Soldering Components and PCBs

"Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal (solder) into the joint, the filler metal having a lower melting point than the workpiece. Soldering differs from welding in that soldering does not involve melting the work pieces." ^

William K. Borsum Says:

[Use] a GOOD, HOT soldering iron with a small--but not too small--"angled screwdriver" style tip. I used Edsyn's 951SX (1/2 price sale at radioshack.com $75 as of 99/09/10) with the 95 watt heater and tips--and keep it turned all the way up.

Once upon a time I watched two professional painters do the door and window trim in our lab facility. They used EIGHT INCH WIDE BRUSHES, about two inches thick! NO JOKE! They had learned to feather the edges in holding the brushes and could go to a hair fine edge. And back to the paint bucket every other window. Try that with your tiny little brush.

The moral: In soldering the object is to get HEAT into the joint as rapidly as possible to melt and flow the solder completely--then get OFF. Thus minimizing total heat flow into the part itself. You can't do this with a teeny-tiny tip--or with a tip that is just over the melting point of the solder.

I use what are commonly called bent chisel or bent screw-driver points about 60 mils wide with a 90 watt temperature controlled (But set all the way up) iron designed for maximum heat transfer to the tip. Iron or gold plated so you never need to file them or do any major cleaning, and they don't contribute base metal to the solder.

Turn the tip sideways and its only 10-20 mils thick for those narrow pads, flat on for the bigger header pins, and with the long bent edge across multiple pins. All in one.

Apply the heat (tip of the iron or hot air pen) to the largest, most thermally massive part first, with just a touch of solder on the iron after applying a bit of flux to the joint. If the parts are more or less the same size, try to touch both at once. Quickly apply solder to the parts (not to the iron), ensure the solder has fully melted and flowed into the joint, then get the iron off and let the parts cool.

Never hold the iron on the parts for more than a few seconds at a time. If the solder isn't melting when you touch it to the parts after a second, back off, clean your iron, get a bit of solder on it, add a little flux to the parts, and try again.

When soldering rows of pins, especially on a sensitive IC or easily melted header, dont proceed in order; instead jump around on the pins to avoid over heating any one part.

Also:

• Surface Mount Soldering
• Solder Flux
• Soldering with a Solder Pot
• Solder Resist
• Air Wiring
• "Manhattan" style construction
• Holes

  .