More Soldering basics

[Zthun]

Hi everyone,

I've been reading more into doing basic soldering (been doing other stuff), and while I'm really good at getting things to de-solder using a desoldering pump (not very good with the wick, problem described below), I'm having a problem getting my solder to melt.

The only way I can get my solder (rosin-core flux 60-40), to melt is to touch the actual iron instead of the metal on the board. I have to roll the solder off of the iron and onto the board instead of putting it on the board itself.

I've noticed the same problem with the wick. I can't get the wick hot enough to cause the solder to melt unless I put a real heavy amount of pressure onto the back side of the wick, which actually has caused the wick to be attached to the board itself.

Normally, I believe the technique is to touch the soldering iron to the metal on the chip, and then place the solder onto the hot metal, thus melting it onto the board. Again, apparently my soldering iron isn't getting the metal hot enough. Am I doing something wrong, or is this a problem with the iron (I have a 25 watt iron)? Any help is appreciated.

[jonjandran]

40 watt iron. :)

[shadows]

25 watt should be enough.
When you use the wick, first touch the solder on the board for 1-2 seconds so that it starts to melt, then put the braid on the solder and the iron tip on top of the braid.
Also make sure that the tip of the iron is clean and tinned. It should look shiny, otherwise it doesn't work well if at all.

[channelmaniac]

The iron should have a nice coating of solder for the solder to melt to. If it doesn't, it'll have an oxide layer on the surface which will make it harder for heat to transfer into the joint to melt the solder that you are trying to add.

RJ

[jb143]

Desoldering wick is a pain to use. In general though, the secret to desoldering is counter-intuitive. To remove solder, add more solder. Especially of a tough joint that just doesn't want to let up that last little bit of solder.

[Zthun]

25 watt should be enough.
When you use the wick, first touch the solder on the board for 1-2 seconds so that it starts to melt, then put the braid on the solder and the iron tip on top of the braid.
Also make sure that the tip of the iron is clean and tinned. It should look shiny, otherwise it doesn't work well if at all.

This is actually something that has been bugging me about this for awhile now. When I try to tin my tip, the solder just balls up and falls off the side. None of the solder stays on the tip. I think this is my main problem. Since I've been unsuccessful at tinning the tip of the iron, all I've done is oxidize the tip. After applying solder (and having it run off), when I clean the tip on my sponge, it appears black instead of silver. At first, I tried it this way, and it appeared to work, but the only way I've been able to get the solder to heat up is to run it off the tip and onto the board. I'm using 1mm solder which I think is too thick. Do I have to apply liquid flux to the tip first? I thought that the solder I bought was a rosin flux solder (in the core), but maybe I misread something.

[shadows]

Yea if the tip is black, then its oxidized and pretty much useless. I did the same mistake when I started soldering, the tip became black.
You either can try to clean it up.
I used flux, the sponge and a whole bunch of solder to get it back in good shape. But that's going to take you a long time. Took me over an hour, waste of time, but the store is just to far away from where I live.
I think some people use fine sandpaper or a knife to scrap the black stuff off, but that could damage the tip.
Your best bet is just to get a new tip, most decent soldering irons have replaceable tips. Should cost you about 4-6$.
Make sure to tin it before you start soldering and tin it again once youre done to keep it clean.
You can apply extra flux to the board, it will clean the contacts better. But it's not necessary.

[Logicdustbin]

buy one of these, you will be glad that you did:

http://www.dealextreme.com/details.dx/sku.6380

as for solder wick, try dipping the end in soldering paste, then place it on the solder to be removed and place the well heated iron on top of that.

its like anything else, you just need to practice.


/was never able to get used to the de-soldering suction pump thingy

[Mnemonic]

Yeah, I remember the first soldering iron tip I ever used... didn't take care of it... ended up like yours (black and useless). Don't feel bad though, lots of people make that mistake when they're starting out. It's just one of those things that experience teaches you. Practice makes perfect, and all that. Consider it a rite of passage. :)

I find that when heating up the contact points, it sometimes helps to apply a tiny amount of solder between the iron and the contact... not enough solder to actually start soldering the connection, or even at the connection point... just enough to help the heat transfer from the iron to the metal.

As for removal, I too have had little luck with desoldering braid. Perhaps I need a higher wattage iron to use it well (I use a 30W), or perhaps the weave/size of the braid plays a significant factor. But, to be honest, I've come to prefer a solder-sucker (or pump, or bulb, or whatever you wish to call it) over the years. I also agree with jb143: Sometimes you just have to add a tiny bit of solder to get the rest off, as strange as that sounds.