Electronic – Question about soldering/desoldering

soldering

I've just bought new 30W soldering iron and now that I'm home, I've tried to desolder few capacitors from my MBO. Anyway, I've turned the soldering iron on, waited few minutes for it to heat up and then put the tip to the part I wanted to desolder. I was amazed – nothing happened !! Well, after let's say 30 seconds (I know, that's too long but I didn't get anything e.g. smoke or something and the capacitor didn't heat up because I was holding it on the other side) I've managed to somehow desolder it … But now I have solder in holes, and I thought well, that's no problem.

I've used this technique:
Pic

but unfortunately, this doesn't work. I can't melt remaining solder (in the holes) by applying tip of soldering iron to the one leg of capacitor. Actually, I don't think that I can do anything with this soldering iron …

Is there something wrong with it or with how I am using it ?

Thanks !

Best Answer

First of all: modern PCBs use lead-free solder. It has a higher melting point and a different "look" when solid. Sometimes it helps to apply a little bit of lead solder to get a better heat transfer between the soldering iron and the solder joint. After the whole soldering joint is molten, I use a vacuum plunger ("solder sucker") to remove bigger amounts of solder. Remove the soldering iron to avoid overheating the component.

Then (the component wire is still in the hole) I use some quality brand desoldering wick: I place the desoldering wick in such a way that it has a good contact to the solder joint, and then press on top of the wick. This way the wick has a good contact to the solder joint.

About heating up the capacitor: It may well be that you overheated the cap, I'm not sure if the metal case is has a good thermal coupling to the contacts.