EEVblog Electronics Community Forum

General => General Technical Chat => Topic started by: duckduck on July 21, 2021, 10:29:18 pm

Title: Brake cleaner is cheap and cleans PCBs really well
Post by: duckduck on July 21, 2021, 10:29:18 pm
Late to the party, but I'm now privvy to the dirty little secret: brake cleaner works great for cleaning PCBs and is cheap as chips (USD6 for 822 grams). I'm using CRC Brakleen Pro-Series Brake Parts Cleaner which is mainly trichloroethylene. Chlorinated hydrocarbons are famous for being toxic to the liver and central and peripheral nervous systems, depleting the ozone layer, contributing to global warming, causing liver and kidney cancers, and being great degreasers. I was cleaning up a used bass guitar amplifier last night. I got it for cheap because it was having issues with intermittent noise in the output. The PCBs had 15-year-old flux on them which easily wiped away with a Q-tip soaked with Brakleen. It didn't damage the lettering or soldermask. At an absolute minimum, I would recommend going outdoors and wearing safety glasses if you are going to use this vile chemical. I'm probably going to throw on my VOC respirator and put on gloves, too. Between the Brakleen, some Deoxit, and a little elbow grease, the amp is now noise free -- depending on your opinion of hard rock/funk/metal bass.  ;D

In the USA brake cleaner is also sold in non-chlorinated flavors. From decades of experience working on cars (as an avocation), I feel comfortable saying that it doesn't work worth a flip for degreasing. Check the label before you buy. My local Wal-Mart has stopped selling brake cleaner (and CRC-brand electronics cleaner, which does an amazing job of cleaning motorcycle plastics without damaging them). Not sure if they are gaining a conscience or (more likely) someone in corporate ran the numbers and there isn't enough money in it to justify the liabilities of shipping/stocking/selling such dangerous chemicals.

EDIT:

I learned about brake cleaner for PCB cleaning from YouTuber SDG Electronics.

EDIT EDIT:

https://en.wikipedia.org/wiki/Trichloroethylene (https://en.wikipedia.org/wiki/Trichloroethylene)
https://www.epa.gov/sites/default/files/2016-09/documents/trichloroethylene.pdf (https://www.epa.gov/sites/default/files/2016-09/documents/trichloroethylene.pdf)

EDIT EDIT EDIT:

Cleaned up phrasing a little. I have tried IPA and even, as recommended by YouTuber Mr. Carlson, paint thinner. The IPA leaves white residue and the paint thinner takes a (relatively) long time to evaporate. I will have to try out some proper flux cleaner.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: ChristofferB on July 21, 2021, 11:17:08 pm
Toxicity aside (and I believe there are worse chlorinated solvents - they're all lousy for humans) - one thing to be careful with about chlorinated solvents is their tendency to make polymers and rubbers 'swell' - this might affect components and certain PCB substrates too.

Ultrasonicating high pressure o-rings in dichloromethane is common practice in my lab, but occasionally, depending on the composition you end up with an o-ring 1.5x the original size!

Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: BrokenYugo on July 21, 2021, 11:28:00 pm
Gotta watch the label, some of the non chloro is all petroleum based and supposedly works well, but a lot of it is mostly acetone. Probably the same story with the carburetor cleaners.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: mawyatt on July 21, 2021, 11:35:40 pm
Just ordered some MG Flux Remover, will have to remember this brake cleaner when the MG runs out!!

Thx for the note.

Best,
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Tomorokoshi on July 22, 2021, 12:03:56 am
For basic cleaning CRC QD Electronic Cleaner is safe on plastics.

CRC Brakleen Brake Parts Cleaner is okay, but test on plastics first.

Ironically, CRC Lectra-Motive Electric Parts Cleaner is the most likely to damage plastics.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: M4trix on July 22, 2021, 12:39:31 am
Chlorinated hydrocarbons are famous for being toxic to the liver and central and peripheral nervous systems, depleting the ozone layer, contributing to global warming, causing liver and kidney cancers, and being great degreasers.

mmmm.... I'm happy with my IPA.  :phew:
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: mawyatt on July 22, 2021, 12:52:43 am
Chlorinated hydrocarbons are famous for being toxic to the liver and central and peripheral nervous systems, depleting the ozone layer, contributing to global warming, causing liver and kidney cancers, and being great degreasers.

mmmm.... I'm happy will my IPA.  :phew:

Me too, but isn't alcohol also toxic to the liver, especially if ingested in large quantities  ::)

Some of those IPAs are pretty tasty too :-+

Best,
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 22, 2021, 04:27:48 am
You joke, but isopropyl alcohol is just metabolized to acetone, which then is largely excreted through breathing.  As I understand it, it's a shitty buzz... but surprisingly not very toxic, on par with ethanol.

So, while I wouldn't suggest making a cocktail with acetone or isopropyl; it is true that ethanol is suitable for cleaning, if you happen to have it in a reasonably pure form (Everclear for the drinkable kind, or denatured whatever if not).

Acetone and MEK are often okay for electronics as well, but as with all of these, BE CAREFUL AND CHECK FIRST.  A lot of inks and plastics soften, swell or dissolve in the more aggressive (more aliphatic, or aromatic for that matter) solvents.  Electrolytics may be compromised by exposure.

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: amyk on July 22, 2021, 04:36:56 am
Gotta watch the label, some of the non chloro is all petroleum based and supposedly works well, but a lot of it is mostly acetone. Probably the same story with the carburetor cleaners.
The non-chlorinated ones are the ones with "flammable" warnings. I believe a lot of them use hexane/heptane or a mixture of hydrocarbons around there (more volatile than gasoline.) The chlorinated ones are marketed as "non-flammable", and at least to me, have a much more pleasant smell - but unfortunately are also more toxic.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: mawyatt on July 22, 2021, 12:30:11 pm
You joke, but isopropyl alcohol is just metabolized to acetone, which then is largely excreted through breathing.  As I understand it, it's a shitty buzz... but surprisingly not very toxic, on par with ethanol.

So, while I wouldn't suggest making a cocktail with acetone or isopropyl; it is true that ethanol is suitable for cleaning, if you happen to have it in a reasonably pure form (Everclear for the drinkable kind, or denatured whatever if not).

Acetone and MEK are often okay for electronics as well, but as with all of these, BE CAREFUL AND CHECK FIRST.  A lot of inks and plastics soften, swell or dissolve in the more aggressive (more aliphatic, or aromatic for that matter) solvents.  Electrolytics may be compromised by exposure.

Tim

IPA is India Pale Ale and high alcohol content and somewhat bitter tasting beer  ;)

Best,
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: SteveyG on July 22, 2021, 03:41:47 pm
Brake Cleaner is one of those you need to read the label on, most are fairly mild these days but they should not affect plastics and rubber. There's too many plastic and rubber parts in modern braking systems so the formulation (aside from health/environmental reasons) has changed.

All of the ones from Eurocarparts (not a sponsor) are suitable, but don't mix it up with carb cleaner. Carb cleaner will happily eat through many plastics and polymers, especially black and white solder resist.   
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Gyro on July 22, 2021, 04:15:16 pm
I thought the Chlorinated ones were banned these days. :-\

Just in case people aren't aware, aside from the general toxicity at room temperature, they decompose to Phosgene gas when heated above 315'C. That's in soldering iron territory!

There have been well documented cases of people doing welding on vehicles, where residues of Chlorinated brake cleaner have been present, seriously gassing themselves, eg. https://www.brewracingframes.com/safety-alert-brake-cleaner--phosgene-gas.html (https://www.brewracingframes.com/safety-alert-brake-cleaner--phosgene-gas.html)

It would be really easy for residues of liquid brake cleaner to still be lurking under IC packages when you get the iron out to touch up a joint.

Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: mawyatt on July 22, 2021, 05:04:27 pm
That's nasty stuff, same as Mustard Gas I recall. My grandfather was gassed in WWI with Mustard, and remember reading in Europe where people still get hands burned when digging. The gas from WWI seeped into the ground and still remains!!

Thanks for the alert!!

Best,
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: SteveyG on July 22, 2021, 05:15:57 pm
I thought the Chlorinated ones were banned these days. :-\

Certainly banned from sale in the EU. I can't speak for our American friends


Also worth pointing out that most car parts vendors will sell it in 5 litre containers. I'd recommend this format as the aerosols dispense surprisingly quickly, too fast for benchtop use.

Video for those that missed it, Eric O even dropped a comment:
https://www.youtube.com/watch?v=d3Qmm6Tegb4 (https://www.youtube.com/watch?v=d3Qmm6Tegb4)
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: BrokenYugo on July 22, 2021, 05:55:00 pm
I suspect you only hear about accidental phosgene (which is not mustard gas) in welding because a powerful electric arc is about the only place you'll get intense enough heat to break the solvent down to any notable degree before it boils away. IIRC the old CFCs used in board cleaning can do the same thing, but they apparently didn't.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Fraser on July 22, 2021, 05:58:28 pm
StevetG,

Thanks for the video. Very interesting as I have mainly used IPA for flux cleaning but will get some suitable brake cleaner to try.

Loved your homage sound effect to Eric O  :) I am also a fan of his excellent channel  :-+

Fraser
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Gyro on July 22, 2021, 06:34:30 pm
I suspect you only hear about accidental phosgene (which is not mustard gas) in welding because a powerful electric arc is about the only place you'll get intense enough heat to break the solvent down to any notable degree before it boils away. IIRC the old CFCs used in board cleaning can do the same thing, but they apparently didn't.

Hard to know, the critical temperature is apparently 315'C so I don't know what would happen if you stuck an iron tip at say, 350'C in a little puddle of it (don't think I want to find out). Phosgene was originally synthesized from a mixture of Carbon Monoxide and Chlorine and a bit of sunshine (presumably whatever UV and Blue spectrum that made it through the flask). I don't know if that gives any idea of what sort of energy input is needed, I think they use an activated carbon catalyst these days but no idea about temperatures.

I remember, donkeys years ago when I was at school, they suddenly got very jumpy about Carbon Tetrachloride in the chemistry labs. The lab techs would put buckets of Ammonia around the lab whenever it was being used near sources of heat (Ammonia being about the only thing that neutralises Phosgene in the air). I don't know if it worked, but the smell of those classes was certainly memorable!

Carbon Tetrachloride was of course used in fire extinguishers at one time! I found one is a junk shop just a couple of month ago which still swished when I shook it. Probably quite a rare occurrence - I remember my Dad telling me that during his national service, their main use was for getting grease stains out of uniforms, so they were almost invariably empty when needed!

I never liked organic chemistry. I was hopeless at it too. :D
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: floobydust on July 22, 2021, 07:46:00 pm
IPA works fine, just let it soak in a bowl and it works really well. People don't have patience and resort to harsh chemicals.

Brake cleaner is a terrible chemical soup, changed many times over the years. Do your homework and read the MSDS.
Brakleen Brake Parts Cleaner (https://rwsidley.com/MSDS/crc%20brakleen.pdf) is 80-90% acetone and 1-3% toluene.

Years ago I worked in a shop that used it and one welder got the reaction fumes and taken to hospital. It was quite bad and a big puzzle to figure out how he generated the toxic fumes from his arc. They banned the use of Brakleen after that. It used to be highly carcinogenic.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 22, 2021, 08:47:23 pm
You joke, but

IPA is India Pale Ale and high alcohol content and somewhat bitter tasting beer  ;)

Yes.... I acknowledged that joke.  Perhaps not specifically enough... :)

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Someone on July 23, 2021, 12:11:27 am
Also worth pointing out that most car parts vendors will sell it in 5 litre containers. I'd recommend this format as the aerosols dispense surprisingly quickly, too fast for benchtop use.
Once you're buying 5l can/bottles of flux cleaner the price is low enough that it'd be hard to suggest anything else (cheap compared to the possible damage/rework). Still check the MSDS, many flux cleaners are nasty to biological systems as in humans/rabbits/fish etc.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: John B on July 23, 2021, 01:40:03 am
If I was to substitute automotive cleaners for electronics use - and I probably wouldn't - mass airflow sensor cleaner may be a safer choice. They are designed to be sprayed on electronic components and plastic.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: amyk on July 23, 2021, 04:37:28 am
I thought the Chlorinated ones were banned these days. :-\

Just in case people aren't aware, aside from the general toxicity at room temperature, they decompose to Phosgene gas when heated above 315'C. That's in soldering iron territory!

There have been well documented cases of people doing welding on vehicles, where residues of Chlorinated brake cleaner have been present, seriously gassing themselves, eg. https://www.brewracingframes.com/safety-alert-brake-cleaner--phosgene-gas.html (https://www.brewracingframes.com/safety-alert-brake-cleaner--phosgene-gas.html)

It would be really easy for residues of liquid brake cleaner to still be lurking under IC packages when you get the iron out to touch up a joint.
For a very long time, a "leak detector torch" was used to detect CFC refrigerants - essentially noticing the change of colour of a flame to show that it was present. They always came with warnings not to breathe the products of combustion, but I wonder how many got poisoned by it. You might still find old refrigeration techs using them today...

Most chlorinated solvents are volatile enough that not much will be left after a short time at normal room temperature. In fact, that's why they're used.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: tom66 on July 23, 2021, 06:44:54 pm
To be honest Fluxclene from Electrolube isn't expensive (9.70 GBP ex tax for 400ml in an aerosol) - a bit more than brake cleaner but absolutely safe on every PCB component I've used and very effective at making a PCB look 'brand new' even after rework.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Monkeh on July 23, 2021, 06:56:33 pm
To be honest Fluxclene from Electrolube isn't expensive (9.70 GBP ex tax for 400ml in an aerosol) - a bit more than brake cleaner but absolutely safe on every PCB component I've used and very effective at making a PCB look 'brand new' even after rework.

You have a strange definition of not expensive for a blend of cyclohexane, isopropanol, and heptane. Electrolube are laughing to the bank with that stuff. Oh, there's a bit of antifreeze in it too.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 23, 2021, 08:58:46 pm
If you're not buying them by the barrel, plus it's packed in an aerosol can, I fail to see how that's at all atypical retail markup.

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Monkeh on July 23, 2021, 09:10:30 pm
If you're not buying them by the barrel, plus it's packed in an aerosol can, I fail to see how that's at all atypical retail markup.

Tim

I buy 600ml cans of brake cleaner for £2.50 or so.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 23, 2021, 09:41:44 pm
That's pretty good. I get a liter of acetone around here for like $10.  Haven't looked at brake cleaner in a while...

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: tom66 on July 23, 2021, 10:03:11 pm
You have a strange definition of not expensive for a blend of cyclohexane, isopropanol, and heptane. Electrolube are laughing to the bank with that stuff. Oh, there's a bit of antifreeze in it too.

I bought two cans about two years ago and I'm about half-way through the first.  I think I'll manage with paying the retail markup.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: MathWizard on July 24, 2021, 11:02:55 am
On the little PCBs I've been working on this year, I've just been using hot soapy water, and a toothbrush. Then I just dry them over my computers fans. It seems to work pretty well, but some stuff I really don't like getting wet.

I've been using some strong MG flux, and it leaves conductive residue sometimes, I should not use it on SMD anymore.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 24, 2021, 10:48:31 pm
Interesting. I don't know that I've used any flux that would respond much at all to soapy water, even after a looong soak.  Strong bases though, saponify the rosin acids effectively.  But that does nothing for the metal soaps/salts already present (i.e. the cruddy stuff that the rosin did its job at dissolving).  So it'll still leave crud, plus being rather aggressive towards anything else present (may degrade plastics?).

Heh, or you're using so much rosin that the base chemicals (usually some combination of petroleum jelly and glycol ethers?) stick around (the deposit is still gooey?), and the metal oxides are well dissolved and dispersed, not clumpy.  So everything suspends and washes away.  There's never too much flux... ;D

I would suppose a combination of base (maybe a milder one like ammonia will do? -- may complex (dissolve) some of the metal salts too) and alcohols might do the best.  Not sure what all they use in commercial blends.  (Note that acetone is incompatible with base, it'll oligomerize; alcohols are okay, as are most detergents.)

(Heh, and that's pure base by the way; carbonates, phosphates, silicates, etc. will all precipitate metal ions, no chance of them dissolving.  Probably just as good a reason as any, why base isn't as effective as I might first imagine...)

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: helius on July 25, 2021, 07:20:03 am
You joke, but isopropyl alcohol is just metabolized to acetone, which then is largely excreted through breathing.  As I understand it, it's a shitty buzz... but surprisingly not very toxic, on par with ethanol.

So, while I wouldn't suggest making a cocktail with acetone or isopropyl; it is true that ethanol is suitable for cleaning, if you happen to have it in a reasonably pure form (Everclear for the drinkable kind, or denatured whatever if not).

Acetone and MEK are often okay for electronics as well, but as with all of these, BE CAREFUL AND CHECK FIRST.  A lot of inks and plastics soften, swell or dissolve in the more aggressive (more aliphatic, or aromatic for that matter) solvents.  Electrolytics may be compromised by exposure.

Acetone is only excreted in the breath to a limited degree. It also passes into, and acidifies, the urine. The test for so-called "ketone bodies" in urine (mostly acetone) is used as a sign that fats are being metabolized.

Isopropyl alcohol is not fatal to ingest (within reasonable limits), but it causes intense colic-like abdominal pains. That is why you do not hear about people drinking it (ethanol itself is a "shitty high" compared to many alternatives).
Ingestion of elemental iodine also causes such pains.

As the subject of brake cleaners comes up with some regularity, it needs to be pointed out that the term is ambiguous. CRC Industries makes two major types of BrāKleen: 05089 is nearly pure perchloroethylene; 05088 is a mixture of methanol, toluene, and hexane. Both are powerful degreasers, but Perc is not generally plastic or rubber safe. The other products in the line are diluted with acetone to comply with local air quality laws, which is an issue because acetone is also not safe on plastic or soldermask. So while they will definitely dissolve flux residue, they are not formulated to be safe on electronics.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: BrokenYugo on July 25, 2021, 08:26:15 am
If I was to substitute automotive cleaners for electronics use - and I probably wouldn't - mass airflow sensor cleaner may be a safer choice. They are designed to be sprayed on electronic components and plastic.

CRC MAF cleaner claims to be mostly naptha*, 2-methylpentane, and some other solvents. But like I said earlier, none of these solvent soups are at all standardized, you have to do the homework.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: bson on July 25, 2021, 06:37:07 pm
Just be very careful with brake cleaners and heat.  At 315 deg C tetrachloroethylene becomes phosgene, which will kill you in relatively small concentrations.  Personally I'd never use a brake cleaner with tetrachloroethylene to clean a PCB, but I do use it to clean mechanical parts - however I personally only use it outdoors.  The reason for not using it to clean PCBs is I expose the PCBs to heat in a closed room, and while it can be argued they're dry, it has all evaporated, etc - it's not worth the risk to me.  I find it prudent to avoid the possibility of mistakes that can't be made...
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Gyro on July 25, 2021, 10:01:33 pm
Just be very careful with brake cleaners and heat.  At 315 deg C tetrachloroethylene becomes phosgene, which will kill you in relatively small concentrations.  Personally I'd never use a brake cleaner with tetrachloroethylene to clean a PCB, but I do use it to clean mechanical parts - however I personally only use it outdoors.  The reason for not using it to clean PCBs is I expose the PCBs to heat in a closed room, and while it can be argued they're dry, it has all evaporated, etc - it's not worth the risk to me.  I find it prudent to avoid the possibility of mistakes that can't be made...

Who didn't read the first page?  ;)
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: tooki on July 27, 2021, 03:46:34 pm
mmmm.... I'm happy with my IPA.  :phew:

IPA works fine, just let it soak in a bowl and it works really well. People don't have patience and resort to harsh chemicals.

The problem with isopropyl is that many modern fluxes, especially the no-clean types, are not fully alcohol-soluble. No amount of IPA will fully dissolve them, leaving behind the infamous white deposits. Ironically, cheap 70-90% rubbing alcohol may work better for these fluxes than 99% IPA, since many of those residues are water-soluble.

But commercial flux removers do a much better job, frankly, and do it in much less time. I a) can't have a bowl of IPA sitting around at work (and you'd still need a separate rinse!), b) not all components can be immersed, and c) I don't have the time to wait for things to soak. Why use navigable amounts of IPA and lots of time to achieve only an OK result, when a commercial product lets me use tiny amounts, does the job quickly, and leaves the boards squeaky clean??
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: BrokenYugo on July 27, 2021, 05:44:38 pm
mmmm.... I'm happy with my IPA.  :phew:

IPA works fine, just let it soak in a bowl and it works really well. People don't have patience and resort to harsh chemicals.

The problem with isopropyl is that many modern fluxes, especially the no-clean types, are not fully alcohol-soluble. No amount of IPA will fully dissolve them, leaving behind the infamous white deposits. Ironically, cheap 70-90% rubbing alcohol may work better for these fluxes than 99% IPA, since many of those residues are water-soluble.

But commercial flux removers do a much better job, frankly, and do it in much less time. I a) can't have a bowl of IPA sitting around at work (and you'd still need a separate rinse!), b) not all components can be immersed, and c) I don't have the time to wait for things to soak. Why use navigable amounts of IPA and lots of time to achieve only an OK result, when a commercial product lets me use tiny amounts, does the job quickly, and leaves the boards squeaky clean??

Can confirm, I've tried to clean boards every way imaginable with 91% IPA and get the white crap, I even tried a vapor chamber. The stuff seems fairly insoluble in water too, you have to scrub it off. Haven't gotten far enough to figure out if it's the old 90s Radio Shack 60/40, The MG 835 RA, or both.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: G7PSK on July 28, 2021, 02:43:57 pm
Its the UV UVc being the main culprit due to its high energy from arc welding that breaks down carbon tet. to phosgene. IPA fumes wont cause you any harm in the quantities that most are likely to encounter. The same goes for brake cleaner and carb cleaner, unless you are sloshing it around by the gallon just ensure adequete ventilation.

Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: ElektroQuark on July 28, 2021, 05:59:26 pm
FWIW, with MG Chemicals No Clean Flux Paste Cat. No. 8341 and IPA you get TONs of that white residue.  :palm:
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: tooki on July 28, 2021, 09:01:01 pm
FWIW, with MG Chemicals No Clean Flux Paste Cat. No. 8341 and IPA you get TONs of that white residue.  :palm:
Can confirm, as that’s the flux paste I have at home. As I said, very common for no-clean fluxes. But to be clear, MG does not claim it to be cleanable in IPA: they recommend “solvent systems” like [several of their flux cleaner products], so the facepalm isn’t warranted.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: rdl on July 28, 2021, 09:09:59 pm
IPA is a pretty poor solvent for most things. If it actually does work for something, then ethanol is almost always better.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: SiliconWizard on July 28, 2021, 09:27:06 pm
IPA is a pretty poor solvent for most things. If it actually does work for something, then ethanol is almost always better.

IPA is fine for cleaning... no-clean fluxes. ;D
Yes, no-clean fluxes also leaves residues, and whereas those are supposed to be harmless, I still prefer cleaning the boards.
But yeah, for other kinds of fluxes, IPA mixed in can leave an awful gunk.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Cerebus on July 28, 2021, 11:41:32 pm
Acetone and MEK are often okay for electronics as well, but as with all of these, BE CAREFUL AND CHECK FIRST. 

MEK will definitely make rubber swell, it was sold to the offset litho printing trade as "blanket restorer" specifically because it would make the rubber 'blanket' used in offset printing swell back to its originally bounciness after it had a few million impressions slammed into it by the impression cylinder. (I was an inky fingered offset litho printer for a couple of years in the dim and distant past.)
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Cerebus on July 28, 2021, 11:55:23 pm
Interesting. I don't know that I've used any flux that would respond much at all to soapy water, even after a looong soak.  Strong bases though, saponify the rosin acids effectively.  But that does nothing for the metal soaps/salts already present (i.e. the cruddy stuff that the rosin did its job at dissolving).  So it'll still leave crud, plus being rather aggressive towards anything else present (may degrade plastics?).

Heh, or you're using so much rosin that the base chemicals (usually some combination of petroleum jelly and glycol ethers?) stick around (the deposit is still gooey?), and the metal oxides are well dissolved and dispersed, not clumpy.  So everything suspends and washes away.  There's never too much flux... ;D

I would suppose a combination of base (maybe a milder one like ammonia will do? -- may complex (dissolve) some of the metal salts too) and alcohols might do the best.  Not sure what all they use in commercial blends.  (Note that acetone is incompatible with base, it'll oligomerize; alcohols are okay, as are most detergents.)

(Heh, and that's pure base by the way; carbonates, phosphates, silicates, etc. will all precipitate metal ions, no chance of them dissolving.  Probably just as good a reason as any, why base isn't as effective as I might first imagine...)

Tim

A few weeks ago, out of pure curiosity, I tried cleaning flux reside off some slightly scummy old scrap boards I had around (a bunch of small IR remote control boards that came from I remember not where) with warm dilute sodium carbonate (i.e. washing soda) solution, about the same concentration you'd use in a sink or bucket for normal domestic purposes. It did a surprisingly good job and seemed to clean everything off, including the ring of metal salts that often gets left behind by other cleaning methods. As I say, this was idle curiosity, not a proper scientific experiment but the results were encouraging.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: T3sl4co1l on July 29, 2021, 06:50:02 am
Ah, interesting!

Tim
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: tooki on July 29, 2021, 07:26:17 am
IPA is a pretty poor solvent for most things. If it actually does work for something, then ethanol is almost always better.

IPA is fine for cleaning... no-clean fluxes. ;D
Yes, no-clean fluxes also leaves residues, and whereas those are supposed to be harmless, I still prefer cleaning the boards.
But yeah, for other kinds of fluxes, IPA mixed in can leave an awful gunk.
Incorrect. It’s the no-clean fluxes that IPA is bad at removing. It works fine for most traditional rosin fluxes.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: duckduck on September 15, 2021, 04:18:31 pm
N.B.: Chlorinated brake cleaner makes (at least some) plastic parts extremely brittle. I've now got a new plastic case on the way for my Garmin GPS because I thought it would be smart to clean it with brake cleaner and it crumbled into tiny little crispy bits.  :palm:
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: amyk on September 15, 2021, 11:32:33 pm
Chlorinated solvents tend to attack plastics pretty aggressively - methylene chloride can be used for plastic welding, for example.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: helius on September 16, 2021, 01:43:50 am
As can MEK, but I find the latter easier to use as it doesn't evaporate instantly as DCM does.

DCM on the left, MEK on the right.
They both work better if a small amount of ABS is dissolved in the solvent (this is how many modeling glues are made). Using the brush cap and returning it to the bottle will carry in plastic resin slowly as well.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Halcyon on September 16, 2021, 08:25:49 am
What about a dishwasher and a bit of detergent?
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: jpanhalt on September 16, 2021, 09:31:08 am
Has anyone tried E85 "flex" fuel? 

In the US, it is at least 50% ethanol + light petroleum distillates (https://afdc.energy.gov/fuels/ethanol_e85_specs.html ).  Apparently the ethanol percentage is higher in the Summer.  In the US, it is spec'd to contain 51% to 83% ethanol.  Many of the commercial flux removers have petroleum spirits in them too.  Doesn't smell too bad either.  It is also less than $3/gal in my area.

I bought some the other day (Summer in Ohio), but haven't had a chance to use it. 
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Halcyon on September 16, 2021, 09:58:27 am
Has anyone tried E85 "flex" fuel? 

For cars it's terrible but for a cleaner,,, Hmmm maybe?
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: SteveyG on September 16, 2021, 10:27:10 am
N.B.: Chlorinated brake cleaner makes (at least some) plastic parts extremely brittle. I've now got a new plastic case on the way for my Garmin GPS because I thought it would be smart to clean it with brake cleaner and it crumbled into tiny little crispy bits.  :palm:

I doubt you can by chlorinated brake cleaner anywhere. It's removed from sale in most countries, but it's also useless given how many plastics etc are in modern braking systems.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: jpanhalt on September 16, 2021, 11:10:46 am
Last time I checked, chlorinated CRC #05089 (tetrachloroethylene) is still available in most of the US (some states and Catalina Island excepted):

http://docs.crcindustries.com/msds/1003707E.pdf (http://docs.crcindustries.com/msds/1003707E.pdf)

https://www.amazon.com/CRC-Industries-CRC05089-Brakleen-Cleaner/dp/B00JRPDW7M/ref=sr_1_8?dchild=1&gclid=EAIaIQobChMIpKSi_auD8wIVxB-tBh03GAVvEAAYAiAAEgLgnfD_BwE&hvadid=410003049532&hvdev=c&hvlocphy=1024046&hvnetw=g&hvqmt=b&hvrand=4736616961383246466&hvtargid=kwd-275822662&hydadcr=12275_11121344&keywords=brakleen&qid=1631790147&sr=8-8 (https://www.amazon.com/CRC-Industries-CRC05089-Brakleen-Cleaner/dp/B00JRPDW7M/ref=sr_1_8?dchild=1&gclid=EAIaIQobChMIpKSi_auD8wIVxB-tBh03GAVvEAAYAiAAEgLgnfD_BwE&hvadid=410003049532&hvdev=c&hvlocphy=1024046&hvnetw=g&hvqmt=b&hvrand=4736616961383246466&hvtargid=kwd-275822662&hydadcr=12275_11121344&keywords=brakleen&qid=1631790147&sr=8-8)

https://www.amazon.com/CRC-05089-BRAKLEEN-Brake-Cleaner/dp/B000LDR9HI/ref=sr_1_5?dchild=1&gclid=EAIaIQobChMIpKSi_auD8wIVxB-tBh03GAVvEAAYAiAAEgLgnfD_BwE&hvadid=410003049532&hvdev=c&hvlocphy=1024046&hvnetw=g&hvqmt=b&hvrand=4736616961383246466&hvtargid=kwd-275822662&hydadcr=12275_11121344&keywords=brakleen&qid=1631790249&sr=8-5 (https://www.amazon.com/CRC-05089-BRAKLEEN-Brake-Cleaner/dp/B000LDR9HI/ref=sr_1_5?dchild=1&gclid=EAIaIQobChMIpKSi_auD8wIVxB-tBh03GAVvEAAYAiAAEgLgnfD_BwE&hvadid=410003049532&hvdev=c&hvlocphy=1024046&hvnetw=g&hvqmt=b&hvrand=4736616961383246466&hvtargid=kwd-275822662&hydadcr=12275_11121344&keywords=brakleen&qid=1631790249&sr=8-5)

I bought several cans of it.  That said, I don't use it on PCB's.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: Cerebus on September 16, 2021, 12:23:00 pm
N.B.: Chlorinated brake cleaner makes (at least some) plastic parts extremely brittle. I've now got a new plastic case on the way for my Garmin GPS because I thought it would be smart to clean it with brake cleaner and it crumbled into tiny little crispy bits.  :palm:

I doubt you can by chlorinated brake cleaner anywhere. It's removed from sale in most countries, but it's also useless given how many plastics etc are in modern braking systems.

Where do you think all that plastic is? The only plastic I've ever seen in the bit of a braking system that one would use brake cleaner on, the calliper and disc, is the rubber in the hoses and seals (generally EPDM rubber because they have to resist hydraulic oil).
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: helius on September 16, 2021, 01:14:52 pm
Last time I checked, chlorinated CRC #05089 (tetrachloroethylene) is still available in most of the US (some states and Catalina Island excepted):
I bought several cans of it.  That said, I don't use it on PCB's.
I don't either. It does work very well for cleaning metal parts, as well as for removing stains from fabric. These operations should be done outdoors or with fume extraction.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: jpanhalt on September 16, 2021, 02:55:42 pm
I don't either. It does work very well for cleaning metal parts, as well as for removing stains from fabric. These operations should be done outdoors or with fume extraction.

You can bet it is/was good for "dry cleaning."  AKA, "PERC" (perchloroethylene).  It works well with just a little water (5% or so) and was easily recovered and reused.  Don't know if it is still used.
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: BrokenYugo on September 16, 2021, 03:47:32 pm
Has anyone tried E85 "flex" fuel? 

In the US, it is at least 50% ethanol + light petroleum distillates (https://afdc.energy.gov/fuels/ethanol_e85_specs.html ).  Apparently the ethanol percentage is higher in the Summer.  In the US, it is spec'd to contain 51% to 83% ethanol.  Many of the commercial flux removers have petroleum spirits in them too.  Doesn't smell too bad either.  It is also less than $3/gal in my area.

I bought some the other day (Summer in Ohio), but haven't had a chance to use it.

Maybe I got a bad batch or something but I cannot agree with your opinion on the smell whatsoever. The one time I had the displeasure of working on the fuel system of an E85 car a small spill stunk up the nicely air conditioned workshop so badly we opened every door and window, on a hot humid mosquito infested Michigan summer night. Real nasty rotten food sort of smell. I could only see using the stuff as a cleaner outdoors and upwind.   
Title: Re: Brake cleaner is cheap and cleans PCBs really well
Post by: SteveyG on September 16, 2021, 06:39:04 pm
Where do you think all that plastic is? The only plastic I've ever seen in the bit of a braking system that one would use brake cleaner on, the calliper and disc, is the rubber in the hoses and seals (generally EPDM rubber because they have to resist hydraulic oil).

Most pads are plastic backed to eliminate the use of grease, then you have the wear sensors, guide pin sleeves, anti squeal shims etc. There's then everything in the surrounding areas which will get sprayed during cleaning, arch liners, abs sensors, just about every other sensor...

Brake cleaner gets used for everything in an automotive workshop though, particularly cleaning oil and grease residue in the engine bay.