of the wire and terminal alone, so adding a layer of solder between them will result in a higher resistance connection than if the connection were crimped. With gold plated contacts, you have yet another potential issue, and that is gold embrittlement of the soldered connection. Many smaller discrete contacts are fully plated, and if you solder those, the gold in the crimp area will dissolve into the solder. Depending on the thickness of the plating, there may or may not be enough dissolved gold in the solder to be a problem, but this is still a potential gotcha that many people never consider. The real question people should ask though, is how are these type of connections done in aerospace and full-sized aviation? In those industries, terminals and contacts must be crimped and not soldered. At one time I used to solder or crimp+solder terminals too. I've not done this in decades though.