Tinning on old PCBs

From: Ethan Dicks <erd_6502_at_yahoo.com>
Date: Wed Dec 19 23:59:00 2001

--- Louis Schulman <louiss_at_gate.net> wrote:
> My questions is this: Is the copper itself sufficient to carry the
> currents, or is the tinning required to reduce
> resistance?

I'm not sure it has anything to do with resistance.

> Or, putting it another way, is the tinning required, or is
> it just to assist in attaching components?

Tinning _does_ help with attaching components.

> Or, putting it one last way, do I need to re-tin the bare spots?

I would. Carefully.

I think the biggest benefit gained from tinning spots that _don't_
have components attaching to them is that bare copper traces could
oxidize all the way through, especially if they are exposed to a
corrosive agent (from ammonia to human sweat). I think tin oxides
are more protective of the underlying metal, much like aluminum
oxides.

I am not a chemist or metallurgist, but I _think_ it works like that.

-ethan



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Received on Wed Dec 19 2001 - 23:59:00 GMT

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