..which include crevices, standard plumbing flux and when I've experienced luck with most solders, four% silver bearing solder is more powerful Over time...kinda pricey tho... I had Harris solder on hand at some time so no large offer for me but high-priced if you don't need the toughness for off https://spoiler-car-types74951.ageeksblog.com/26832495/new-step-by-step-map-for-types-of-solder-to-use-on-aluminum-radiator