Removing Solder... Wilkey, where are you???

Is removing solder as easy as it sounds. Added solder drops to CBP 1650's last spring thinking of removing solder drops. Could I just take an iron, reheat and rub the top of the cells into a wet sponge to remove molten solder?

Thanks,
Dave

Use some solder wick. Does the job nicely.pic

The wick will suck up solder when heated and pressed against the area you want to de-solder.

Another vote for desoldering wick. I've given up on the spring-loaded solder suckers (they've lifted too many traces right off the board) and I can't justify spending the $$$ for a professional desoldering station.

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nekomane said:
Use some solder wick. Does the job nicely.pic

The wick will suck up solder when heated and pressed against the area you want to de-solder.

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Where can you buy this solder wick at? I don't recall ever seeing any while out looking for soldering supplies.

Thanks,
Dave

Solder wick is available at radio shack and electronic part stores.

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Lynx_Arc said:
Solder wick is available at radio shack and electronic part stores.

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Thanks...

Roger that. Solder wick is a good way to get the solder off of a part you want clean. Solder wick is just braided metal wire that has some sort of flux on it, I think.

Some of it is pretty narrow. If I have to do a wide blob, I just fold the wick over, next to itself so it covers a broader area. Just remember to get keep your iron near the pickup point or your wick will freeze right up in the cooling solder. In other words, heat-wick-remove immediately.

Dave, you have to come back and let us know how you did. Did you get to practice on some dead alkies?

Are you using a good flux? I use Sears Craftsman liquid electrical grade rosin flux. Very effective and easy to apply.

Wilkey

How about using solder with flux in it. Is this easier to use in battery pack installations?

Bill

Another vote for Solder wick, I use it frequently on projects and it can be had in varying widths.

Ryan

Hi, I hope you don't mind me dropping my coupla cents into the molten flux?? /ubbthreads/images/graemlins/grin.gif

...just be sure to remember not to hold the bare wick while applying heat to it... ouchies!!! (I have melted the plastic wick-holder the wick comes in many times.) hehehe

Another thing, if you have just finished using the solder wick, it will more than likely leave a lot of gunk (flux and general rubbish) on the place it was used. If this is a battery terminal or similar place used to conduct electricity, give it a good wipe over with either metho or acetone of some sort. There is a propper pcb cleaning solvent available, I use this with an old toothbrush when cleaning my pcb's.

If you can't get the wick, you can heat the area and give the piece a quick flick and most of the excess solder will fly off.

Sometimes, you will also need to apply more solder initially just to get the flux going and the heat transferred so that it can be more easily removed.

GOOD LUCK!!!

Tim.

A couple of methods I've used over the years when doing repairs and making my own projects:

1) A good quality (i.e. aluminum body) solder sucker. Just remember to clean it fairly often. Great for cleaning out holes after you've removed a part.

2) Solder wick. This sees very occasional use when nothing else works (i.e. removing solder bridges between pins of a surface mount IC). You can make you own by stripping the ends of any stranded wire and dipping it in soldering flux. Not as fancy, but works just as well.

3) Heat the solder you want to remove to until it melts, and then immediately give the item you're removing it from a light tap on the table (or in some cases a slightly harder tap). I've used this method also for cleaning out holes in circuit boards. Noisy but effective.

4) Desoldering through-hole (DIP) ICs-cut all the pins off the main body of the chip with a small cutting pliers. Remove the chip. Take the pins out of the holes one by one by heating each pin in turn, and yanking it out with a tweezer. When you're done clean the solder out of the holes with a solder sucker, clean the board with alcohol, and solder in the new IC. I've replaced 40-pin chips in under 3 minutes using this method.

5) Removing surface mount ICs-apply a liberal blob of solder to both sides of the chip, bridging all the pins. Jump the soldering iron back and forth between the two sides. The goal is to have the solder blobs on both sides molten at the same time. When this happens, quickly grab the IC with a tweezer and yank it away from the board. If all the solder is molten it should come right off. Clean all the excess solder from the pads using a solder sucker or solder wick. Install the new IC, being careful not to bridge the pins. If you do bridge the pins, clean it with solder wick. This method works great on most surface mount ICs up to maybe 20 pins. After that they're simply too large to keep the solder blobs molten on both sides for yanking off. You need special SMD desoldering equipment. You might need a magnifier to see what you're doing. I can solder 50 pin per inch SMD ICs with my naked eye, but that's just me. I know people who have trouble with DIP chips without a magnifier. Oh, and lay off the coffee for 24 hours if you'll be doing this. Hand tremors can cause havoc when dealing with stuff this small.

6) Removing most two or three leg components-heat both pads simultaneously, yank component out, clean holes, put in new component. Similar to (5) except fewer pins.

You can just cut the solder off the top of cells with a new, sharp blade. It's pretty soft. Grinding, scraping or filing also works.

I have found laying a resistor leg or similar across multiple pins is a great way to get multiple pins heated up to reduce the chance of lifting pads/track...especially whilst 'yanking them out' hey jtr 1962? /ubbthreads/images/graemlins/wink.gif

*Raises hand* GUILTY!!

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Ginseng said:

Some of it is pretty narrow. If I have to do a wide blob, I just fold the wick over, next to itself so it covers a broader area. Just remember to get keep your iron near the pickup point or your wick will freeze right up in the cooling solder. In other words, heat-wick-remove immediately.



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Actually, you'll probably have better luck with pushing the mesh backwards onto itself. It will splay out to several times it's width and thus have lots of openings to 'soak up' the solder. Far better results.

And you should put the wick on top of the joint, and the iron *on top* of the wick. Like all good soldering practice, heat *the work* (in this case the wick) to temperature and let it melt the solder. As soon as the joint collapses down (melts), pull both the wick an iron away.

As others have said, don't try to wick or suck the last bit of solder, if it doesn't come clean, *resolder* it with fresh solder and try again. Don't keep heating it, you need to develop short but deliberate timing. It's overheating that lifts traces (and kills cell seals....which is why the makers tell you not to solder on them...).

After you get past cleanness and flux, soldering is all about controlling heat.

Doug Owen

Excellent tips in this thread! I'm learning alot so thanks everyone for contributing the fruits of their hard-earned experience.

Bullzeye,
I use rosin-core solder but extra flux is good insurance in going the extra step since I can apply it right after I clean the area to be soldered.

Pila_power,
Good point about the heat. That copper braid transmits heat fast! I use orange solvent to clean flux residue.

JTR,
Great stuff!

Foxx,
I have sanded residue after solder removal. Personally, I'm not adept enough to cut solder off of a cell without often slitting the shrink wrap.

Doug,
Yes, timing is key in any hot operation related to batteries. Critical.

Good stuff, everyone.
Wilkey

Lot's of good information put forth. I have been doing a lot of reading from Web Sites regarding Soldering Techniques, some are quite descriptive. Unfortunately I could find any Alkalines laying around the house new/old, are they not Dinosaurs /ubbthreads/images/graemlins/grin.gif

I will maybe by a two pack of D Cells just to practice on. I expect delivery of the GP3700 Sub-C's in todays mail /ubbthreads/images/graemlins/smile.gif

I have put plenty of solder blobs on nimh cell phone batteries and my advice is this: if you can get at it well it is better and easier to use sandpaper or a file or even a fingernail emery board to sand down excess solder than to try to wick it off. If you want to remove solder completely and have a large amount of it, apply fresh solder to your iron to clean it, wipe off the solder and let the iron pick up as much solder as it can, shake the solder off the iron and/or wipe it and do it again if it is still a large amount. You can use a solder sucker if you have one in place of this also. After you get a lot of the solder then go use your wick and sometimes it is better to start back from the end if you have a large blob as it will be able to wick excess solder and heat in both directions. Cut wick off often when it feels stiff even if it doesn't look shiny sometimes the heated flux can foul up its ability to wick some. If you are used to a certain size iron for soldering/timing heat on a joint and have a slightly larger iron you may find it more useful for desoldering using wick or a solder sucker. I find desoldering goes quicker than soldering as you do not worry about the joint or coverage.

If you are concerned about overheating components while desoldering you can use a wire touching the leg, aluminum clips, forceps or even a pair of small needlenose pliers with a rubber band around the handles to hold it on the component.

As for batteries If I am soldering/desoldering I sometimes set one aside if I cannot get it done quickly and do another one waiting for it to cool down for a second pass.

Be patient if you cannot get the solder off the first time, don't just sit on the joint fumbling, stop and try again a few minutes later or go have a snack or something.

If you cannot afford solder wick you may get some cable tv coax and slit it open and use the shield as a cheap alternative. I haven't tried it but it should work better than nothing.

Quick method when you don't have proper materials.
::heat component and bang onto the table

Ahhh garage: the good ol' "Heat'n'Beat" technique!! /ubbthreads/images/graemlins/grin.gif

Believe it or not, another effective technique is to heat the part and wipe it with a dry paper towel. works suprsingly well.