Batboard

What is the strongest solder for surface mount speaker-mic jacks: 60/40 or 62 tin, 36 lead, 2 silver, or no lead. What brand and type of no lead do you use?

I use 60/40 most of the time for general service work like soldering a mic jack. I reserve silver for working in rfpa's, and pure lead for soldering lugs on wires (less brittle).

According to a well respected SMT engineer, the no lead should have the highest strength however it also has the highest melting point. No lead SAC 305 is typically 3% silver, .5% copper and the balance is tin. Be careful to not spend too much time on the trace with the iron trying to get it to re-flow. This may be difficult. Liquid flux is your friend!

Use a 60/40 or 63/37 no clean.
I have used Kester or Multicore solders without any issues.

To be specific I usually order:

63/37 CRYSTAL 502 2% .032DIA
Multicore MM00973
Digikey 82-128-ND

It wets well and flows good.

Bob

I use eutectic for most everything except RFPAs for which I use silver solder. Be careful though, if you are doing work that requires you to be compliant with OSHA or manufacturer requirements, lead based solders are now no bueno.

I bought Kester 275 no lead, no clean, 96.5 % tin, 3 % silver, .5 % copper alloy. The box says to apply flux when soldering. Does every joint need flux applied? Is this good general purpose solder?

Yep. You want the flux. Go get some rosin core general purpose solder at Radio Shack. Practice a little bit on something before attempting your surface mount mic jack. You may want to get some solder wick too. Normally I use the heat gun for anything surface mount. But, a mic jack has plastic that could deform. So, I would clean the mic jack pads by applying fresh solder, and then take it off with the solder wick. I'd put the jack in place and tag one or two leads with the iron to keep it there. I would solder all the leads down as carefully as possible, but not get concerned with solder blobs that cover two or more until all the leads are tagged down. Then come back with the solder wick to clean up. Look at them with a magnifying glass and flashlight if you cannot see clear distinct lines between every lead. Brush on some alcohol to clean off the flux, and it's ready to go.