How I Desolder

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I just realized tonight as I sat down to solder some more of my cat feeder motor driver together that half of my diodes were soldered into the board backwards. I had to figure out a way to remove them or scrap the motor driver I had already soldered to the board. Luckly, I managed to remove the diodes and solder new ones in.

How I desolder two point components:

WEAR SAFETY GLASSES

Sure, I make look silly at my bench with my safety glasses over my seeing glasses, but I would rather not flick any hot solder in my eye. No sir! I wear my safety glasses every time I solder.

1. Clear the pad with a desoldering wick

My method involves heating the solder and pulling the part, but first I try to remove as much solder as I can using a desoldering wick. It’s a¬†finely braided copper coil that will suck up the solder I want to remove. I place the wick on the soldered pad and then the soldering tip on the backside of the wick. I rock the tip back and forth a little to work the heat against the braid, which may not actually be doing anything but seemed to speed up the process.

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2. Perform a heated half pull

After I pull the wick away, the pad is clear of most of the solder, but the component is still stuck. Since the diodes I need to remove are very small and all set against each other, its extremely hard to grab them with any kind of pliers.

Instead, I use an old resistor (preferably one I have an abundance of) and loop one of the wire leads under the diode lead I want to pull. Using needle nose pliers, I grab the looped lead of the resistor and with my other hand, I heat the pad with the soldering iron. When I melt the residual solder, I pull on the component and one side pops out.

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3. Perform a heated full pull

Now, grabbing the hanging component is easier to do with the pliers, so go ahead and grab that and heat the second pad with the soldering iron. The part should be able to be pulled free. Make sure not to send the PCB board flying when you are yanking things around. Hot solder burns!

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4. Clean up

If there is still some messy bits of solder on the pads, try to clean these up with the wick. My wick left some residue on the board. If I wasn’t so lazy, I would give this a quick rinse with 70%+ isopropyl alcohol to prevent me from contaminating the joints of the new diodes I have to put in.

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That’s it! Quick and simple, and you should be back on track in no time.

How do you desolder?

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