A De-Soldering Primer
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By Wayne Burdick, N6KR
(republished with the author's permission) Removing resistors and other parts from double-sided boards is easy and fun. After years of careful analysis of my own technique I have documented the process. I start with technique #1, below; if that doesn't work, I try #2, etc. Good luck! 1. Turn the board over. With one hand behind your back, a wry smile, and the confidence of a pet surgeon, simply heat the lead in question and listen for the pleasant sound of the component hitting the work bench. 2. Well, that *would* be too easy, wouldn't it. Staying with the solder side for now, locate a large solder sucker (the larger the better; it should frighten smaller pets when brandished). Heat each joint and deftly suck out the solder with a single satisfying Thwop! Listen for the part hitting the bench. 3. Didn't fall out, eh? No problem: rummage in that tool bin for a shiny new roll of solder wick. Crack open a beer, too, and take a generous swig. Wedge that wick in between the lead and pad, heat until you see the solder flow nicely onto the wick, and pull it out of the way just in time to see a beatiful, black annular ring around your component lead. Nudge each lead with your iron and keep your fingers crossed. 4. OK, so you've got a tough customer: small lead, hole just barely larger, and a bit of off-color solder that can't be bothered with any of the usual techniques. Have another sip of that brew. Vigorously flip the board back to the component side. Now grip the lead professionally with your most elegant long-nose pliers and hold on tight. Give it a playful yank, then pray. Should pop right out. 5. Damn. Finish the beer and get out your brutal, 8" electrician's long-nose. Grab the component with gusto this time, buster, then tip the board up at a 45. Turn up your soldering station to max and heat that baby up on the backside. Pull down hard with the pliers. 6. No go? Hmmmm -- let's get serious. Put the board up directly on its edge and hold it in place vertically with your chin. Since your iron is suspect by this time, test it for several seconds on the nearest exposed skin. (Doing it by accident is just as effective.) Heat the joint with *feeling* this time. Lunge and parry. Don't worry about the pad, traces, or other parts--this is war! With maximal chin pressure exerted to hold the offending board in place, pull the lead out, out, Out! 7. OK, so you "...couldn't get hold of it...," blah blah blah. Fool! You must risk everthing at this stage. Insert a small screwdriver under the part, and white-knuckle that soldering iron on the obverse. Pry and heat until it pops. (Note: It is important to keep in mind the concept of "kick-back" should you succeed at this. PC boards are likely to wobble, flop, slip, then fling out of your grasp once the offending little monster finally lets go, taking test leads and soldering station with it.) 8. So, what kind of inept dweeb are you, anyway? Give up! Clip the part. Leave some lead to grab onto and repeat #6 and 7. If your face has turned red it is best to shield the work from veiw with your body, then steal a quick look behind you to be sure noone is suppressing a giggle as they watch this humiliating display. 9A. The lead came out but you STILL have some solder left in the hole? Gads. Find another part that you can sacrifice. Press its helpless lead into the depressingly small pit you made in the center of the pad. Heat the base of the lead until you achieve Punch-Through. Yank and Heat, Yank and Heat. Evetually the solder will give up in disgust and the sacrificial component lead will slide smoothly, signalling victory. 9B. To your left is a hand drill; to your right is a #60 bit. You know what you must do. 10. Now—you brute!— now that you've overheated the pad, broken the trace, cracked the component, gouged the board, pitted the tip, blistered the skin, wasted a beer, and irrefutably proven once and for all that you should have taken up gardening instead, NOW maybe you'll learn the color code! |
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