Homebrew PCBs

In a message dated 8/29/2003 8:14:12 AM Central Standard Time, 
MUMIN55555@HOTMAIL.COM writes:

> i read your answers, thanks a lot. but here, in israel there are 
> almost no electronics stors, and the ones existing, do not have  a 
> lot of stuff. so what is flux? is "electronics 
> solder" is the same as "solder paste" that i can get here?
> 

Surely in Israel, "electronic solder" is readily available if you know how to 
FIND it!  That little country is "High Tech"!   
"Flux" is the substance that makes solder "take" well.  In "electronic 
solder" it is usually a "core" in the solder-wire itself, and is usually a 
rosin-based gooey light-brown stuff that is non-corrosive when room-temperature.  BUT, 
it becomes mildly acidic when heated, and makes the solder flow nicely on 
bright terminals.

"Solder paste" is a dark brown CORROSIVE substance one might use for, say, 
roofing or plumbing with copper pipes.  It should ALWAYS be wiped off with soap 
and water after soldering is done.   Else, its residue will CORRODE the 
base-metal and at least make things UGLY.   It has the consistency of "axle grease" 
at room-temperature (20-21° C). 

"Solder paste" should NOT be used for electrical stuff unless that is the 
ONLY way you can make a particular soldering-job work, and in THAT case, it must 
be washed off CAREFULLY, immediately after use.

The "acid" in "acid-core" solder is the flux for that kind of solder.  It is 
very corrosive, and should be used ONLY for very difficult metals to solder, 
and VERY CAREFULLY washed off after cooling!

Lotsa luck!    Jan Rowland


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