Solder Problems (PDP-8/m related)

From: Joe <rigdonj_at_intellistar.net>
Date: Fri Dec 3 20:19:10 1999

At 02:32 PM 12/3/99 -0800, you wrote:
>>Tony Duell wrote:
>>> Another warning. There's a stuff called 'silver solder' used by
>>> engineers. This is _NOT_ the same stuff at all -- it's high melting point
>>> (you can use it on small steam engine boilers, etc). I'm not sure it even
>>> contains silver.
>>
>>I believe it does contain silver indeed. It is _very_ expensive.
>>And you need acethylene+O2 in order to use it.
>
>I have a spool (1 lb?) sitting behind me of 96 SN silver solder, wasn't
>"too" expensive and melts with a slightly hotter tip in my weller.

  That's the same kind of stuff that they sell here for soldering copper
water pipes. NO LEAD ALLOWED! The last time I checked it costs about
$16/pound. That's cheaper than good electrical solder.

 What I
>was told to watch out for in silver solder is that it is indeed commonly
>used for mechanical instead of electrical work so much of it is acid core.

   You have to watch out for any solder and make sure it's for electrical
work. There are many other kinds of solder and many (most?) of them have
acid fluxs. You can use it on electrical stuff but you'll be replacing
everything in about six months!
>
>Perhaps it was this list, but I have just read about solder removal alloy.
>Its a solder looking stuff used to remove complex multipin chips. You melt
>it onto the existing solder and it forms an alloy with a VERY low melting
>point so the chip can be removed with much less heat, ie wave a heat gun
>and it drops off.

  That's an interesting idea. But I certain that you'd have to heat the
joint to the melting pont of the old solder before this stuff would alloy
with it. If that's the case then you could just take the part off then and
not go through all the rest of the procedure. I've mixed various lead
alloys for casting bullets and you have to heat the mix to the melting
point of the element with the highest melting point before they will all
melt and alloy together. This is true even if the alloy has a lower MP than
the individual elements.


   Joe
Received on Fri Dec 03 1999 - 20:19:10 GMT