Any recommendations for soldering electronic circuit boards. I am wondering if the lead free is better or the clear flux solder.

Here is some examples from the local Radio Shack

.05" ROSIN CORE SOLDER 64-6 $4.99
.05" Rosin Core Solder (60/40 Formula) 42.5g (1.5 oz.).

SILVER SOLDER 64-13 $5.99
Silver solder. High grade solder for surface mount devices. 62/36/2% formula. 0.022". 42.5g (1.5 oz.).

HI-TECH SOLDER 64-15 $3.99
Hi-tech solder.63/37% formula. .050", 42.5g (1.5 oz.). Specifications: ·Melting Point is 183 degrees C


CLEAR FLUX SOLDER 64-18 $4.99
Crystal flux solder. Clear flux solder. 60/40% rosin core. .063", 56g (2 oz.). Great for projects and design work. Holds shape and dries smooth. Provides better looking results, no discolourations.


LEAD-FREE SOLDER 64-27 $7.99
Lead-free solder. 97% tin/3% copper. For fine electronic soldering. 0.50". 56g (2 oz.).

 

I haven't enough skills or experience to offer comments that would be of use in a commercial application. For myself the decision on which solder to use would be based on how much effort it would take to make an electrically efficient connection, how little damage would be done to the part or board and the robustness and reliability of the connection. I suspect that each of the solders you have listed will do those things to greater or lesser degrees - depending on what you are doing.

A friend of mine who repairs commercial radios told me to be sure I use a silver bearing solder when soldering the tabs of a power RF transistor to copper foil. Apparently non-silver bearing solders are known to degrade in this application.

If it means that much to you then experiment and see if you see or measure any differences. You'll either find a preference or find that in your situation there is little difference. They will probably all work if made for your application.

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stevez