I usually use rosin flux for soldering or one with rosin core if the solder refuses to stick. I recently found this Goot BS-15 flux, but it says not applicable to PC boards. The label says hobby use soldering paste.
Unfortunately, the contents everything on the back of the container is in Japanese so I can't know for sure what this is intended to use for.
So,has anyone here come across this type of soldering flux and know what this might be used for?
Best Answer
The clue is it says 'weak acid'. This is an acid-based flux, for soldering 'big stuff', cables onto terminals, and it should be suitable for plumbing as well. Clean the joint after soldering.
For PCBs, you should use a rosin-based flux. Most people use a cored solder, without using a separate flux.