Cleaning Flux For Printed Circuit Board? - Page 1
Forum section: electronics / beginners

author: sparkyinak
author_rank: Contributor
timestamp: August 30, 2025, 09:07:21 pm
content: I thought I posted this earlier and should have posted by now but I cannot find it anywhere so I apologize if it does appear later.Can I use contact cleaner to clean excessive flux from a soldered circuit board? If not, suggestions?I recently made up my first printed circuit board in 40+ years. After soldering it all up and started testing it, I was getting very low resistance readings, much lower than they should be. Given that my project will be exposed to up to 277 VAC, every thing needs to be spot on prior to putting power to it. I tested each component prior installing them and my math has been checked and rechecked. I then questioned my meter being it was brand new and never really tested it yet being it will be dedicated to my work (play) stations. It did checked out. I double checked for shorts in my soldering (which not the prettiest) but found no issues so I started to think I had a bad board.I got on the internet and learned that flux can be conductive. Given the amount of soldering and the circuitry’s compactness, I was pretty sure I found my issue. I dug a little deeper and a couple articles stated just run the boards under water and scrub a little. Being an electrician by trade, that didn’t sit well with me. I did find some flux cleaner online but where I live in Alaska, it would have been ridiculously expensive to ship to me. I have some and locally available relatively cheap. Thank you in advance

author: Benta
author_rank: Super Contributor
timestamp: August 30, 2025, 09:10:40 pm
content: Isopropylic alcohol (aka isopropanol or 2-propanol) and a soft toothbrush.

author: tooki
author_rank: Super Contributor
timestamp: August 30, 2025, 09:26:11 pm
content: Quote from: sparkyinak on August 30, 2025, 09:07:21 pmNo, contact cleaner is not a strong solvent.Quote from: sparkyinak on August 30, 2025, 09:07:21 pmWhile electronics aren’t nearly as sensitive to water as people think they are, most fluxes aren’t water-washable, so this simply wouldn’t work unless you use a saponifying cleaner. More on that below,Quote from: Benta on August 30, 2025, 09:10:40 pmIsopropyl alcohol (IPA) is… ok, but not the best. Many fluxes expressly say that IPA is not adequate for cleaning them, and this agrees with my own experience.Ok, so what can you use?A blend of isopropyl with a bit of acetone will work MUCH better than straight IPA. (Just be careful, because some plastics are sensitive, and acetone also washes off the printing from some components.) Ordinary brake cleaner also works quite well, though you might want to give a final rinse with IPA afterwards, just in case the brake cleaner solvent isn’t perfectly pure.Basically, a solvent blend of some alcohol plus some hydrocarbon is ideal. (I use ethanol because it has a nicer odor than IPA, and because we have it readily available at work. For most people, IPA is easier to get than ethanol, so use whatever is easiest. Just not methanol, which is toxic.) Orange terpenes are also quite effective, and used in some commercial flux removers.If you want to go water-based, many people report success using ZEP floor wax stripper, because it’s chemically practically identical to commercial flux saponifier. If you have an ultrasonic cleaner, this works even better.(My everyday flux cleaner at work is a blend of ethanol and acetone. For things that are sensitive to acetone, I use Electrolube LFFR, or the water-based SWAS in the ultrasonic cleaner.)

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: September 06, 2025, 05:38:13 pm
content: Isopropyl alcohol (90% or higher) with a toothbrush scrub will work fine.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 06, 2025, 06:26:18 pm
content: ZEP heavy duty floor stripper diluted 1 part Zep to 3 part total with water. Rinse with DI water.

author: tooki
author_rank: Super Contributor
timestamp: September 06, 2025, 06:28:57 pm
content: Quote from: ahsrabrifat on September 06, 2025, 05:38:13 pmAs I already said: not for all fluxes. So you can say itmightwork fine, but not that itwill.

author: NE666
author_rank: Frequent Contributor
timestamp: September 07, 2025, 08:34:49 am
content: I use Electrolube's Fluxclene in conjunction with a soft toothbrush. I then rinse with IPA and dry with an air duster.I've yet to have any issues with it.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 07, 2025, 09:22:48 am
content: Quote from: NE666 on September 07, 2025, 08:34:49 amQuote from: Fluxclene SDSInteresting. it's IPA + a hydrocarbon + an ether alcohol (aka propylene glycol methyl ether). The later boils at 120°C. Ether alcohols have interesting, sometimes almost unique solvent properties and are used often in paints and finishes. ZEP (and Kester's similar flux remover) have butoxyethanol, which is in the same class of solvents. That boils at a higher temperature, but is used in water, so one can rinse in water and not have to wait for it to evaporate.

author: Traceless
author_rank: Frequent Contributor
timestamp: September 07, 2025, 10:27:41 am
content: As others suggested IPA should work. Personally I'd also recommendContact LRhowever this seems to be a product localized to the German market. The vendor "Kontakt Chemie" is however part of CRC Industries, which are located in Pennyslvania so maybe they sell it in the US under a different name using the CRC brand?Some of the contents listed in the datasheet:2-PropanolHydrocarbons, C6-C7, n-alkanes, isoalkanes, cyclic compounds, <5% n-hexaneEthanolDimethoxymethane1-ethoxypropan-2-ol; 2PG1EE; 1-ethoxy-2-propanol; Propylene glycol monoethyl etherMethanol

author: paulca
author_rank: Super Contributor
timestamp: September 07, 2025, 10:32:44 am
content: 95%+ IPA and an toothbrush.However, there is a technique. The IPA dissolves the flux, so if you just let the IPA evaporate away it will leave a thin coat of flux on everything, the board will look clean, but be dull and sticky.To fix, put a good amount of IPA on, brush it around with the brush and then immiedaitely soak it up with a paper towel. Repeat if necessary to get a shiny clean board.

author: Traceless
author_rank: Frequent Contributor
timestamp: September 07, 2025, 11:35:01 am
content: Quote from: paulca on September 07, 2025, 10:32:44 amThat is some very good advice of paulca, since the solvents don't make the flux magically disappear.In case you are working with smaller SMD components and use non-liquid, ideally tacky flux I'd start cleaning *without* solvent using a cotton bud. The tacky flux sticks to the cotton buds much better than to the PCB so you can remove most of the flux off before dissolving it and spreading it around the entire board. Once you removed the majority you can use solvent to tidy up the remains.

author: Ian.M
author_rank: Super Contributor
timestamp: September 07, 2025, 12:04:19 pm
content: Blotting with a paper towel or lint free wipe can be a PITA unless you are only doing a small area. For whole board defluxing, brush around plenty of solvent (denatured alcohol, IPA, or more specialised flux removers) as Paulca recommends, then I typically tilt the board vertical and let the flux-loaded used solvent run off, blotting the edge on a pad of paper towel so I don't get sticky areas near the edge due to drips that didn't quite make it. If you can spray on more solvent while its vertical once most has drained, that helps significantly. Also, immediately afterwards blot the brush on more paper towel so you aren't bringing so much flux back to the board when you repeat to get it cleaner.Has anyone got a UK/Europe equivalent to ZEP heavy duty floor stripper, as availability of US products this side of the pond is abysmal especially with the current trade issues?

author: David Hess
author_rank: Super Contributor
timestamp: September 07, 2025, 05:20:44 pm
content: Quote from: tooki on August 30, 2025, 09:26:11 pmRosin flux thinners used to be about 50/50 isopropyl alcohol and toluene (I still have a bunch), but toluene is not nearly as available as it used to be. Toluene though is probably as bad as acetone for attacking plastics and marking though. The various electronics companies sell plastic and marking safe spray flux cleaner which works great, and might be the thing for a finishing rinse, but not as inexpensively as brake cleaner.QuoteI will have to try that.QuoteFor spot cleaning I have been using just acetone.It is worth mentioning that acetone is miscible with water, so also mixes well with water containing alcohols. It is also relatively non-toxic compared to some of the alternatives, like toluene.

author: artvandalai
author_rank: Regular Contributor
timestamp: September 07, 2025, 06:08:53 pm
content: Quote from: tooki on August 30, 2025, 09:26:11 pmContact cleaner isnt supposed to be used to clean flux? Ive been using the wd40 electronics contact cleaner. What ratio of alcohol to hydro carbon?

author: jpanhalt
author_rank: Super Contributor
timestamp: September 07, 2025, 06:56:36 pm
content: It's hard for me to see the purose of the hydrocarbon* if acetone is added. Both remove oils. I used absolute ethanol (before switching to ZEP) as it is also a great solvent for oils and fats. I also have lots of it from work. 95% ethanol, as most people use, is not as good. "Denatured" alcohol used to be ethanol, but that was decades ago. Today, it can be mostly methanol, which is nowhere nearly as good. There are dozens of recipes for denatured alcohol, and it requires a bit of research to find out what really is in the stuff you buy. One clue to it not being ethanol is when it is "for fuel." If it is for dissolving shellac, then it is more likely ethanol.*Acetone is not a hydrocarbon. I used about 25% to 75% acetone:absolute ethanol before switching. One trial with ZEP converted me forever, except for spot cleaning.

author: sparkyinak
author_rank: Contributor
timestamp: September 07, 2025, 10:11:55 pm
content: Thanx everyone! I've been out of the loop since posting. A lot of great resources. I need to comb through. I attached the solder's content label to add to the debate.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 07, 2025, 10:31:10 pm
content: That looks like plumbing solder flux, not electronics solder flux. Check its SDS. If it has any amount of chloride (e.g., ZnCl2) don't use it. Show us the front label.

author: Ian.M
author_rank: Super Contributor
timestamp: September 07, 2025, 11:51:58 pm
content: No need to check the SDS, its right there on the label! That's the plumber's *BAD* stuff, containing acid chlorides (both Zinc chloride and Ammonium chloride) so anything electronic you've soldered with it is a ticking timebomb waiting to die as its tracks, fine wires, and component leads are eaten away by chloride corrosion, 'the gift that keeps on giving'! See:https://en.wikipedia.org/wiki/Bronze_diseaseIt also 'eats' soldering iron tips . . .There's little hope of saving them as it will have wicked under components, and up stranded wires and once its started corroding it just doesn't stop even if you succeed in washing away all flux residue, as the chloride corrosion products are themselves corrosive in the presence of atmospheric humidity and CO2.Plumbing parts survive because the joints don't have features that trap the flux residue and the parts are much much thicker, so the same rate of corrosion that can destroy traces and fine wires in months or a year or two can be slow enough for parts to last a literal lifetime.

author: sparkyinak
author_rank: Contributor
timestamp: September 08, 2025, 02:42:35 am
content: Unfortunately, It was the only flux I could get locally. It works fine and rates for copper. I'd don't say not to use it on electrical or electronics like some solders do. I did some research before had and didn't see anything discouraging from using this type of Flux

author: Ian.M
author_rank: Super Contributor
timestamp: September 08, 2025, 03:07:38 am
content: Any flux that contains Zinc chloride or Ammonium chloride or mineral acids is an acid flux unsuitable for general electrical and electronics use. There are some specialist applications that need such a flux to tin difficult metals of substantial thickness, but it is important to immediately and thoroughly clean off all flux residue before making wire joints to the tinned area with minimally corrosive acid and chloride free electronics grade flux.Water based organic acid electronics fluxes are slightly less troublesome but still are unsuitable for hobbyist use, prototyping, and repair work due to the general lack in nearly all workshops of the specialist high-pressure jet board wash machines used on production lines to remove their residue thoroughly enough to reach the desired reliability target. Even a fly-speck stuck in a via or under a SMD part will eventually cause failure.The risk of damage from, and poor reliability of solder joints made with acid and/or chloride containing fluxes have been well known in the electrical and electronics trades, and by keener hobbyists for well over 100 years.Today is a good day as you are one of theTen Thousand!

author: Psi
author_rank: Super Contributor
timestamp: September 08, 2025, 03:49:14 am
content: Yeah, using acid-flux to clean metal for electronics soldering is like trying to have a shower with turpentine instead of water.It will clean your skin, but it's definitely not good for you.IPA will work fine for cleaning normal flux off PCBs, disadvantage is that it saturates with IPA quite fast. That means any IPA left on your PCB will re-deposit the flux back on as it evaporates.To make IPA work well you need to:- Use two separate IPA wash baths/tubs.The first is where you scrub and to get most of the flux off the board. This can be older IPA as it doesnt matter much.The second bath is clean IPA to wash off the dirty IPA. This is important if you want the PCB to look clean and streak free.(When this IPA stops working as well you just move that IPA to the other bath and get new stuff.)- A compressed air system, or similar, where you can blow all the wet IPA off the PCBbeforeit evaporates. (This avoids it re-depositing IPA back onto the PCB.)You don't need a huge amount of IPA, when i say 'bath' i just mean enough in a tub to clean/scrub the PCB, and enough in the 2nd bath to rinse it off.Make sure you are safe with regard to fumes and nearby sparks/flames, since IPA fumes are quite flammable.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 04:15:36 am
content: Your flag shows USA. Walmart and Home Depot both show electrical solder with free shipping. I didn't check Lowes. Amazon also has it.You also need to get solder. Based on the only flux you could find, what did you buy for solder? If it was plain solder for plumbing, it will be difficult to use. If it was flux core for plumbing (aka acid core), it is not the right type.Since you are in the US, you can use leaded solder for electronics and non-plumbing related things. I suggest you get a rosin core, leaded solder -- either 60:40 or 63:37 percentage of tin to lead, respectively. I prefer 63:37, others prefer 60:40.

author: Berni
author_rank: Super Contributor
timestamp: September 08, 2025, 05:57:17 am
content: Quote from: sparkyinak on September 08, 2025, 02:42:35 amYou usually don't need to use flux at all.All modern solder wire comes with a tiny amount of flux already inside of it (sort of like the solder wire actually being a very thick walled tube of metal with the middle inside filled with flux). So as you are soldering with it the flux is being added automatically, this is why one should not apply solder to the iron and carry it to the PCB joint, the solder wire must be applied directly to the hot PCB joint so that as it melts the flux inside is released onto the PCB exactly where it is needed.This makes for much less of a mess on your PCB, but it is usually a good idea to clean it off anyway.For cleaning the flux anything that has a lot of IPA in it will work. A good mix is IPA+Ethanol, works better than each of those on their own. Just remember to get it off the PCB before it evaporates (paper towel or compressed air)

author: eliocor
author_rank: Unknown
timestamp: September 08, 2025, 06:43:59 am
content: I second@Ian.M:Quote

author: BH3XON
author_rank: Contributor
timestamp: September 08, 2025, 08:23:11 am
content: Quote from: Ian.M on September 07, 2025, 12:04:19 pmWhen brushing, brush in one direction to minimize residue, then wipe with a flannel cloth to absorb any remaining liquid, and it will be almost as clean as new!

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 11:14:17 am
content: @sparkyinakI finally checked your profile and noticed your location as Ketchikan, AK.* I have only visited Alaska oonce and that was the Anchorage area. I can understand the problem you had accessing electronic solder and apologize for assuming you were in the contiguous states.Walmart is there, but its electronic solder doesn't describe critical details, like composition and flux. One offering says 60%lead 40% tin. That could be an error. The usual electronic alloy with those numbers is 60:40 tin:lead. Amazon does deliver, but with extended delivery times. I have no idea of its costs, but I suspect it is the better choice, particularly if it offers free returns.Walmart may actually have it in the DIY area and the packaging should give better info than its site gives. I assume you went to the famous Tongass Trading store. It may actually have it, but you'll need to check the labels now that you know what to look for.Finally, DigiKey (based in Minnesota) is a well known electronics supplier that originally was hobbyist focused. Today it is much larger. Mouser (based in Texas) is another option. Your cost at either might be higher as shipping is extra, but despite that, I get almost everything electronic from one of those companies.*That's 3 times the size of my nearest town, but I'm in Ohio, which makes a difference.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2025, 11:28:07 am
content: Quote from: sparkyinak on September 08, 2025, 02:42:35 amJust because a bottle of clothes dye doesn’t say “DO NOT USE AS FOOD COLORING” doesn’t mean it’s safe to do so — even if another brand does apply such a warning.Using this kind of flux for electronics is asking for disaster down the line. It’s too corrosive. (It’s fine on copper pipes and roof flashing because those are thick, and can tolerate some corrosion, and because they aren’t used with electricity, causing electromigration facilitated by the chloride ions.)

author: Ian.M
author_rank: Super Contributor
timestamp: September 08, 2025, 11:46:14 am
content: Even lump rosin pounded to a powder and dissolved in alcohol (preferably dry IPA, but 95% Everclear, or >95% denatured alcohol will do) will be a better electronics flux than that plumber's corrosion in a tub masquerading as 'general purpose' flux!

author: David Hess
author_rank: Super Contributor
timestamp: September 08, 2025, 12:48:52 pm
content: Quote from: Ian.M on September 08, 2025, 11:46:14 amRelatively clean rosin can be purchased from a music store. (1) I wonder what it would take to make it mildly or fully activated rosin for soldering purposes.(1) I have a block I bought from a music store for use on mechanical tuning indicators to prevent the line or cord from slipping.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 01:50:31 pm
content: I played with making DIY flux a couple of years ago and described it here (post #42):https://www.eevblog.com/forum/repair/restoring-dried-solder-flux-paste/msg3484434/#msg3484434I suspect viscosity can be adjusted with beeswax in addition to petroleum jelly. Kester 44 originally contained a little bromide. Current MSDS/SDS sheets do not show that. My Kester 44 flux dates from the 20th century.Here's what Google said about getting archived SDS sheets for it:Quote

author: Ian.M
author_rank: Super Contributor
timestamp: September 08, 2025, 02:18:37 pm
content: Quote from: David Hess on September 08, 2025, 12:48:52 pmRosin is also used to remove hairs from pig skin before roasting, and to make Rosin baked potatoes so is available in bulk from various online suppliers, which is likely to be cheaper and purer than music shop rosin, which is often adulterated with other substances.Hmmm . . . Of the known commercial activators, citric acid is the most readily available to the hobbyist. Its soluble in Ethanol and reasonably soluble in IPA, so I'd be inclined to try a low concentration e.g. 1% and hope the rosin doesn't precipitate it out. YMMV

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 02:48:48 pm
content: Ascorbic acid (Vitamin C) is a good reducing agent. That's also readily available and might help clean. Acetic acid (118°C) might boil too low. Other short chain organic acids have bad odors. Above C6 they aren't so bad. I've seen some mention of using benzoic acid.

author: paulca
author_rank: Super Contributor
timestamp: September 08, 2025, 03:05:24 pm
content: Does anyone have recommendations on what to use which is better than "paper towel"?I find paper towel leaves lots of unsightly paper fibres over the board.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 03:24:18 pm
content: When I use non-aqueous solvents, I don't use a paper towel at all. I cleaned and blew off the liquid before it dried.About 2 rinses in relatively fresh remover after the first (i.e., 3 total in separate jars) is what it took to get a shiny, non-sticky board. The 3rd jar gets moved to the second and so forth, so almost fresh solvent was in the third jar. I use a large , plastic trash can with liner (Home Depot HDX 55-gallon clear barrel liner) for my backdrop when blowing the solvent off.

author: Berni
author_rank: Super Contributor
timestamp: September 08, 2025, 05:03:17 pm
content: Quote from: paulca on September 08, 2025, 03:05:24 pmCompressed airTho not everyone has it at hand, tho i suppose a can of air duster or one of those handheld electric blowers could also work if it can make enough pressure. Those are particularly useful for getting the dirty solvent out from under BGAs or connectors.But paper towels is something everyone has at home. More of a use for those is to fold the towel around the board and press tightly to soak up the solvent. Doesn't get everything but it soaks up the majority of it before it can dry up and deposit the flux again. But wiping motions across the board will definelty tear it up and leave small pieces of it everywhere. You can get lint free towels thoFor smaller jobs i also like to tear off a tiny piece of towel, roll it into a ball, grab it in tweezers, dose it in IPA and then rub the alcohol soaked ball around the tiny SMD chip i just reworked. This avoids spreading the flux from a small area onto a larger one where it is more of a cleanup job.

author: NE666
author_rank: Frequent Contributor
timestamp: September 08, 2025, 05:53:23 pm
content: I think the 'best' paper towel is the one that you don't use. Which is why, as I mentioned in an earlier posting, I like to rinse well with IPA and blow-dry with compressed air (or a can, if I'm not in my workshop).I've seen clean room duster sheets use to good effect by some YT posters, which are as you would expect, lint free. However, whenever I've looked into buying them they seem to be a relatively expensive consumable, at least for hobby use.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 06:04:00 pm
content: Be aware that most air dusters sold in the US (maybe elsewhere too) contain a bitternat (denatonium is common) that is ionic and will leave a haze. I use compressed air made on site. One might also consider a nitrogen cylinder, but that could be quite expensive.I found "Gust" (dustwithgust.com) by Stoner in PA is bitterant free and works on electronics and cameras for dusting. Is is also reasonably priced compared to Walmart, etc.

author: David Hess
author_rank: Super Contributor
timestamp: September 08, 2025, 06:46:47 pm
content: Quote from: jpanhalt on September 08, 2025, 06:04:00 pmAir dusters for industry usually leave the bitterant out, but check the details.In my experience denatured alcohol from the hardware store leaves a residue, but consumer grade isopropyl alcohol may also leave a residue.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2025, 06:58:14 pm
content: Quote from: jpanhalt on September 08, 2025, 06:04:00 pmWait, are you saying that the people who are addicted to duster in USA (like the famous "It's like I'm walking on sunshine" Allison from Intervention, who amazingly not only survived and recovered, but became an addiction counselor herself) are also tolerating mouthfuls of Bitrex? Jeebus...As someone who is very sensitive to bitter, I can't even imagine.Thank goodness I have unlimited shop air (and deionized water on tap) at work!

author: Traceless
author_rank: Frequent Contributor
timestamp: September 08, 2025, 07:01:52 pm
content: Quote from: paulca on September 08, 2025, 03:05:24 pmHey paulca there are various alternatives, here some of my favourite solutionsAs mentioned before you can use cleanroom wipes.They don't have to be that expensiveand they don't leave that many fibers. Environmentally its not that great because they are one time use only.Alternatively if you have an old cotton T-shirt or sth. cut it to rags and use those for cleaning (don't use polyester because that might melt when the PCB is still hot). Get some sort of container (e.g. a lunchbox or food storage container) to store the used rags. Once the container is full throw them in the ultrasonic with a bit of dishwashing soap or laundry detergent, then dry them for reuse.You can actually use paper towel without leaving many fibers. Apply your cleaning agent, for instance IPA, and a brush to loosen all the flux. Make sure that the board is actually wet, then put the paper towel on top - don't wipe but tap it with the brush to pick up the solvent with the flux, once the towel is saturated lift it off, repeat if necessary.A new way I saw which IDON'Trecommend arethose little cleaning sponges. I'm not 100% sure what they are made off but I assume those are just little "magic eraser (aka. malamine foam) cubes". Apparently they work pretty well for cleaning flux residue. However I recentlyread an articleabout magic erasers (sorry it's in german, but browser auto translate might work) that points out that they actually containformaldehydewhich normally should be bound in the foam. However it seems that melamine can break down at pretty low temperatures, (about 71°C/160°F I believe). You can easily reach those temperatures on a preheated PCB. I'm not a chemist so I don't know how fast that foam breaks down and which substances are released in which quantities, but better safe than sorry so I just stay away from those.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2025, 07:06:53 pm
content: Quote from: Traceless on September 08, 2025, 07:01:52 pmFrom the videos I've seen of people using them, they look much too soft and resilient (bounce back) to be melamine foam, since melamine foam tends to not recover once compressed. I can't rule it out, but I very much doubt that's what they're made of.

author: Traceless
author_rank: Frequent Contributor
timestamp: September 08, 2025, 07:39:46 pm
content: Hey tooki,yeah as mentioned I haven't used them and I don't know first hand what they are made off. It's just they look suspiciously like magic eraser andsome listingseven literally state that those were melamin cleaning sponges. It may be possible that different brands use other materials though.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 08, 2025, 07:45:14 pm
content: @tooki,My understanding is that bitterants were added in response to such idiots and social media crazies. Before that, it was glue sniffers so they added mustard oil and other stuff. In America today at Walmart, you get carded to buy a duster for any solvent based glue. That's the same as for buying whiskey and is absurd. I've been building model airplanes since before I went to kindergarten and buying glue for them. Although I found the smell appealing, I never abused it -- why waste it when I needed it for my airplane?

author: David Hess
author_rank: Super Contributor
timestamp: September 08, 2025, 09:03:57 pm
content: Quote from: paulca on September 08, 2025, 03:05:24 pmThere are various lint-free tissues which are a great improvement:https://www.amazon.com/gp/product/B07NNN19DMI remember having Kimwipes at work but they were pretty harsh:https://www.amazon.com/Kimberly-Clark-34155-Kimwipes-Delicate-Tissue/dp/B075L9ZTPBI have heard that bamboo tissue is good but have not tried it yet.

author: tooki
author_rank: Super Contributor
timestamp: September 09, 2025, 06:24:59 pm
content: Quote from: Traceless on September 08, 2025, 07:39:46 pmInteresting. But the machine-translated, keyword-stuffing word salad they throw in the listing titles is of... moderate credibility. It could be melamine, but it could be just cut and pasted from other white sponges. Who knows. :/

author: tooki
author_rank: Super Contributor
timestamp: September 09, 2025, 06:43:19 pm
content: Quote from: artvandalai on September 07, 2025, 06:08:53 pmNo, of course not. Contact cleaner is for cleaning… electrical contacts. That is, the contacting parts of connectors and switches.Solder joints aren’t contacts.Anyway, because of what they’re intended for, contact cleaners are designed to remove oxides and carbon deposits from contacts. They’re not even remotely designed for flux removal.As for the ratios of alcohols to hydrocarbons in flux cleaners, I don’t know for certain off the top of my head since I don’t mix my own hydrocarbon-based flux cleaners. (I just buy them ready to use.) The MSDSs of commercial cleaners should give you a good idea. I think it’s a relatively small percentage of hydrocarbons.

author: David Hess
author_rank: Super Contributor
timestamp: September 09, 2025, 10:39:29 pm
content: The MSDS for the Chemtronics stuff we used says roughly 20% ethanol, 10% isopropyl, and 3% hexane, with the rest being inert.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 09, 2025, 11:22:41 pm
content: What's "inert" mean? Hexane is pretty inert.

author: David Hess
author_rank: Super Contributor
timestamp: September 10, 2025, 12:33:59 am
content: Quote from: jpanhalt on September 09, 2025, 11:22:41 pmIt means they do not have to list the remaining parts of the ingredients because they present no hazard.*shrug*

author: themadhippy
author_rank: Super Contributor
timestamp: September 10, 2025, 01:06:40 am
content: Quoteif yer really desperate try your local dance school,especially if they do ballet. The twirlys use it tobugger up the stage floorstop there shoes slipping

author: eliocor
author_rank: Unknown
timestamp: September 11, 2025, 12:12:58 am
content: the contents of ZEP are:Chemical name CAS-No. Concentration %2-butoxyethanol 111-76-2 >= 10 - < 202-aminoethanol 141-43-5 >= 5 - < 10The nearest product I have found (readily available here in Italy) is LAVOR Sprayer (but more diluited):https://www.tecnomat.it/it/detergente-univers-lavor-tanica-2-l-10037605/Chemical name CAS-No. Concentration %2-butoxyethanol 111-76-2 >= 1 - < 5CAPRYLETH-9 CARBOXYLIC ACID 53563-70-5 >= 1 - < 52-aminoethanol 141-43-5 >=.1 - < 1other contenders (but not easily available here in Italy) are:1.Solvent Stripper– Faber Chimica (waiting for SDS)2.Super Strip Wax Stripper– Crown Chemical3.Carefree Stripper– DiverseyP.S.: I have excluded from my search those containing acetone

author: jpanhalt
author_rank: Super Contributor
timestamp: September 11, 2025, 05:37:20 am
content: @eliocorI am not familiar with any of those cleaners. Based on the SDS or what I could find, here are my comments relative to ZEP:Lavor is similar, but less concentrated. Its capryleth-9 carboxylic acid is a non-foaming surfactant. That's sparingly soluble in water, but with butoxy ethanol and ethanol amine that should not be a problem. It probably does not leave a film and might work at a 1:2 dilution or neat.Solvent Stripper cautions about using with water. I would not use it.Super Stripper (Crown) is quite similar to Zep. It has a higher concentration of saponifier (ethanolamine). The added isopropyl alcohol probably doesn't have much effect, particularly when diluted in water. You might get by using it at a higher dilution than ZEP. I have not seen it on the shelves in the US, but that could be because I haven't looked for it.Diversey (Johnsons) is similar to Lavor. It is more dilute, and has a surfactant.Of those 4 options, if you want an aqueous product, I would not use the solvent stripper. Of the remaining 3, SuperStipper would be my first choice as it is most similar and can probably be used at a higher dilution than ZEP works at. Diversey and Lavor are similar and more dilute, but I would probably rank Diversey higher than Lavor. Of course, that is just a guess. I have not used any of them.For a first run, I would make the decision based on cost per 100 ml of working dilution. Super stripper at 1:4 or more (final volume) and the other at 1:2 (final volume). The more dilute relative to final butoxyethanol and ethanolamine concentration, the better. They can be pretty aggressive when neat and if pads/contacts are nickel/gold (ENIG) you may see some loss of the gold flash.All of these comments are based on using an ultrasonic for just 1 to 2 minutes. Of you use soaking and brushing, the times many be different.

author: Ian.M
author_rank: Super Contributor
timestamp: September 11, 2025, 09:18:26 am
content: Got another candidate:Easy StripFast Acting Floor Polish Stripper - Evans Vanodine2-BUTOXYETHANOL 15-20%2-AMINOETHANOL 5-10%1-AMINOPROPAN-2-OL 3-5%TETRA SODIUM ETHYLENE DIAMINE TETRA ACETATE 1-3%ALCOHOL (C9-11) ETHOXYLATE (8EO) 0.1-1%SODIUM (C12-14) ALKYL ETHOXY SULPHATE 0.1-1%

author: geralds
author_rank: Contributor
timestamp: September 11, 2025, 10:24:36 am
content: I once had to remove some home-made flux (rosin + IPA), that was very sticky. I used Schuelke antifect N, which worked perfectly. Ingredients: 24,75 g Ethanol (94 %), 35 g Propan-1-ol (https://www.schuelke.com/intl-en/products/P-910481/). Haven't tried it on PCBs though.

author: CatNinja
author_rank: Newbie
timestamp: September 11, 2025, 09:51:57 pm
content: If you don’t have compressed air, try a camera bulb dust blower or a nasal aspirator.

author: MathWizard
author_rank: Super Contributor
timestamp: September 16, 2025, 05:02:45 pm
content: Sometimes I've used warm or hot soapy water and a tooth brush to scrub protoboards I've made, and stuff I've repaired. The foaming action really helps, just scrap away excess flux 1st. I rinse it well then dry it by the furnace. And maybe clean with IPA after.Lately I've just been cleaning stuff with cotton swabs and IPA again, but yeah, you really need a lot, and bottles for final rinsing.RA flux can leave a lot of conductive residue sometimes. I've used scented dishsoap, so that probably not good for any sensitive parts like voltage references, etc.I should get some laboratory glass cleaner, I think that's ok for electronics too, and not full of fillers and scents, or oils, etc.Someday I'll probably get Ultrasonic cleaner, and just use it for the most sensitive stuff.