Questions about Solder

Thread Starter


Joined Sep 18, 2007
Does anyone know the electrical properties of soder?

For example:

Conductivity? Or how many times less conductive it is than Copper?

It's relative permittivity (Er)? I want to calculate the capacitance it creates between two metals.

Thank you.


Joined May 28, 2009
Basically when you solder, you are making a low temperature weld. Considering the small amount of solder used to connect a 30 AWG wire to a 1mm copper pad on a CCA, the amount of resistance is negligible. Typical solder is 60/40 lead/tin alloy with a rosin core, but you will still need paste flux to make the solder melt evenly. Never use acid core solder on electronics, acid core solder is used, for example, to repair automotive radiators and will corrode electronics.


Joined Nov 9, 2007
Basically when you solder, you are making a low temperature weld.
Soldering is not welding.

In welding you are using a joining material that is the same, or very similar, as the parent material (plastic or metal) and trying to create a continuous crystal structure across the joint.

This does not happen when soldering.


Joined Mar 24, 2008
You do get limited alloying where the solder meets the metal, and the solder and the metal must be compatible with each other (with some exceptions). Once the wire material is "tinned" then you aren't going to get it off, not easily at least (some chemistry required).

Gold wire bonding is slightly similar, in that there is some alloying going on.

Because lead has been declared evil and almost as dangerous as mercury (to which I declare BULLCORN!) most modern devices use a form of silver solder (3-5% silver, 95-97% tin). Turns out the new blend grows dentrites like crazy, and is not considered acceptable for military or space use. Meanwhile old fashioned solder is getting harder and harder to find. I bought around 5 pounds of it last ham con I went to, probably a lifetime supply.