What to clean a PCB with after soldering?

[NeilP]

Have been wondering about this for a while, but never got round to asking

What to use to clean a board up after soldering...something that cleans off all the old flux etc. have tried aerosol electrical contact cleaner but it does not seem that effective

 

[Toorbough ULL-Zeveigh]

i always thought aerosol flux remover is a mix of acetone & isopropyl alcohol but acetone isn't safe on plastics so maybe not or maybe not anymore.
either one by itself should work to some degree with acetone being the more effective of the two.
have no idea if it works on Pb free, never used the stuf.

[youtube]7zbIFxIqlUs[/youtube]

 

[amberwolf]

Depending on what else is on the board, very high percentage Isopropyl Alcohol should work, though you may have to "scrub" at thick spots with a q-tip or let the alcohol soak on it a bit.

Failing that, Denatured Alcohol can work, but it is also nearly certain to take the markings off anything that's painted on (rather than laser etched), and may damage plastic surfaces, LED housings, etc.


There are a few citrus cleaners that will work, too. I am not sure, but I think the name of one I used once was CitraSolve or something similar; it comes HIGHLY concentrated and a tiny bit mixes with water and makes a lot of cleaner. More concentrated works better on this stuff.

 

[NeilP]

OK, thanks. I'l have a look around

 

[ambroseliao]

Watching that video, the primary ingredients are acetone and alcohol. You can get both of those at your local hardware store in large quantities for not much money.

Be careful with Acetone though. Use it in a well ventilated area!!! You've been warned!

 

[rebelpilot]

A good stiff toothbrush really helps with any solvent.

 

[heathyoung]

Laquer thinnners (ie. prepsol etc) - and a toothbrush. Works brilliantly. Not for the lead-free eco-weenies though, the fumes are err... :lol:

 

[DAND214]

Has anyone tried Brake Clean. It's ok if there is no plastic around.

Dan

 

[Kingfish]

My little story:

Not long ago whilst doing the battery harness upgrade (still in progress) I noticed that my front controller had 12-AWG battery wires, an indication that I might not have done the Current Mod whereas the rear controller (my first 12-FET that I purchased back in 2010) is fully upgraded and sports the 10-AWG battery wires. Like the dirty back closet that’s just nagging to be cleaned, I suspected well the task before me. <sigh>

The bike is already ripped apart, electrical guts everywhere; might as well take the plunge as long as I’m sitting next to the pool. Removed the controller, opened it up and I was correct: No Current Mod. I can't believe I didn't do this before my road trip last summer.

• The Current Mod is taking a stock controller and ripping the tiny copper wires off the power traces and replacing them with something like 12- or 10-AWG wire (twisted or solid; whatever is handy). The mod is concluded when the battery wires are upgraded to 10-AWG. Done.

Except for the flux. :|

I did a quick search and found that Acetone is useful. I checked my cupboard of chemicals; nearly enough ingredients here to make meth – but no Acetone. Shock and dismay. To the Internet: What’s that site… EHow.com? I think it’s more like E-Not-How.com. They suggested Baking Soda and hot water. OK, I’ve got that. Pasted away at the board, working up a sweat grinding it in with an old toothbrush. Warsh it off: Nope. Flux still there, but the rest of the board is so pearly clean you could eat off of it.

What’s next? Hmmm, this thread says Alcohol. That was the first thing I tried. Already knows that won’t cut it. :?

What else do I have? Wot’s this? Hmmm, Mineral Spirits. To the Web: Some guy professes that Mineral Spirits will clean flux off, and to follow that with Alcohol and drip-dry. I can do that. Opened the Mineral Spirits and whew! hit the fan switch and opened the winders. Made quick work first dribbling the Spirits of the Material World onto the board so it good and soaked. Dangerously armed with an old toothbrush I scoured away at it, being careful not to breath in too deeply. Once again, I dribble spirits onto the board: Ah HAH! Murky brown residue is draining away; it’s working. Again, I dash away at the board. Inspection: Heavy build-up is gone. Splashed the board with some Isopropanol, and decided to warsh that off with hot water which dries quickly.

Inspection with the 5X OptiVisor: All build-up is exceptionally removed. The board is brilliantly bright and spiffy… no doubt thanks to the Baking Soda. I found a couple tiny spots that needed a little scrap – but that’s under magnification. Good to go!

Conclusion: I’d say if you haven’t got Acetone, try the Mineral Spirits and flush with Alcohol. And if you want to eat off of it later, use the Baking Soda.

Supper time, KF

 

[amberwolf]

Isopropyl alcohol works well for small amounts of fresh flux; it is not all that great for large amounts or old flux, unless you soak it.

Denatured alcohol usually works on all of the above, but it is just about as stinky/nasty as mineral spirits, and it'll eat into some paints (krylon) and plastics (anything xylene or toluene would dissolve, so will denatured alcohol).

 

[Kingfish]

Thanks AW. I was actually looking for the Toluene; thought I had some along with the Acetone, but evidently not.

I have both Denatured and Isopropanol (Rubbing Alcohol); given the wide variance on how these products are manufactured, it is difficult to know which will work best. I used the latter on this board, however – next time I shall try the Denatured to see if there is better success.

12-FET Lyen Controller after applying the Current Mod yesterday using 63/37 solder.

That board is so bright; I need sunglasses to look at it! 8)
~KF

 

[salty9]

They sell 2 concentrations of isopropyl alcohol - 70% and I believe 90%. The 90% has more solvency for organics.

 

[NeilP]

How about 94%abv ethanol? would that work..Not tried it yet. I have the ethanol, but no dirty boards at the moment

 

[Kingfish]

After my last post I went back to that board and dabbed a bit more solder into certain paths to beef them up, and I used the Denatured Alcohol with a Q-Tip for cleanup; it defintely removed the light stuff better than Isopropanol, but build-up areas need more serious effort.

I'm pretty sure some of the rot-gut solventy homebrews I've judged over the years would make wonderful cleaners
~KF

 

[Kin]

On tuesday I can look up what we use at work...there's this very nice german flux remover, which is much gentler than typical flux remover, but still very effective. We switched to it after one guy passed out on the bathroom because he was cleaning the with the normal flux remover noxious stuff without even the door open....


but if you're just talking about the rosin core to typical solder, you don't *need* to clean that, the way you need to clean stronger flux. As far as I'm aware, it doesn't continue to eat much over time. But just for looks, I usually use isopropyl alcohol and a painting brush cut short (essentially a toothbrush).

 

[scriewy]

Spirits = alcohol ?
i use the ones pharmacy sell 96%, they are more clean.

same as making simple flux, chip off of some pine tree some rosin and mix with alcohol 96%.

my phone ones fell in the shower, all pcb and contacts soacked through, water in lcd touch screen resistive layer, it died and wouldnt power on.
usually companies dont bother fixing water accident coz contacts erose in few minuts from electrolysis or they erode by the time it drys off naturally and game over.

i didnt wanna get refurbrished phone coz you never know the history with previous owner maybe some 1 stuffed it in a pussy coz it vibrates, so i dipped it whole in 96% coz it bonds with water by Hydrogen connection and v.d.v. And when evaporates takes the water with it (plus alcohol evaporates in a jeeffy).
still using it.

 

[Kin]

Ok, so it turns out at work we just use regular "GlobalTech solder paste and flux remover"

It's made with "Glycols, Aliphatic glycol Ethers, N-Amino Ethanol" by JNJ Industries.

The german stuff I was thinking of was actually the flux, "Kester 951 Low Residue Soldering Flux" and this allowed us usually not to have to use the heavier duty solder cleaning stuff. Instead, we just use alcohol now because the Kester stuff can almost be left on the board by itself. Only on a few items do we use the hard core high residue flux that requires the globaltech flux remover.


With rosin paste/flux though, there's less to worry about than with explicit additional flux, so yeah. Alcohol/Spirits all the way.

I was replacing some fets and I noticed, although I said you don't really need to clean flux that's within the solder, on these boards with so much solder in the traces the stuff does gunk up. So i used alcohol and some stiff bristles to clean things up.