Flux is designed to improve electrical contact and mechanical strength in solder joints. There are mainly two types of flux cores. Acid core and rosin core. Acid core is used for plumbing and rosin core is used for electronics.

Also Know, is there a difference between electrical and plumbing solder? Plumbing solder uses an acid (it’s also know as acid core solder). The acid will corrode electrical wiring, so electrical solder uses a milder chemical. Electrical solder is also called rosin core solder because the chemical used to be pine rosin.