How to remove solder from pins?

[yararyus]

Hi there people,

As you can see from the title I'm trying to remove solder from pins. I put my pins into a beaker and poured HCl (20%) and I waited 2 days but no solder removal process happened. The only thing that happened was the shininess of the pins gone. Now, my pins still have solder at their ends, and shininess of yellow parts faded away a bit. I wonder what is the problem? Should I have to use HCl with a high concentration like 35% or should I heat my 20% HCl a bit (in order to increase the concentration of HCl)? Also fading away of shininess is the removal of polish of pins right?

 

[FrugalRefiner]

Should I have to use HCl with a high concentration like 35% or should I heat my 20% HCl a bit (in order to increase the concentration of HCl)? Also fading away of shininess is the removal of polish of pins right?

Your 20% HCl should work. When I make stannous from tin metal, I dilute my 32% HCl. I do add a bit of heat to get the reaction going. Once the reaction starts, you can remove the heat.

You can not increase the 20% concentration with heat. That's about the azeotrope for HCl, so the HCl and the water will evaporate at about the same rate.

The loss of shininess is probably just some of the base metals cementing back out on top of the gold.

Dave

 

[g_axelsson]

It could be nickel plating below the solder.

Göran

 

[kurtak]

do you know how old the pins are ?

I ask because if the pins are old(er) pins the solder could also be the old 50/50 lead/tin solder rather then the knew(er) tin/antimony solder

Kurt