Hi Dave,

In a past life this was used to rework through hole connectors on boards
that were approaching .300" thick and 40-layers, but that was using the
leaded version of the Solder Quik. The contamination of final solder joints
was minimized by re-filling the barrels with the final solder and then
extracting it to dilute the concentration of any residual solder that might
be left behind.

The issue that I have now is that we have a couple of boards that have
lifted connectors that need to be flush to the board. They're 42-pin Samtec
ESW-122-12-G-D connectors that run down the center of the board and,
there's SMT IC's all around them. I don't have an AirVac or anything like
it to rework the connectors. All we have is a heat gun and a solder
extractor. The board is constructed in such a way that it just sucks and
dissipates the heat away from the connectors. We have a very good rework
lady here and she is just pulling her hair out trying to rework these
things. She had to remove a smaller connector and wound-up destroying the
connector and pulling it out pin by pin. That connector didn't have all the
SMT around it that the 42-pin ones do, so I'm trying to help her rework
these boards without pulling a barrel or delaminating the board.

It's only been a few times that I've run across a .062" board that
dissipates heat like this...it's really weird.

Steve

On Tue, May 5, 2015 at 2:54 PM, David Hillman <
[log in to unmask]> wrote:

> Hi Steve - assuming you are using SAC305 solder, then any element(s) you
> "add" to the SAC305 solder joints that has a lower melting temperature will
> allow you to remove the connectors at a lower temperature. Since indium
> melts at 157C, you would lower the melting point of SAC305 to something
> below 217C depending on what the final solder composition ends up being.
> And depending on the alloy phase diagram, you could end up being even lower
> if specific alloy combinations are formed.  The bigger issue is that if you
> don't get all of the "new" solder composition off the pads or the connector
> (if you planned on reusing it) as part of your rework process, then you
> will have unknown solder joint integrity which may or may not be
> appropriate for the product use environment. Food for thought.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
> On Tue, May 5, 2015 at 1:07 PM, Steve Gregory <[log in to unmask]> wrote:
>
>> Hi All,
>>
>> Do any of you know if the Chip Quik Removal alloy (Tin 30%, Bismuth 56%,
>> Indium 14%) works with lead-lead free solder?
>>
>> We have a board here that has to have some connectors reworked that are
>> absolutely a bear to remove and I was wondering if it works with lead-free
>> solder?
>>
>> Steve
>>
>> --
>>
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