Welcome to ModelEngineMaker !If you have problems registering or logging in, please use the contact menu option to request assistance.
Not necessarily. The asbestos was quite often painted a dark colour, maybe because it was going to get dirty anyway, and also to stop it fraying.
Radius rods are looking good! Do you have any silver solder wire so you could add a little extra solder for flowing through the joint, in addition to the paste stuff?
You really need tenacity No 5 or CuP's HT5 as they contain something that removes the chromium oxide given off by heating the stainless steel that other fluxes don't. This will apply to whatever silver solder you are using.Harris Black flux will do the same in the US