using lead ingot instead Sn/Pb blocks

drc_567

Joined Dec 29, 2008
735
... melting a lead ingot in a crucible could lead to lead compound fumes of some sort ... extra hands-on contact would mean skin absorption ...
... not something to take lightly.
 

DickCappels

Joined Aug 21, 2008
5,944
I don't see much of an advantage except in the case of very high current and bus bar is the current (no pun) normal practice in dealing with higher currents than the board's copper can handle is to use busbar or suitably large gauge wire to make the connection.
 

OBW0549

Joined Mar 2, 2015
3,022
Wouldn't it be fine to use these blocks to fill in large traces to provide for more conductivity and thermal management?
No, it would not. And you could have arrived at that conclusion yourself by doing a few REALLY simple Google searches instead of relying on wishful thinking.

The thermal conductivity of lead is less than a tenth that of copper, and its electrical conductivity is only a 14th that of copper. So flooding your traces with lead would not make significant contribution to either thermal management or electrical conductivity.

the melting point is slightly higher than Sn/Pb but I do use a powerful extractor whenever the iron is working.
The melting point of 60/40 solder is 188 °C (370 °F). The melting point of lead is 328 °C (621 °F). And you call that "slightly" higher?

i was going to slice a bit of it off and melt it onto large pads with an iron.
You go right ahead and do that, if it will make you feel good.

But that's ALL it will do, aside from leaving you with a scorched board.
 

Yaakov

Joined Jan 27, 2019
1,604
No, it would not. And you could have arrived at that conclusion yourself by doing a few REALLY simple Google searches instead of relying on wishful thinking.

The thermal conductivity of lead is less than a tenth that of copper, and its electrical conductivity is only a 14th that of copper. So flooding your traces with lead would not make significant contribution to either thermal management or electrical conductivity.


The melting point of 60/40 solder is 188 °C (370 °F). The melting point of lead is 328 °C (621 °F). And you call that "slightly" higher?


You go right ahead and do that, if it will make you feel good.

But that's ALL it will do, aside from leaving you with a scorched board.
This provides some interesting and surprising information about that:

EEVblog #317 - PCB Tinning Myth Busting

Also, the problem with using 100% lead is that it's very poor at wetting, you need the alloy for that.
 

Yaakov

Joined Jan 27, 2019
1,604
There's a funny thing about soldering. The result is an interface with different properties than the metals involved alone. Even though copper, for example, has a much higher melting point than lead-tin solder, the copper dissolves into the solder and forms intermetallic layers with the tin.

This means things change, which can be good or bad. It's also why some solder is better at wetting (60sn/40pb) while having an undesirable plastic range with 63sn/37pb, a eutectic alloy, is less good at wetting but having no plastic state (melting and hardening at the same temperature) makes much better solder joints.

That's why 60sn/40pb goes in the solder pot to tin leads while 63sn/37pb goes on the reel for hand soldering.
 
Top