I've had good luck with the kester 62/36/2% silver stuff, which is
eutectic.

Many many years ago, I had some luck with a indium-bismuth solder paste
in syringes from Indium Corp. Haven't fiddled with any of their stuff
since then.

Radio Shack sells a bag of little peices of tape-form stuff. Never got
it to work well.

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