[remove soldered chips] Cheap & Dirty

[The Dark force of dance]

Y-ellow Quinton.

At 08:30 AM 05/23/99 CDT, Quinton Fulsom wrote:
>A buddy of mine at a reclamation/surplus store grinned & took me in the back
>room when I asked him about this.  I had dozens of boards to rework and
>wanting to save the hard to find ICs had inquired about wave soldering.  He
>showed me this method which will not damage the IC's etc.
>He uses an electric skillet filled about 1/2 inch with the type of fine sand
>like in ash trays.  It sits for about 1/2=1 minutes and then you pick it up
>turn it over and they literally all just fall off the board with a couple of
>shakes.  About $10 bucks and your set!  Coolest thing I'd ever been shown
>probably

This sounds like a very interesting process. What concerns me however is
that if it takes a minute or two to heat up, the yield rate would surely be
pretty poor. Most chips are rated at 10 seconds per pin @ 300 - 350
degrees. Solder melting point. So if you were heating the boards up for a
minute or even half a minute, surely the chips would become heat-stressed? 

The other thing that crossed my mind is that this would not work for all
PCBs. If a PCB has been made properly, the pins are at least flayed out so
that they make contact with the doughnuts or plate throughs directly. The
solder, in effect is only a glue that holds them in place. Therefore just
bashing a well made board won't force the chip to just, drop out. You have
to pull them.

Having said that, I'm intrigued with the process. If one could pull the
chips without heat-stressing them too much this could be a most interesting
technique. Thanks for sharing that.

Be absolutely Icebox.

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