Desoldering Braid: Tip - Trick

[woodscroller]

This may be posted already, so, forgive me if it's a repeat.

If you find that your desoldering braid isn't as effective as you'd like, apply a little flux to the braid/wick. It'll really suck!

The result for me was super clean holes and no need to chase or procure a stainless dental pick or needle the right size.

I used what was on hand which is just some RectorSeal paste flux commonly found in the plumbing section at your local hardware store for sweating copper pipe.

[LDSisHere]

Re: Desoldering Braid: Tip - Trick

Let me see if I can add some helpful information to your thread. It may help you and others out in the future.

Quality pre-fluxed braid should normally not need any additional flux; cheap, non-fluxed, and/or eBay braid will require flux and luck. I started off buying my braid at Radio Shack and Ebay because I did not know any other sources or that it mattered. I have since tried several brands sold by Mouser and Digi-Key all of which were far superior to what I had bought in the past but even between these there was a noticeable difference. If you use braid often and I think I do, it is well worth it to get the good stuff.

If you were cleaning the holes of a single-sided power supply PCB then you should never need to use a pick as these type of holes are likely the easiest of all to clean. This is not too hard even if you use cheap braid.

Computer motherboards are an entirely different beast, even with good braid and a good soldering station you can easily spend a lot of time, effort and unseemly vocabulary getting the holes cleaned out satisfactory even if you are experienced at it. If you bring a cheap iron and braid to the table you are just asking for trouble and lots of it.

With power supplies you just need to be careful not to lift traces while you are desoldering parts. This is a lot easier to do than it should be, as it seems they use the cheapest materials and thinnest copper they can get away with when they make them.

[mockingbird]

Re: Desoldering Braid: Tip - Trick

Yes, that Chinese eBay wick needs flux, but not Chemwick brand or any other quality product... Don't forget to clean off that plumbing flux with acetone, or else it will eat through solder mask.

[woodscroller]

Re: Desoldering Braid: Tip - Trick

The extra information is certainly appreciated! The extent of my electronics experience comes from modding IDM's for Power Strokes. That's when I bought my cheapo iron (25W), braid and 60/40 .032" solder from... you guessed it, RadioShack!

Did notice the PSU PCB was one sided but, the combination of the braid not being pre-fluxed and the low wattage iron seemed reasonable to be primary contributing factors of the problem. Of course, the lack of experience has nothing at all to do with it!!! The flux addtion took care of that though... straight away.

Sounds like I need to call on a local E-Recycler and scavenge a motherboard or 3 to practice on before working on my own. I did practice on an old satelite receiver box's board and had an oops where one side of a desoldered cap came back through the hole and tore the front side of the board. Cheap, Cheap, Cheap! They may as well used cardboard for the PCB.

I'm in no rush to recap my motherboard or out-of-spec 5VSB PSU. It'd break my heart to rush into it... destroying what I'm sure can be salvaged and used as a fully functional server/sandbox.

Better ($$$) equipment will just have to wait for now. And yes, I'm well aware of the old cliche' - "pay me now or pay me later."

[woodscroller]

Re: Desoldering Braid: Tip - Trick

Yes, that Chinese eBay wick needs flux, but not Chemwick brand or any other quality product... Don't forget to clean off that plumbing flux with acetone, or else it will eat through solder mask.

OHHH! I didn't know that - Thank you!

In this case though, as soon as I got the wires of my power supply, it took a bath with my homemade cleaner, rinsed with super hot water and blown with the compressor... followed by a sun-tanning session.

Curious though, what is it with the 'plumbing' flux that's different? Or, is it that even flux-core solder would do the same?

[mockingbird]

Re: Desoldering Braid: Tip - Trick

The plumbing flux is acid based, "No Clean" flux is rosin based -- not as corrosive.... Go figure what the difference between RA, RMA, and "No Clean" is though, I still personally don't understand. I like to always have a tube of RA core solder, I think RA is stronger than no clean so I use it to make lead-free easier to desolder, but don't quote me on that. Interestingly, the fumes from the RA solder smell and look a lot less harsh than the no clean fumes...

[woodscroller]

Re: Desoldering Braid: Tip - Trick

Ah. I'll have to look up the MSDS for this flux I used. IIRC, I have some liquid flux, somewhere... in the blackhole of my shop.

Will certainly look into better flux alternatives and solder too.

[severach]

Re: Desoldering Braid: Tip - Trick

They are all acid based. The difference is what temperature are they active at. Plumbing flux is very strong but the drawback is that it is still active at room temperature so it will continue to eat through stuff if not cleaned off. Rosin flux is made to be much milder. It won't eat through the corrosion as rapaciously as plumbing flux will but Rosin flux is almost inert at room temperature and doesn't need to be cleaned.

Cleaning flux is a sign of good work quality so should be done whether or not it is of the "no clean" variety.

[mockingbird]

Re: Desoldering Braid: Tip - Trick

I'd like to know what is in that flux cleaning spray and then order that base ingredient... Acetone and alcohol kind of work, but don't completely clean off no-clean flux.

[ratdude747]

Re: Desoldering Braid: Tip - Trick

I'd like to know what is in that flux cleaning spray and then order that base ingredient... Acetone and alcohol kind of work, but don't completely clean off no-clean flux.

Same here... Hence why for personal stuff I never clean no-clean. I know, I'm a noob for that... but I'm too lazy/cheap. If it's being showed off or is for somebody else, I clean it when I can.

[Longbow]

Re: Desoldering Braid: Tip - Trick

While the soldering braid should have active flux, it is a typical problem with practically every type. For new equipment, dipping the end of the braid in liquid solder (rosin) will bring it back to life. Or, you can brush the liquid solder onto the pcb connections where you are working.

It can be a mess, but dry braid is useless for desoldering. On older equipment the solder pads have a layer of oxidation that is difficult to break through even with rosin flux. It is not the officially sanctioned method, but the acid core flux solves the problem. Most of the time the older equipment will be point to point and the type of flux is of little importance. On a pcb, cleaning the flux is easy after you are done soldering, and is good practice no matter what type of flux is used.