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Electronics => Beginners => Topic started by: @rt on March 08, 2016, 01:33:28 pm

Title: Mixing Silver & Leaded solder.
Post by: @rt on March 08, 2016, 01:33:28 pm

Hi Guys :)
When changing caps & such on the board I want to preserve,
is it ok to solder with leaded solder on a board that still has residual silver solder?
for the purpose of a lower molten temperature if there’s a next time?

I’ve done it on protoboard, and the experimental new solder alloy seems to have the characteristics of leaded solder
as far as molten temperatures are concerned.
Cheers, Art.

Title: Re: Mixing Silver & Leaded solder.
Post by: matseng on March 08, 2016, 02:22:08 pm

I've been using Kester solder for a number of years now with 2% silver, 62% tin and 36% lead.  I got this particular roll by mistake and just used in without any special thought.

Wikipedia says the following for this particular mix:

Quote

Common in electronics. The strongest tin-lead solder. Appearance identical to Sn60Pb40 or Sn63Pb37. Crystals of Ag3Sn may be seen growing from the solder. Extended heat treatment leads to formation of crystals of binary alloys. Silver content decreases solubility of silver, making the alloy suitable for soldering silver-metallized surfaces, e.g. SMD capacitors and other silver-metallized ceramics. Not recommended for gold. General-purpose.

So it seems like it's good for SMD, and as equally bad for gold plated stuffs like the common Sn63Pb37 or Sn60Pb40