Brake cleaner is cheap and cleans PCBs really well

[duckduck]

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. 

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://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.

[ChristofferB]

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!

[BrokenYugo]

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.

[mawyatt]

Just ordered some MG Flux Remover, will have to remember this brake cleaner when the MG runs out!!

Thx for the note.

Best,

[Tomorokoshi]

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.

[M4trix]

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. 

[mawyatt]

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. 

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,

[T3sl4co1l]

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

[amyk]

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.

[mawyatt]

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,

[SteveyG]

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.   

[Gyro]

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

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.

[mawyatt]

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,

[SteveyG]

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:

[BrokenYugo]

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.

[Fraser]

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

[Gyro]

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.

[floobydust]

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 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.

[T3sl4co1l]

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

[Someone]

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.

[John B]

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.

[amyk]

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

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.

[tom66]

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.

[Monkeh]

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.

[T3sl4co1l]

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