Strongest flux remover - Page 1
Forum section: electronics / projects

author: mladen82
author_rank: Contributor
timestamp: November 13, 2016, 10:58:09 am
content: Hello everyone!I doing some repair&rework with electronics and until now i used isopropyl alcohol for cleaning flux residues from soldering, but realized that i need a stronger cleaner for harder baked-on flux residues.So i bought Microcare Vericlean flux remover (aerosol) but i was dissapointed with results, even worse than isopropyl. Let assume that i bought weaker Microcare flux remover, they have stronger removers also but there are many other manufacturers also (Techspay, MG Chemicals, Chemtronics, ACL Staticide,3M, Electrolube and others ) and other formulated flux removers (chemical ingredients).So my question is anyone tried some good strong flux remover for manual use as i don't want to make mistake again.Thanks in advance.

author: German_EE
author_rank: Super Contributor
timestamp: November 13, 2016, 03:01:46 pm
content: Careful use of acetone may work but please be aware that this will attack some plastics. Failing that, go back to IPA but use an ultrasonic cleaning bath.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: November 13, 2016, 04:15:02 pm
content: Quote from: German_EE on November 13, 2016, 03:01:46 pmI agree. Acetone dissolves it all, but unfortunately, also epoxy, so your PCB may suffer a bit. At the very least it might give an ugly finish.

author: N2IXK
author_rank: Frequent Contributor
timestamp: November 13, 2016, 04:57:31 pm
content: DCM does a decent job of removing old baked on flux, but is toxic, and even worse on plastics than acetone. Use only in a well ventilated area or outdoors.

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2016, 05:48:54 am
content: I would use acetone or lacquer thinner. For something a little less aggressive and less expensive, you might also try mixing acetone with IPA.

author: Someone
author_rank: Super Contributor
timestamp: November 14, 2016, 06:43:27 am
content: This stuff will take 'most anything off without damaging boards or components:http://www.electrolube.com/products/cleaning/swas/safewash_range_-_aqueous_cleaning/They have less aggressive options but gloves and safety glasses are needed for most of the rapid cleaners.

author: cat87
author_rank: Regular Contributor
timestamp: November 14, 2016, 01:02:34 pm
content: Unfortunately, nowadays, almost all commercial PCB cleaning products are useless. This is because of all that eco-friendly stuff, that's going around. For industrial Branson cleaners, you could get some really nice solvents that did away with the flux in about half an hour. But after those were considered to be carcinogenic, they were replaced with something resembling tap water, that's eco-friendly and triple the price of course....and of course they didn't work, meaning that the PCBs had to be soaked in the stuff for about 3-4 hours.As mentioned in other posts, the really cool stuff is either IPA or DCM. Acetone, not so much, because depending on the components you have and the PCB itself, things mightOf course, for making these even more effective, the aforementioned chemicals should be used with an ultrasonic bath or the classic paper towell and brush.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 14, 2016, 01:36:43 pm
content: Be sure you go to the capacitor sites and look at the application/tech data for al e-caps. They're usually pretty specific about what you can expose both regular and solvent-resistant caps to. Get a few of the wrong molecules in there, and they degrade pretty quick. I use IPA and a tooth brush and most boards come clean after a few minutes. I've used stronger solvents on things like old Dynaco boards that seemed to be dipped in flux, but keep the wet time to a minimum and use compressed air to get the stuff out from under parts and anywhere else it can hide. Most boards get a soap and water cleaning, rinse and compressed air dry after that.Be careful with clear wrapped polystyrene caps too. They may look fine, but then craze and fail days or weeks later after solvent exposure.Decades ago we used some aerosol products that were probably methylene chloride or some other horrible stuff. They were deadly but sure worked great. Freon TE-35 was also great stuff and didn't touch plastics, but destroyed the ozone layer.

author: wilhelm
author_rank: Contributor
timestamp: November 14, 2016, 02:08:04 pm
content: I use a 1:1 mix off acetone and IPA. Or add acetone in the IPA untill you get a good removal.

author: Pjotr
author_rank: Frequent Contributor
timestamp: November 14, 2016, 03:03:38 pm
content: For real hard baked flux I use methylene chloride. A tad bit more aggressive stuff than acetone but less flammableUsed with care in a well ventilated room or fume-cupboard it isn't that dangerous, but ok, it is no stuff to work whole day with like those diy surf board guys do. Acetone and methylene chloride can dissolve some plastics but most electronic PP, PE, phenol and epoxy based parts have a good resistance to it. Occasionally some kinds of solder masks will weaken, especially those older laminated-on ones. Modern (Chinese) one doesn't bother. So be careful and try first and wear protective gloves!

author: nanofrog
author_rank: Super Contributor
timestamp: November 14, 2016, 03:18:46 pm
content: I home brew mine.Primarily it's just denatured alcohol (Kleen Strip brand I buy is ~50/50 mix of ethanol & methanol). But if I need something more aggressive, I add 20% xylene by volume, and in a pinch, I add some acetone if needed. And all of this stuff can be found in a local paint department/store.

author: KL27x
author_rank: Super Contributor
timestamp: November 14, 2016, 08:37:31 pm
content: Strongest flux remover depends on the flux. (+1 on acetone and IPA mix, though, for general use) And a small paint brush with the bristles cut down. Or a toothbrush.

author: CraigHB
author_rank: Regular Contributor
timestamp: November 14, 2016, 09:01:51 pm
content: I just drop my boards in a tub of IPA and brush away the baked on crud with a flux brush. For stubborn flux residue I use contact cleaner. Works well for me so that's what I stick with. I keep a container of acetone to use when I need it, but it evaporates really fast and is highly flammable. Don't really like it for cleaning, mainly use it as a solvent for cyanoacrylate glue. It also eats some plastics. I'd be concerned with it possibly going after component packages. I haven't heard of using this DCM stuff, will have to look it up.

author: nanofrog
author_rank: Super Contributor
timestamp: November 14, 2016, 09:34:50 pm
content: Quote from: CraigHB on November 14, 2016, 09:01:51 pmDCM = dichloromethane (or methylene chloride). Based on my knowledge, it's usually the primary ingredient in chemical paint strippers and some degreasers, as well as used as a welding agent for some plastics.And according to Wikipedia, it's also used as a decaffeinating agent for coffee and tea.

author: Pjotr
author_rank: Frequent Contributor
timestamp: November 14, 2016, 09:59:30 pm
content: Another tough cleaner when IPA doesn't help is "PVC cleaner", i.e. Tangit PVC-U/C ABS from Henkel. It is primarily used for cleaning PVC plumbing pipe before cementing. Available from most DIY stores. It is a mixture of acetone and butanon (also known as MEK). Same precautions hold as for acetone and methylene chloride.

author: timb
author_rank: Super Contributor
timestamp: November 15, 2016, 12:26:16 am
content: Butane works as well for spot cleaning lumps of old flux, but be careful if you're applying it from a pressurized can, as it will come out *very* cold, which can potentially damage some types of electrolytic capacitors and also give you frostbite.It evaporates quickly and is obviously flammable, so use it in a well ventilated area! (Many years ago I watch someone light up a cigarette while attempting to make BTHO [Butane Hash Oil]; he spent weeks in a burn unit and required several skin grafts.)

author: helius
author_rank: Super Contributor
timestamp: November 15, 2016, 12:32:50 am
content: Chemtronics Max-Kleen Lectro-Solv is probably the strongest plastic-safe flux remover. It also seems to be discontinued, as trichloroethylene is believed to cause cancer.You can find the similar, but slightly less powerful tetrachloroethylene in several cleaners such as CRC Brakleen and Lectra-Motive. I don't know if they are specified to be safe on plastics.

author: Someone
author_rank: Super Contributor
timestamp: November 15, 2016, 02:06:22 am
content: Quote from: cat87 on November 14, 2016, 01:02:34 pmGet in contact with electrolube, they have a range of cleaning solutions that will take off flux in minutes.

author: Cerebus
author_rank: Super Contributor
timestamp: November 15, 2016, 02:59:18 am
content: Quote from: Pjotr on November 14, 2016, 09:59:30 pmBe aware that MEK (Butanone, Methyl-Ethyl-Ketone) is strongly absorbed by some plastics, causing them to swell. It was (is?) sold to litho printers as "blanket restorer" for putting a bit of bounce back into tired rubber printing transfer blankets and is the only thing I know that will remove hardened, long dried printing ink. Used judiciously it is an excellent solvent. It is significantly higher fire risk than acetone - it has vapour creeping qualities similar to ethyl ether.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 15, 2016, 03:55:53 am
content: The best possible ones will be the most toxic or flammable ones. Needless to say, they will likely affect components or board materials...DCM: swells or dissolves almost every organic polymer, including epoxy and silicone. Best avoided.Light ethers (usually diethyl ether): probably fine, but highly flammable and an organic peroxide hazard (if you see crusty deposits in the bottle... call the bomb squad).Light CFCs: chloroform (anesthetic), carbon tetrrachloride (carcinogenic), trichloroethylene, 1,1,1 trichloroethane, others. TCEs in particular are exceptional (leaving most plastics alone, similar to acetone), but have fallen out of use because, you know, the ozone layer and such...Acetone, ethanol, isopropanol: not as strong, but leaves most plastics alone, and are environmentally friendly and low-toxicity (if still rather flammable).IPA with base and surfactant: usually detergent and ammonia. Rosin is organic acid, so this is a killer combination! (This is probably most of what that SafeWash stuff is.)Heating, agitation (or better yet, sonication), and multiple wash-rinse cycles will do the best job.Mind that you can't really wash under flat-mounted chip components. If you need very low leakage, consider routing slots under those spaces, or adding vent holes/vias to allow solvent through.Also try not to cook the piss out of the rosin. The longer you keep it hot (and the dirtier your metal surfaces are), the more insoluble (or slowly soluble) gunk it leaves.Tim

author: calexanian
author_rank: Super Contributor
timestamp: November 15, 2016, 04:54:18 am
content: As i just mentioned in another post. Non chlorinated brake cleaner can remove the most baked on RA flux. Like any solvent some parts may melt or become discolored. Brake cleaner, toothbrush, and a flush with deionized water and you have the cleanest board you ever saw.

author: David Hess
author_rank: Super Contributor
timestamp: November 15, 2016, 06:57:13 am
content: Quote from: T3sl4co1l on November 15, 2016, 03:55:53 amTCEs were great for flux removal.Toluene mixed with isopropanol may be better than acetone mixed with isopropanol and is or was a common flux thinner (I have a bunch of bottles of 50/50 toluene/isopropanol intended as such) but I did not suggest it because the availability of toluene has become restricted. This suggests that xylene which is readily available mixed with isopropanol would also be good for rosin flux removal (and thinning) but I have not tried it.

author: CraigHB
author_rank: Regular Contributor
timestamp: November 15, 2016, 03:32:29 pm
content: Good thing about CRC Brakleen is it's super cheap, seeing it for like five dollars a 20 oz spray can shipped on eBay. I use CRC QD Electrical Cleaner when IPA can't get residues. It's better than twice the cost of CRC Brakleen. The QD Electrical Cleaner does work well, but it's a bit pricey and I go through it kind of fast. Looking on the label it says it contains Hexane, Ethanol, and Diflouroethane. What's in Brakleen?

author: darrellg
author_rank: Unknown
timestamp: November 15, 2016, 04:49:05 pm
content: Trichloroethane is the best, if you don't mind that it's mildly toxic and illegal under the Montreal Protocol.

author: N2IXK
author_rank: Frequent Contributor
timestamp: November 15, 2016, 05:01:50 pm
content: Quote from: CraigHB on November 15, 2016, 03:32:29 pmCRC Brakleen comes in 2 varieties, the green can that contains perchloroethylene, and the red can, which is a mix of acetone, toluene, and methanol.

author: helius
author_rank: Super Contributor
timestamp: November 15, 2016, 05:39:00 pm
content: Quote from: N2IXK on November 15, 2016, 05:01:50 pmIt'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.

author: mcinque
author_rank: Unknown
timestamp: November 15, 2016, 09:01:30 pm
content: 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.

author: mladen82
author_rank: Contributor
timestamp: November 15, 2016, 09:27:31 pm
content: 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+dichloroethyleneShit, its some type of high tech chemical.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 15, 2016, 09:36:46 pm
content: 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

author: helius
author_rank: Super Contributor
timestamp: November 15, 2016, 10:10:34 pm
content: Technical Grade is the cheapest... Reagent Grade is more expensive, and Analytical Grade is the most expensive.

author: Bryan
author_rank: Frequent Contributor
timestamp: November 15, 2016, 10:15:44 pm
content: Quote from: helius on November 15, 2016, 05:39:00 pmLooks like they make 6 different products. two reds and 4 greenshttp://crcindustries.com/auto/crc-brakleen-brake-parts-cleaner

author: helius
author_rank: Super Contributor
timestamp: November 15, 2016, 11:17:19 pm
content: Quote from: Bryan on November 15, 2016, 10:15:44 pmNot 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.

author: LukeW
author_rank: Frequent Contributor
timestamp: November 16, 2016, 12:09:16 am
content: 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.

author: crispytato
author_rank: Regular Contributor
timestamp: November 16, 2016, 07:24:08 am
content: 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.

author: Jeroen3
author_rank: Super Contributor
timestamp: November 16, 2016, 09:13:49 am
content: 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.

author: plazma
author_rank: Frequent Contributor
timestamp: November 16, 2016, 09:38:51 am
content: Is perchloroethylene any good for electronics? I have a barrel of it.

author: Pjotr
author_rank: Frequent Contributor
timestamp: November 16, 2016, 11:26:40 am
content: Quote from: Jeroen3 on November 16, 2016, 09:13:49 amNot 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.

author: CraigHB
author_rank: Regular Contributor
timestamp: November 16, 2016, 04:33:27 pm
content: Quote from: Bryan on November 15, 2016, 10:15:44 pmThat'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?

author: helius
author_rank: Super Contributor
timestamp: November 16, 2016, 05:58:51 pm
content: Quote from: CraigHB on November 16, 2016, 04:33:27 pmThe 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.Quote from: CraigHBJewelry 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.

author: Pjotr
author_rank: Frequent Contributor
timestamp: November 16, 2016, 07:16:03 pm
content: Quote from: helius on November 16, 2016, 05:58:51 pmMost 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.

author: David Hess
author_rank: Super Contributor
timestamp: November 16, 2016, 09:04:02 pm
content: Quote from: blueskull on November 16, 2016, 08:31:04 pmThat 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.QuoteMy 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.

author: Cerebus
author_rank: Super Contributor
timestamp: November 16, 2016, 09:45:40 pm
content: Quote from: Pjotr on November 16, 2016, 07:16:03 pmI'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).

author: David Hess
author_rank: Super Contributor
timestamp: November 16, 2016, 11:32:47 pm
content: Quote from: blueskull on November 16, 2016, 09:21:07 pmI 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.QuoteI 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.

author: calexanian
author_rank: Super Contributor
timestamp: November 17, 2016, 04:28:13 am
content: 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.

author: Kean
author_rank: Unknown
timestamp: November 17, 2016, 06:36:25 am
content: 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.

author: calexanian
author_rank: Super Contributor
timestamp: November 17, 2016, 06:47:35 am
content: 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.

author: helius
author_rank: Super Contributor
timestamp: November 17, 2016, 03:09:21 pm
content: Do you need to wash soldering tips with water after using them with water-soluble organic flux?

author: CraigHB
author_rank: Regular Contributor
timestamp: November 17, 2016, 05:56:11 pm
content: 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?

author: timb
author_rank: Super Contributor
timestamp: November 18, 2016, 01:51:01 am
content: Quote from: David Hess on November 16, 2016, 09:04:02 pmThat'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.)Quote from: Pjotr on November 16, 2016, 07:16:03 pmI 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.)