best low-temp solder?

Jan 15, 2005 31 Replies

A fair number of surface-mount components (caps and resistors) use silvered terminations. Some of them have an anti-leaching coating over the silver (nickel, or solder with or without silver), others don't. There's also silver plating on some of the RF connectors I use. I'm probably being excessively cautious, but figure that it can't hurt to use a silver-loaded solder and it might save me one or two failures over time.

Apparently this was the first time this particular product was used - and the last as the Zeppelin company did further tests on the paint and never used it again.

N

(and the

HEY! I resemble that statement. What do you mean VERY OLD? Seems like just last week.

-- Crazy George Remove N O and S P A M imbedded in return address

Thanks, a web search was educational. Although one or two sources show only a single melting/solidifying temperature of 179 degrees C for

62Sn/36Pb/2Ag solder, others show a 10 degree C pasty range, with solid and liquid temperatures of 179 and 189 degrees respectively. This range is a bit wider than for, say, 60/40 solder which has an 8 degree range. This would be a disadvantage (probably a minor one) to using the silver-loaded solder.

I found two different sets of data for strength:

Tensile PSI Shear PSI

63/37 7500 6200 32/36/2 7000 7540

and

Tensile PSI Shear PSI

63/37 7600 5400 32/36/2 8600 6600

So it does appear that the silver-loaded solder has higher shear strength, and might have greater or less tensile strength, than unloaded solder. Despite the different numbers, both sources agree that the shear strength increase is about 22%. I wouldn't call that a "very LARGE amount" of difference, but that's certainly a matter of opinion.

Perhaps some people will find that the considerably greater expense, reduced availability, and non-eutectic behavior of silver-loaded solder is worth the modest increase (my opinion of 22% greater) in shear strength. But I doubt that many will. I keep a small quantity on hand for soldering SMD parts which have silver or gold terminations, but am satisfied with 63/37 for everything else.

Roy Lewallen, W7EL

RST Eng> Yes. This little addition of silver adds a very LARGE amount of strength to

************** Oh contraire Pierre - the question was ...."Favorites ?" (look at the Original post) That was mine - because it works for me.. sheesh ! *******************
***** I thought so ******

Next time, just before you hit the Post button, you might want to look at the title of the thread. If he just meant *solder*, he wouldn't have included *low-temp* in the Subject line.

The silver stuff

Regards

Daveb

| > Next time, just before you hit the Post button, | > you might want to look at the title of the thread. | > If he just meant *solder*, | > he wouldn't have included *low-temp* in the Subject line. | >

| so - | what's your "favorite" solder, dude?

Best of British: "Multicore Solders Ltd, Kelsey House, Wood Lane End, Hemel Hempstead"

N

Back when I was doing microwave stripline-on-sapphire, the solder of choice was a mixture of tin and indium (and perhaps a bit of bismuth) that we called tindium. It melted well below the boiling point of water. (No, it wasn't Wood's metal.)

Jim

Many many many years ago, one of my kid buddies built a Heathkit DX-35 transmitter. He couldn't get it to work, sold it to me.

The solder joints were absolutely TERRIBLE. Sooo, I plugged in my Weller gun and remelted one. A puff of acrid smoke erupted. He had used "Liquid Solder". Room temperature.

The good news: he had left all the component leads full-length, so I just clipped everything out, replaced the toob sockets and tiepoints and reinstalled the parts with real solder. It worked, I sold it.

Roby

I haven't seen it yet, but I've heard stories about guys who make spoons of such stuff. When the victim withdraws the stump from his coffee, you're supposed to say, "Man. That's some STRONG coffee".

... and there's no truth in the rumour that Uri Geller buys them in bulk :)

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