Strongest flux remover

[helius]

CRC Brakleen comes in 2 varieties, the green can that contains perchloroethylene, and the red can, which is a mix of acetone, toluene, and methanol.

It's the other way around: all the green cans are non-chloroalkene based. The perc formula is in a red can, but I believe there is another type in a red can that doesn't use it.

[mcinque]

Trichloroethylene works very well and doesn't damage plastics. It's a "little bit" (ehm... stronger) carcinogenic and toxic but with proper ventilation and gloves doesn't kill so easily.

[mladen82]

First, thanks all for advices.
As most of you suggested definitely i will try combination of acetone and IPA first. 

I investigated little bit of what chemicals are mixed these powerful cleaners that have Microcare and the others.
These are mostly chemical like trans dichloroethylene ( group: organochloride). Also was looking to see for purchase this chemical and came to the conclusion that only 25grams of such type chemical costs around $100.
https://www.fishersci.com/shop/products/trans-1-2-dichloroethylene-99-stabilized-acros-organics-2/p-105404#?keyword=trans+dichloroethylene
Shit, its some type of high tech chemical. 

[T3sl4co1l]

Heh well... if you want a bottle of Technical Grade for the lab, you'd maybe buy it there.. but for an industrial solvent, yeah, there are better places...

Tim

[helius]

Technical Grade is the cheapest... Reagent Grade is more expensive, and Analytical Grade is the most expensive.

[Bryan]

CRC Brakleen comes in 2 varieties, the green can that contains perchloroethylene, and the red can, which is a mix of acetone, toluene, and methanol.

It's the other way around: all the green cans are non-chloroalkene based. The perc formula is in a red can, but I believe there is another type in a red can that doesn't use it.

Looks like they make 6 different products. two reds and 4 greens
http://crcindustries.com/auto/crc-brakleen-brake-parts-cleaner

[helius]

Looks like they make 6 different products. two reds and 4 greens
http://crcindustries.com/auto/crc-brakleen-brake-parts-cleaner

Not to mention CRC Lectra-Motive, which is essentially the same as the red can Perc formula!
There's a lot of catalog padding in these products; you'll also often find that companies will make a "flux remover" and a "degreaser" that have the same bill of materials.

[LukeW]

Personally I like MEK, applied by hand with a cotton bud, for spot cleaning of tough flux.

The relatively slow evaporation rate compared to acetone seems to be helpful.

[crispytato]

Where I live, a common solvent used for cleaning all sorts of stuff is methylated spirits, Meths. It's basically just denatured methanol or ethanol depending where it's bought. Seems to remove flux pretty well for me, even baked on nasty residue. Just need a small dish, a stiff brush, and a bit of scrubbing.

If that doesn't touch it, yeah, brakleen is good stuff. The one that I buy has the listed ingredients as Dichloromethane and Tetrachloroethylene.

[Jeroen3]

In order of aggression (and smell):
1. FluxOff (cramolin), it will even dissolve paints and smells awful. Use outside or in fume chamber.
2. Kontakt PC (Kontakt LR), reasonable result, with small brush, leaves white residue.
3. Microcare Vericlean, great mild cleaner to clean fully assembled stuff of wash off above residues.
Can be used to clean everything, which we use it for.

Do not forget that you can't use these on water soluble flux and pastes!

Best overall result I have had so far was with none of these, but in the ultrasonic cleaner. However, this required baking.
Fresh assembled and soldered smd board go in the ultrasonic, and emerge as if they came from the assembly house.

[plazma]

Is perchloroethylene any good for electronics? I have a barrel of it.

[Pjotr]

Best overall result I have had so far was with none of these, but in the ultrasonic cleaner. However, this required baking.
Fresh assembled and soldered smd board go in the ultrasonic, and emerge as if they came from the assembly house.

Not all components stand ultrasonic cleaning, like some oscillator crystals. Fresh soldered boards can be cleaned well with normal mild detergents like dish washing soap and a tooth brush. I usually put them into the dish washer with half a soap tablet for one-offs. Point here is to remove baked flux after rework that will not dissolve any more. That needs more tough stuff to swell and weaken it to be removed. Almost any solvent that weaken the baked flux will do. But unfortunately that are not the most healthy ones.

[CraigHB]

Looks like they make 6 different products. two reds and 4 greens http://crcindustries.com/auto/crc-brakleen-brake-parts-cleaner

That's pretty confusing.  Is there any issue with using the chlorinated stuff?  I just made an order for QD Electrical Cleaner, but when I run out I might give that Brakleen a try, it's so much cheaper.

I actually have an ultrasonic cleaner for cleaning my wife's jewelry.  Maybe I should give that a try.  Do you just fill the tub with IPA?

[helius]

That's pretty confusing.  Is there any issue with using the chlorinated stuff?  I just made an order for QD Electrical Cleaner, but when I run out I might give that Brakleen a try, it's so much cheaper.

The many varieties of Brakleen are a result of state and local ordinances regarding VOCs. There are really two main formulas, the original 05089, which is pure C₂Cl₄ ("Perc"); and the 05088, a mixture of MeOH, Me-C₆H₆, and various aliphatic solvents. The rest are watered down with acetone to comply with VOC limits.
Perchloroethylene swells plastics, especially ABS, polycarbonate, and rubber. It may seriously compromise the seals on electrolytic capacitors.

I actually have an ultrasonic cleaner for cleaning my wife's jewelry.  Maybe I should give that a try.  Do you just fill the tub with IPA?

Jewelry cleaners are usually too small to correctly suspend a PCB in the center, fully immersed. Absent a commercial cleaner, I would use DI water, denatured alcohol, and ammonia in about a 10:5:1 ratio. Commercial cleaners use non-volatile sequestering agents.

[Pjotr]

Perchloroethylene swells plastics, especially ABS, polycarbonate, and rubber. It may seriously compromise the seals on electrolytic capacitors.

Most solvents that came along here do swell rubber. I wondered how serious this is regarding seals of electrolytics. It will swell the rubber, but most will also evaporate very quickly. I doubt it will damage the rubber seals. Maybe if you'll soak them for tens of minutes? But then the printing on or sleeving is disappeared also.

[David Hess]

Just curious, does anyone has the intention to start a KS or IGG project building a reflux cleaner?

That would be fun but if you want to use it commercially, the local government may have something to say about it.

The ones I have used in the past had refrigeration coils at the top to prevent as little vapor as possible from leaving the tank.  Some had a little "waterfall" which poured into a smaller tank inside so there was a pool of continuously refreshed liquid solvent available for dipping.

As shown in the video you linked, they really do work like magic but temperature can be a problem and flammability can be a hazard because the cool solvents like TCE are banned.

For me, cleaning hard flux is not particularly bad, but the nightmare is dissolved flux will contaminate board and make it sticky. To get fresh solvent, I always have to waste a lot of solvent to keep flux concentration low.

My solution for this where the board needs to be really clean is to keep a squeeze bottle of the solvent to wash the board down as it is removed from the cleaning dish or tank.

[Cerebus]

Most solvents that came along here do swell rubber. I wondered how serious this is regarding seals of electrolytics. It will swell the rubber, but most will also evaporate very quickly. I doubt it will damage the rubber seals.

I'm not sure about that. There's a phenomenon I'm aware of from wood, where if a joint gets wet and swells then the parts that don't have room to expand get compressed. Then when the joint dries out the parts that were compressed take a 'set' from the compressed wet condition and voila, you've got a loose joint*. Wood's not the only material that has this property, I've seen it happen in plastics and I wouldn't rule it out as a possible mechanism in rubber without either experiments or further research.

*This is exactly why that hammer you left out in the garden overnight has a loose head next time you get it out to use (once it's had time to dry out properly).

[David Hess]

Is it possible to build a sealed container with pressure equalization to contain most of the vapors and use environmentally friendly solvents like IPA or acetone?

I suppose but one of the major features of vapor cleaning as shown in that video is that the pure vapor condenses on the item to be cleaned and runs off carrying contaminates with it.  This also transfers heat to the item and the process stops once temperature equilibrium is reached.

I'm not looking for any ozone depletion solvents or carcinogen ones, let along toxic ones.

I am currently using a solvent spray can (MG 413B) to do final touch ups, but the cost is too high and I don't want to get solvents on my hands. My professor has a pair of flaky hands and he believes it was caused by extended exposure to IPA. I'm moving to more skin friendly acetone, but I still don't want to get that stuff on my hand. Gloves are not an option as I need to precisely feel and rub the parts to ensure best cleaning effect.
With an automated reflux system, I can just leave it there for tens of minutes without my hands in the container.

I would not want to routinely get my fingers into the vapor no matter what the solvent is.  IPA and acetone will handily degrease your skin turning it white and flaky.

If you are just doing small parts and small lots then use a beaker as shown in the video and be prepared for a fire if the worst happens; it is not *that* dangerous unless you panic and spill the cleaning fluid.  Scrub with a tool like a toothbrush or your gloved fingers.  Maybe get or make an open shielded workstation so your face is not exposed to go with the fume hood if you are working indoors.

Offhand I do not know what nonflammable solvents replaced TCE but I am sure that information is available online.  I get by with my large heated ultrasonic cleaner and rinsing with solvent.

[calexanian]

Any wash down rated capacitor worth it's salt should have an EDPM seal. Should not be effected by brief exposure to any of the common solvents or cleaners save heavily chlorinated ones which are mostly banned now anyways.

[Kean]

As @Someone mentioned above, have a look at Electrolube Safewash SWAS.

It is specifically formulated for dissolving and absorbing modern difficult to clean fluxes, and is going to be less toxic and harmful to the environment than many other chemicals mentioned above.  I've been trialling it as an alternative to IPA, and so far it has worked really well in the ultrasonic cleaner without any of the manual brushing that IPA would need. 

Just make sure your rinse it well, and don't leave things soaking too long.  I left an unpopulated PCB in it by accident overnight (cleaning off excess paste after misaligned stencil) and it started removing the gold and tin plating on the exposed traces.

[calexanian]

I do like organic flux solder. Generally its water clean. Super active though. You have to make super sure its all washed off or bad times ahead. Fortunately all it takes is water! It does have a rater unpleasant odor though, and you really really don't want to breathe the fumes. I don't bother with the fume extractor. I go straight to the fan to make sure I am not breathing any of it. makes a nice shiny well flowed joint almost like RA flux though. 

[helius]

Do you need to wash soldering tips with water after using them with water-soluble organic flux?

[CraigHB]

I was just cleaning some PCB assemblies that came from China. I don't know what they're using as a flux base, but that stuff is really hard to get off and of course they don't clean boards properly.  I run into this quite a bit.  It's probably not a functional issue, but it bothers me all the scum they leave on boards.  I have zero issue removing the flux from my own boards, but that stuff they use in production is really hard to get off of there.  It's like a gum and nothing will dissolve it.  Any trick to getting that stuff off?

[timb]

My solution for this where the board needs to be really clean is to keep a squeeze bottle of the solvent to wash the board down as it is removed from the cleaning dish or tank.

That's what I do too. I keep a large spray bottle full of 90% IPA that I use for a final scrub and rinse.

Basically I've got a large borosilicate glass container (about the size of a cake pan, only much taller) that I keep filled with "dirty" IPA. I soak boards in it for 15 minutes, then scrub (while they're submerged).

When I remove a board from the dirty pan, I let it drip for a few seconds, then spray throughly with clean IPA from the spray bottle (hold the board overtop of the dirty pan when you spray, that way the IPA will fall into the pan and keep it full; better than letting it go down the drain).

Then I let the board soak for another 15 minutes in a second container of IPA (the "clean" pan). I give it a quick scrub in this pan, just like before and then a final spray rinse.

Then, simply allow it to air dry for 15 to 30 minutes. (Sometimes, if I'm in a hurry I'll hold it in front of the in-wall heater in my bathroom for 60 seconds, which pretty much evaporates it all instantly.)

(Note: I also have another spray bottle with a 5:1 mix of distilled water and IPA, it's great for rinsing plastics and stuff sensitive to pure alcohol.)

Most solvents that came along here do swell rubber. I wondered how serious this is regarding seals of electrolytics. It will swell the rubber, but most will also evaporate very quickly. I doubt it will damage the rubber seals. Maybe if you'll soak them for tens of minutes? But then the printing on or sleeving is disappeared also.

I can attest to the fact that BrakeKleen swells rubber *very* quickly! Years back I bought a 2001 Suzuki SV650; I was in the process of overhauling the brake system and, after completely disassembling the calipers, decided to soak them in a coffee can full of BrakeKleen. That worked beautifully and they came out sparkling.

I decided I would dip the rubber nipples and o-rings into it as well, just for a few seconds, to remove the brake fluid on them. Big mistake! They instantly started to swell and became slick as some of the rubber dissolved.

(It wasn't a big deal for the o-rings, as you should always replace them anyway, but the nipples could have been reused.)