Siver soldering bandsaw blade

Hello Not having great luck. I have some rolls of bandsaw blade stock. Any hints or tips greatly appreciated. Can flux go bad or get contaminated? It seems the solder melts but doesn't have that nice flow , but instead just lumps up into a nice cold solder joint. I cleaned the joints well , but when I apply the heat til it gets red hot I get this black gunk gathering at the ends of the blades. Is there a different flux for non ferrous & ferrous metals? I've silver soldered before with great success.Thanks. ron
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One way my dad use to solder blades is prepare the ends of the blades with a tapered lap joint. Apply flux and a piece of flat silver solder, then using a set of soldering pliers that have been heated to red hot with an acetalen (sorry for spelling) torch, then gripping the band with the pliers.
His pliers where about 18" long, (end to end). The heating end was 1/2" square iron stock.
Should only take 30 secs or so to solder the joint.
As for the black gunk, it sounds like you are getting contamination from your torch.
Hope this helps. If needed, I could probably get a pic of the pliers. Just let me know.
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James
Ronald Murray wrote:

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James wrote:

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I believe flux can go bad. I've not soldered B/S blades, but this past winter I was intalling a new bath & shower control valve. The flux I had on hand caused the solder to behave exactly as you described. I bought a new container and the soldering went smoothly and flowed just as you would expect.
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