Soldering - Let's talk.

[Armagedda]

Ok, so I'm in the process of switching over the red switches in my YOTD to greens and I'm getting stuck in the sense that I can't get all the solder out of the solder points. I'm not sure if it's my lack of skill or perhaps my solder sucker is bad. I'm having an especially tough time with the led solder points. I'm going to hunt down my finer iron tip as I'm a little too scared to leave the iron on there for too long. 15 - 20 seconds at 350 - 400C. Do you guys think I'd be having more luck with some copper braid as opposed to the solder sucker or can you see where I'm going wrong at all from anything I've written here.

Also, copper braid vs. vacuum pump in general, what do you guys think?

[harrison]

i've found braid to work so much better for desoldering LEDs and switches alike.  i re-and-re'd two switches on my ducky today.

[Magnusian]

Depending on your iron, skill level, etc, you may not be able to remove all of the solder at once. In those instances melt the solder and remove say the LEDs one post at a time while the solder is still molten.

The best thing to do is practice if this is your first time doing anything important, if you are worried about wrecking the board, find some old eletronic piece of trash and desolder it as practice. Since it doesn't matter if you wreck it or not, get a feel for how you need to do things with your particular iron. It's a bonus if the thing you take apart has SMD components because you can also practice putting them back on.

Personally I prefer the sucker to the braid. I typically use a medium-sized tip for just about everything.

[Loligagger]

One of these would probably make your life easier.

[TheProfosist]

I like my soldapult does the job everytime.

[Armagedda]

Depending on your iron, skill level, etc, you may not be able to remove all of the solder at once. In those instances melt the solder and remove say the LEDs one post at a time while the solder is still molten.

The best thing to do is practice if this is your first time doing anything important, if you are worried about wrecking the board, find some old eletronic piece of trash and desolder it as practice. Since it doesn't matter if you wreck it or not, get a feel for how you need to do things with your particular iron. It's a bonus if the thing you take apart has SMD components because you can also practice putting them back on.

Personally I prefer the sucker to the braid. I typically use a medium-sized tip for just about everything.

Naturally, I expected this and I can get most if not all the solder out from around the switch pins in a few attempts. I'm not expecting to get it all out in one go. But I guess my real obstacle is that I can't seem to make the solder on the led pins melt or if it is I'm not quick enough with the sucker. This is why I'm asking about the braid as I'm expecting this to be user error rather than faulty equipment. It may be that I'm just moving the iron away too quickly.

One of these would probably make your life easier.

I'd rather not spend the money on another iron until I know that I'm using my sucker incorrectly. Braid's pretty cheap, yeah? I figure I'll grab some of that and maybe keep trying in the mean time.

How sensitive to heat are the pcb in boards? How long would you more seasoned solderers be comfortable putting the heat to a point of solder without fear of damaging the board? Again, I'm working with my iron set between 350 and 400 C.

[Tranquilite]

The thing with PCBs with traces on both sides of the board is that it is sometimes hard to get the solder removed from both sides. If you cant get the solder completely removed, then it would be a good idea to change strategies and merely remove the LED while the solder is still molten.

To do this, just get a pair of fine tweezers or something similar and pry it under the LED on the other side of the board and put just a little prying force on it, then melt the solder joints with your iron one quickly after another (add more solder if you have to). Once both joints are molten at the same time the LED will just pop out.

I was once dumb enough to do an entire switch swap of a backlit board myself, and I had to use this method on a number of the more stubborn LEDs. It may have been a better idea to do a switch swap on a non-backlit board before jumping into this project

As for copper braid vs vacuum pump, I've always been a fan of the pump myself, and have never had much luck with copper braid.

Well, either way, good luck with your project!

[Armagedda]

Alrighty, I'll give the tweezers idea a go, sounds like it might be a good idea. And like you I'm regretting setting my eyes on a backlit keyboard for this project. I might even end up buying a non backlit MX black board for this project instead as I've not tried blacks and this is looking to be a very painful process.

[TheProfosist]

I think id recommend higher temps but i dont know the temp i use off hand on my iron.

[Armagedda]

I think id recommend higher temps but i dont know the temp i use off hand on my iron.

This is exactly the kind of info I'm after. What's the upper limit on the amount of heat I can apply without fear of damaging the board? My iron only goes up to 450C and like I said I've been operating between 350 and 400C with more success apparent towards the 400 mark. I'm just not sure if it's "safe" to push it any higher.

[WhiteFireDragon]

I think id recommend higher temps but i dont know the temp i use off hand on my iron.

This is exactly the kind of info I'm after. What's the upper limit on the amount of heat I can apply without fear of damaging the board? My iron only goes up to 450C and like I said I've been operating between 350 and 400C with more success apparent towards the 400 mark. I'm just not sure if it's "safe" to push it any higher.

lol are you kidding me? Standard leaded solder melts at ~180C, but since almost everything is RoHS nowadays, the Ducky has lead-free solder which melts around 220C (depending on composition). When the solder melts, you should be able to suck up the solder. Leaving on the iron longer adds unnecessary heat. 15-20sec is way too long.

What iron and solder sucker are you using? It's a misconception to only look at temperature and ask what you should set your temps at. Everything is in terms of heat transfer, so have a larger reservoir of heat and how fast your iron can recover (this is why higher wattage irons are better) plays a much bigger role than the temperature dial. This is why there are different levels of equipment quality, and it sounds to me like you're using cheap equipment, or either have a low heat capacity tip or low wattage iron.

If those temp readings are even a bit accurate, then you would have fried your board long ago. Keeping the iron on there for 20 sec is just ridiculous lol

[danielh]

Try some braid!

[jwimsett]

Are you using flux?

[rknize]

Lead free solder doesn't flow as well as the good stuff and it also oxidizes quickly while heated.  If you don't get it out on the first attempt, you will be even less likely on each subsequent attempt.  The best thing is to reflow the joint with good old 44 rosin core solder and try again.  The fresh solder will pull the old solder out.

If you are using a separate solder sucker, don't be afraid to get it right on top of the iron tip and pull the iron out as you press the trigger.  As long as it has a Teflon tip, it will resist melting as long as the contact time is short.

[__red__]

My advice is this.

When you start a de-soldering process, you have a decision to make and you need to make it before you even expose the board.  That is, what is more important to you, the PCB or the components?  Your answer to that question will determine which method you should use.

[Magnusian]

If you are using a separate solder sucker, don't be afraid to get it right on top of the iron tip and pull the iron out as you press the trigger.  As long as it has a Teflon tip, it will resist melting as long as the contact time is short.

This. Many suckers even come with spare tips incase you melt one beyond the point of usefulness. Don't be afraid to get it right in there.

[Leslieann]

If you don't get all of the solder, try adding some fresh. Board makers use a different blend solder that doesn't melt as easy. Adding some, can lower the melting temp and allow it to flow better.

Cheap suckers may not do a lot of sucking. Check yours, a bit of grease, vasaline, etc...  Anything to help it seal can help.

Another thing is that temp is over-rated miss-understood.
I have found that the thin, pointed irons have a serious flaw in them in that once you touch it to something, you can suck the heat right out of it. The tip simply cannot hold enough heat in it. Your goal is to get the solder hot, before the heat can spread. Thinner tips have a hard time with this, and leave you stuck trying over and over again to get the solder to melt, this means more and more heat flowing into the joint, and spreading, and in some cases causing damage.

My best iron has a thick copper tip I ground into a blade. Get it hot enough and there is no way a solder joint can suck out the heat. It works EVERY time and it's only a 35 watt iron. Meanwhile I have seen pointed 65 watt irons struggle with joints this does at a touch. My fancy variable temp 55watter (albeit cheap) burned out a mouse I was working on, something my 35 watt has never done to me and trust me, I did things with it you wouldn't dream of. Yes, I'm sure a high end, variable temp pointy iron like a Race Station or something would probably do better than my cheapie, but I find it odd that a $20 Weller iron from Radio Shack serves me better than almost anything I can buy for less than $100. I have yet to find something it can't handle.

[TheProfosist]

I normally use 600 F (just over 300 C) for general stuff for lead solder. But for no lead solder I have to raise the temp up a bit. I havnt done it in a while so i dont remember off hand how much higher i go but it really inst too much. And yes 20sec is way too long to be on a joint. As for a solder sucker I recommended a Soldapult they work wonders and are leagues better than the cheap ones that try to knock them off.

[kbfreak]

What do you think I should use to remove a defective mini USB port on the PCB (and eventually replace it)? These have such tiny solder points and my bulky sucker really don't seem to suck up the solder of this size well either. Any suggestions?

[Magnusian]

Hit the contact points with the iron while grasping the component with some needle-nose pliers, when they're melted, yank.

You could try bridging several of them at once with fresh solder and seeing if the sucker does a better job, just keep in mind if you do this, you'll have to make sure the contacts on the board are not bridged after the fact.

[takaki]

pictures guys pictures.

say you could show us how you position your soldersucker when you are heating it up with your soldering iron would really make a lot of difference.
*safety, a photo showing how you should position your sucker doesn't return you to turn the soldering iron on, you may even use a pen to show how*

[TheProfosist]

pictures guys pictures.

say you could show us how you position your soldersucker when you are heating it up with your soldering iron would really make a lot of difference.
*safety, a photo showing how you should position your sucker doesn't return you to turn the soldering iron on, you may even use a pen to show how*

i just poke it with the soldering iron then put my soldapult ove the joint and push the button.

[geekabit]

What do you think I should use to remove a defective mini USB port on the PCB (and eventually replace it)? These have such tiny solder points and my bulky sucker really don't seem to suck up the solder of this size well either. Any suggestions?

There are several options. My personal favourite is the first one, but ymmv.

First desolder the metal shell. Heat up one side, add a little solder if it doesn't melt. Use the sucker to suck up most of the solder, then lift the pin off the pcb with a small screwdriver or tweezers. Repeat for the other side of the metal shell. Take care not to lift the connector up to high and damage the pcb on the pin-side. With the shell desoldered, only the 5 data pins are left. Add more solder to the pins, so there is one big blob covering all the pins. Lift the connector off the board using tweezers. Then use the sucker to remove the blob. If there is some solder left, use wick/braid to clean it up.

Another option would be to cut up the connector. Carefully cut the pins with a small knife. Be careful to not cut or stress the pcb. Then heat up the pins one by one and remove it with tweezers. This works for most multi-pin parts.

With the old connector removed, you need to mount the new connector. Fix it in place by soldering one or two pins. These solder joints don't have to be perfect, they just need to hold the connector in place while soldering the other pins. With the connector fixed in place, you can solder the remaining pins. Then re-solder the pins used for fixing and the metal shell. You might want to press the metal shell on the pcb when the solder hardens with a small screwdriver.

And some general (de)soldering tips:

My solder sucker works best when cleaned and oiled. This makes a night-and-day difference.

You transfer more heat from your iron to the pcb when there is more contact surface. A screwdriver or chisel shaped tip works better than a conical shaped tip. Also you could try to add some solder when (old) solder doesn't melt.

Soldering tiny pins (like micro-usb) is easiest with a small soldering tip and thin (0.5mm or so) solder.

[bpiphany]

Flux, and thin solder, and flux. With that it doesn't really matter if the iron is a bit large. A chisel shaped tip really helps though, they even have sharp corners if you want to have a tiny contact surface. And did I mention flux? Drench the thing in flux and heat it up. If there isn't huge amounts of extra solder it usually flows to where it should be.

[hasu]

What do you think I should use to remove a defective mini USB port on the PCB (and eventually replace it)? These have such tiny solder points and my bulky sucker really don't seem to suck up the solder of this size well either. Any suggestions?

I assume it is SMD. This worked well for desoldering TQFP chip without damage of PCB trace, it'll also work on USB receptacle.
https://www.sparkfun.com/products/10925

[kbfreak]

Thanks guys. It's amazing all the great tips we can gather at a forum like this. Sounds like I will need to buy some flux and a more precise and stronger solder sucker before I try anything!

[engicoder]

]i just poke it with the soldering iron then put my soldapult ove the joint and push the button.

+1 for soldapult

If you have alot of cash...try the Hakko 808