[sdiy] Solder won't stick to old PCB

[Ingo Debus]

Am 28.09.2009 um 18:15 schrieb Graham Atkins:

> If you look at the various soldering eqpt manufacturers sites about
> the use of lead free solders, the melting point is typically a fair  
> bit
> hotter than for leaded solders.

True, but usually the soldering iron is way hotter. I usually set the  
Weller iron to about 350°C (scale of the pot at the soldering  
station, probably not very accurate). Sn95,5Ag3,8Cu0,7 has a melting  
point of 217°C; standard leaded stuff like Sn60Pb40 has 183 - 190 °C  
(numbers from Felder catalogue).


> Ingo, your iron was probably too
> hot to start with, the solder you describe will definitely have a  
> higher
> melting point than your usual 60/40 lead alloy.

I didn't say I was having any problems with soldering :-)
However I do have a problem: when using a very fine tip, the solder  
sticks well on component wires and PCB traces but not on the tip. It  
seems these very fine tips you only need for SMT work wear out really  
quick. The Weller "tip activator" helps a bit, but only for a short  
time, and it smells very bad...

No this is not a lead-free solder problem. It happens with leaded  
solder too.

Ingo