Your solder may be no clean

[Jeremiah McCarthy]

"Apparently some government agencies and their contractors like to see excess
rosin flux removed and train their people to do so. I'm not sure why they do
that, but in the environment in which Elecraft rigs are capable of being
used this is completely unnecessary."

        (a) all government work must be inspected and "sold" to QC...QC demands integrity and cosmetics..
        (b) Under high magnification, flux that does not appear to the naked eye stands out and can hide flaws...
        (c) a lot of government work requires conformal coating...The coating will not adhere to flux coated joints
        (d)  cosmetically, it looks better and requires very little effort to do...

There seems to be an opinion regarding solder that "eutectic" means the ability to go from a liquid state to a solid state without passing through a plastic state..."Eutectic" means that the ratio of the base metals of the alloy are formulated to give the lowest possible point of solidification, usually lower than the point of any of the base metals used, and has nothing to with the presence or absence of a plastic state...

Jerry, wa2dkg
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[David F. Reed]

Jerry,

Thanks for the brief explanation of why the NASA solder specifications
are what they are, and the explanation of eutectic.

If anyone wants to know more about it,
http://en.wikipedia.org/wiki/Eutectic does a fair job, and includes a
phase diagram and is a good reference.

Jeremiah McCarthy wrote:

>"Apparently some government agencies and their contractors like to see excess
>rosin flux removed and train their people to do so. I'm not sure why they do
>that, but in the environment in which Elecraft rigs are capable of being
>used this is completely unnecessary."
>
>        (a) all government work must be inspected and "sold" to QC...QC demands integrity and cosmetics..
>        (b) Under high magnification, flux that does not appear to the naked eye stands out and can hide flaws...
>        (c) a lot of government work requires conformal coating...The coating will not adhere to flux coated joints
>        (d)  cosmetically, it looks better and requires very little effort to do...
>
>There seems to be an opinion regarding solder that "eutectic" means the ability to go from a liquid state to a solid state without passing through a plastic state..."Eutectic" means that the ratio of the base metals of the alloy are formulated to give the lowest possible point of solidification, usually lower than the point of any of the base metals used, and has nothing to with the presence or absence of a plastic state...
>
>Jerry, wa2dkg
>

73 de W5SV, Dave
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[Don Wilhelm-3]

I checked the referenced link, and it contains the following statement: "The
eutectic point is the point at which the liquid phase borders directly on
the solid ? + ? phase, representing the minimum melting temperature of any
possible alloy of ? and ?."

As I read that the liquid phase BORDERS on the solid phase, it certainly
says to me that the plastic phase is absent (and that is the most important
point for soldering IMHO).  The fact that this also represents the lowest
possible temperature for solidifacation also is true, but not the main
emphasis for a soldering application - we usually use a higher temperature
than the absolute minimum required.

73,
Don W3FPR

> -----Original Message-----
>
> Jerry,
>
> Thanks for the brief explanation of why the NASA solder specifications
> are what they are, and the explanation of eutectic.
>
> If anyone wants to know more about it,
> http://en.wikipedia.org/wiki/Eutectic does a fair job, and includes a
> phase diagram and is a good reference.
>
> <snip>
> >There seems to be an opinion regarding solder that "eutectic"
> means the ability to go from a liquid state to a solid state
> without passing through a plastic state..."Eutectic" means that
> the ratio of the base metals of the alloy are formulated to give
> the lowest possible point of solidification, usually lower than
> the point of any of the base metals used, and has nothing to with
> the presence or absence of a plastic state...
> >
>

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