Types of lead-free solder

[Tom Del Rosso]

Still no industry standard? Which alloy do you like for repair of new
boards?

 

[Paul Drahn]

Still no industry standard? Which alloy do you like for repair of new
boards?

If you mean wire solder, we use pure tin. If you mean paste, it is SAC?
and I don't recall the number.

Paul

 

[Tom Del Rosso]

If you mean wire solder, we use pure tin. If you mean paste, it is
SAC? and I don't recall the number.

Wire. But pure tin, not even 0.3% copper? I thought that was only for wire
bonds or something.

 

[Tom Del Rosso]

Of course, I
don't think that there is any such requirement to maintain the
original certification on your side of the pond. So I would say, go
right ahead, and use 'proper' solder to carry out your repairs, but
suck or wick as much of the lead-free solder off the joint as you
can, before remaking the joint.

Will there not always be a residual film of the original solder, and would
that not cause a crack along the entire interface?

 

[N_Cook]

Will there not always be a residual film of the original solder, and would
that not cause a crack along the entire interface?

It is the absence of lead rather than presence of tin that is causing the
problems, you have tin in both leaded and lead-free solder. It is the lead
that gives the forgiveness, perhaps someone knows the technical rather than
folksy term for this

 

[Tom Del Rosso]

It is the absence of lead rather than presence of tin that is causing
the problems, you have tin in both leaded and lead-free solder. It is
the lead that gives the forgiveness, perhaps someone knows the
technical rather than folksy term for this

Sorry, I misread your previous post. I was thinking of the opposite. If
the joint used SnPb originally you would never be able to remove all the
lead, so could you use Pb-free after cleaning?