Instructables

How to Desolder Large Difficult Components

Hey folks,

This is a mini-instructable on a method of de-soldering that makes it easy to remove large, delicate or otherwise difficult components without damaging them, as long as you don't mind destroying the PCB in the process.  This makes parts harvesting from old electronics much easier and with a greater success rate.

This method is useful when the object you are trying to desolder has a lot of pins, especially with a through-hole-plated PCB which can be notoriously difficult to suck the solder out of using a pump or braid. Heat guns aren't always an option either if the part is made of plastic.  In my case, these ZIF sockets have the metal pins going right into the plastic body, and applying heat for more than a few seconds will melt the body of the socket and ruin these very expensive items.

Tools required are: 
  • Soldering iron
  • Hacksaw
  • Vise
  • Pliers

 
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Step 1: Saw Through The PCB

Put the PCB in a vise or hold it down to a table.  Use the hacksaw to cut into the board and separate the component you want from the rest of the board.  The fiberglass should be quick work with a standard metal-cutting blade.

Place the board in the vise as firmly as possible to allow you to use the saw to cut through the bottom of the PCB and separate the pins into groups, as shown in the picture below. Keep the blade level and go slowly so you only cut the PCB and not the component itself.  This will allow de-soldering the pins in small groups of two or three pins.  Cut gently and try to feel when the saw falls through the board so you don't cut into your component.


floxin1 year ago
Years ago I watched an old pro working with the method suggested by Kittypuss. The only difference was that he heated the solder till it was runny and then gave the whole board a vigourous shake, like when you shake a medical thermometer to lower the mercury before using it. He kept the soldering iron on the spot while shaking the board. Practice a few times and you get the right movement coordination. The only drawback will be some solder splatters on the floor but they are very easy to remove scratching with your fingernails. I learned the trick and keep doing it successfuly.
Very useful technique.

De-soldering braid for quickly "soaking away" hot solder from component pins, can be substituted with a piece of fine multi-stranded wire.
Braid gives better performance with a little flux applied to it first.
mattthegamer463 (author)  ElectroFrank1 year ago
Agreed. Most solder braid appears to come with some sort of coating pre-applied. It often leaves a gooey brown mess when you are done.
Kittypuss1 year ago
If the pins have enough clearance ie the pins are a loose fit then you can simply apply a very hot iron to one pin at a time and as soon as that pins solder is molten smack the board on a hard surface solder side down. All the solder will squirt out leaving the pin free. Repeat on all pins and then jimmy the part free with a penknife blade. Most de-soldering suction irons should work if you first add more solder to the joint before sucking it out. Doing this somehow gives more impetus to the solder which then flows out easily. Question: What do you do with the buckets of loose parts which accumulate very quickly. Rather do as I do and just leave the complete PCB's in your ceiling until you need a component. They are very much easier to locate that way and are out of your way.
mattthegamer463 (author)  Kittypuss1 year ago
Since the unnecessary PCBs are out of the way, the components can be easily organized into containers. Also, I only collect expensive or difficult to find components and leave behind resistors, small caps, etc. Since they are cheap and once you have a good selection you don't need to amass a high quantity, so that keeps the clutter down.
Keeping the clutter down for the misses, good plan.