Re: gEDA-user: OT: lead-free question

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Sun, Mar 05, 2006 at 03:09:55PM -0800, Steve Meier wrote:
> Well I don't expect it to explode ;) And, I think we have already
> established that all electronics related technical questions are
> exceptable debate foder for this list. So drop the appology and tell us
> afterwards what your experiences were.
> 
> The issue, I think, is can you solder the lead free device to a board
> with a lead based solder and make a good conduct?
> 
> I suspect the answer is yes.  If it doesn't seem to work use some more
> flux. Inspect the solder conection in the typical method looking for
> cold solder joints.
> 
> Lead free seems to indicate that the device not only doesn't contain any
> significant lead but that it also can withstand the higher temperatures
> that lead free solders require. So if you can get a lead based solder to
> adhear to the devices pins then the lower solder temperature shouldn't
> be a problem to the device. If the device is in a solder ball based
> package such as a BGA then you might have to cook the board with the
> device at a higher temperature in order to get it connected. If this is
> the case and you are including older devices on the same board then the
> increased temperature might damage the older devices. In this case a
> stratagy of cooking the board with just the non-lead parts first then
> attaching and re-cooking the board with the lead based parts might be
> the right idea.
> 
> This issue of visual inspection for cold solder joints is going to be
> more complex with non-lead based solder. This is do to all solder joints
> looking shiny (as i recall from the seminar I attended) even if they are
> bad with the silver tn based solders.

For me with Sn99Cu1 the joint look always matte, no matter if they are
good or bad.

CL<