Hints for desoldering

First of all, know what your goal is. Is your goal to remove an unwanted chip from an important board, or to remove an important chip from an unwanted board?

If it's the former, the best way is to cut off all the legs of the chip, then desolder each pin individually. The pins can then be removed with a soldering iron and a pair of pilers. Cleaning out the holes with a desoldering iron is rather simple at that point.

But if it's the chip you want, here's some tips for desoldering DIP package integrated circuits:

• I use a Radio Shack desoldering iron. This has a red rubber bulb on it and a hollow tip. It's cheap and works well.
• Use a fresh tip for important projects! It's not worth trying to save two bucks only to ruin a circuit board or a chip.
• New tips must be tinned! If not tinned, their lifetime is only a few hours.
• Practice, pratice, practice! It will help to practice on a junk board rather than messing up on your first attempt with an important chip.
• The higher-tech the board you are desoldering from, the more difficult it will be. Old-fashioned one- and two-layer boards are the easiest. Newer boards tend to have smaller holes which make suction much more difficult.
• Wait for the joint to completely melt before sucking out the solder. If you suck too soon, you may not be able to melt the joint properly any more. Wait about four seconds, or five for the four "corner" pins.
• When you have sucked out the solder from all of the holes, push all the pins to "crack" them off of the remaining solder in the hole.
• If you have done everything right, and it's a one- or two-layer board, the chip should practically fall out of the board. If not, you need to very carefully pry the chip up, just a little at a time from each end. Watch for pins that are clearly stuck. You may need to use a soldering iron to heat the pin while pulling.
• Any pins which have lost their bottom half need to be repaired. Simply get a new pin from a donor IC, and solder it onto the stump.