Most fluxes will bubble and switch mild brown every time they have achieved the proper temperature. Drag the rod or wire of solder content around the sign up for, continuing to warmth the realm indirectly from the alternative aspect from the steel, or a close-by area. Metal Pipe Flux Cored https://automotivemechanics16002.tblogz.com/a-review-of-types-of-solder-to-use-on-aluminum-radiator-41564372