Anyone clean their stompbox circuit boards?

[patricks]

I came across this when looking at some videos on Alice microphones, the author scrubs their boards to get rid of flux, saying that residues can lead to electrical interference (scrub with dish soap, then rinse with distilled water or isopropyl alcohol).

Anyone do this for stompboxes? Would it factor into noise, interference, or oscillation issues in higher gain circuits?

[davent]

I found wiping with alcohol made a bigger mess than what was there. I'd use a dental pick to pop off any flux from large joints to pots, jacks and the like but that was about aesthetics

[GGBB]

At 5:59: "The solder I'm using has water based flux"

Maybe that's why it can cause the problems stated?

I always clean mine with alcohol which is a bit tricky - just for looks/cleanliness. Apparently lacquer thinner works better but needs more caution around components, plastics, etc. Acetone works well too but again can damage other things.

[patricks]

Cool, thanks both!
Good thought about water-based flux.
I'm using 60/40 rosin core solder, still working through a very large roll I've had since university days, so that's not going to be a factor here

I am thinking of building a few of these mics, though, they look nice and simple and cheap for what seems like good results (got to listen on better headphones than my crummy work softphone headset)

[Focalized]

Make sure they're seasoned well before baking.

[patricks]

Make sure they're seasoned well before baking.

[Rob Strand]

I came across this when looking at some videos on Alice microphones, the author scrubs their boards to get rid of flux, saying that residues can lead to electrical interference (scrub with dish soap, then rinse with distilled water or isopropyl alcohol).

The important feature of that circuit is the 1G input impedance.   If you want 1G you need to have a clean PCB.

Most medical devices I worked on, even prototypes, have the PCB cleaned with isopropyl alcohol but often only in the rework area.

At home I don't bother unless I think it's going to corrode or I want low leakage.   If you clean with tap water the salt/ionic residues can screw things up, especially when the humidity rises.

99% of fuzz pedals will not see any increase in noise (or interference) with uncleaned PCBs.

[amptramp]

I came across this when looking at some videos on Alice microphones, the author scrubs their boards to get rid of flux, saying that residues can lead to electrical interference (scrub with dish soap, then rinse with distilled water or isopropyl alcohol).

The important feature of that circuit is the 1G input impedance.   If you want 1G you need to have a clean PCB.

Most medical devices I worked on, even prototypes, have the PCB cleaned with isopropyl alcohol but often only in the rework area.

At home I don't bother unless I think it's going to corrode or I want low leakage.   If you clean with tap water the salt/ionic residues can screw things up, especially when the humidity rises.

99% of fuzz pedal will not see any increase in noise (or interference) with uncleaned PCBs.

We always cleaned military and spacecraft boards with trichloroethylene or trichloroethane but you had to get it while the board was still warm from soldering.  It did clean up stuff and make it easier to inspect but except for the 25 megohm transresistance amplifiers used in infrared sensors, it would not make any difference in circuit operation.  What flux removal did do was enable the board to be conformally coated so humidity would be kept out.

[Mark Hammer]

There can be a great many reasons why my builds don't work right away, but I generally clean the solder side of the board with a toothbrush and some methyl hydrate.  Flux itself isn't a problem, and its not that the board has to be "clean" to work, but flux has a way of making unintended solder bridges hard to see.  If one etches one's own boards, that can be a particular concern.  So, for me at least, cleaning the board allows me to check those off the list as "It's not that".

[duck_arse]

get your hands on some Freon [no, I don't know what number]. make sure the window is open when you use it.

[PRR]

some Freon [no, I don't know what number].

It matters. R-12 was great PCB cleaner but is now quasi-banned. R-134 is a Freon but won't clean PCBs as well. R-290 (propane) has come into favor in chillers but won't clean things.

But that microphone is VERY different from almost any other audio. As Rob says, you can't have 1 Gig and theoretical cap-amp hiss after handling everyday materials. That's like 100 times higher than a parasitic resistance which would trouble any other audio amplifier. Echo Ron and Mark: inspectability and sealing. We never seem to need to seal guitar-work, and this forum is evidence that inspection may be casual, yet things often work.

[ElectricDruid]

Nope, I never clean guitar or synth PCBs.

Occasionally I might scrape a bit of something off if I see something that looks a bit suspicious when I'm inspecting the board, but I never do any sort of washing process. It's just not necessary.

[tootsMcgee]

There can be a great many reasons why my builds don't work right away, but I generally clean the solder side of the board with a toothbrush and some methyl hydrate.  Flux itself isn't a problem, and its not that the board has to be "clean" to work, but flux has a way of making unintended solder bridges hard to see.  If one etches one's own boards, that can be a particular concern.  So, for me at least, cleaning the board allows me to check those off the list as "It's not that".

This is one of two reasons I clean my boards, the other being that I like the look of clean boards

Kester claims 186 does not need to be cleaned but I do it anyway with isopropyl. I've been thinking of trying some actual flux remover products but I don't make nearly enough volume to justify the money for the time savings.

It does leave a haze if you're not super liberal about rinsing with more isopyopyl, but it gets it most of the way there with not a lot of effort.

[mark2]

With "no clean" flux, which as others pointed out is different than stuff in the video, I only clean it when I GOB it on. e.g. for SMD I'll use a liberal amount of "no clean" gel type flux in a syringe, and it makes a big sticky mess.

So I'll soak it in alcohol and blast it away with a compressor. 1-3 times.

On that note,

I found wiping with alcohol made a bigger mess than what was there.

<- compressed air, if you're able to have a compressor nearby, is awesome for getting all the contaminated liquid off the board and avoiding residue.

[amptramp]

This does bring up the question of conformal coating.  It must be used if you are using lead-free solder because lead suppresses tin whisker growth but there is nothing in lead-free solder to prevent whisker growth.  This can only be counteracted by conformal coating if lead is absent.

[Mark Hammer]

I'll reiterate that I like to clean the flux off my board because I etch and drill my own.  If one's builds are confined to professionally-made boards that have been etched, drilled and legended somewhere else, one may have considerably less need to clean the flux off, since you know there is less risk of solder bridges or unetched bridges.

[Kevin Mitchell]

It really all depends on the flux. Most of them are not water soluble and/or don't clean up well with IPA.
I had switched over to water clean Kester 331 this year so I could clean my boards in the kitchen sink - after testing my tap of course. It is suggested that it will cause corrosion if left without cleaning.
Totally worth it IMO