99 percent alcohol made pcb sticky

[Tally810]

So I just recently bought a bottle of 99 isopropyl  to clean all of my PCBs and when I cleaned the first one ito put a super sticky film on the pcb.  Anyone know why this happened and how to get it off?

[robbles]

The alcohol could have corroded the top layer of the PCB, causing it to become sticky. 99% is a really high percentage.

[digi]

Yea, that's way too high. You should use 70%.

[SixtyLife]

could also be flux that got spread over the pcb as you were cleaning.. that stuff is pretty sticky

[Joey Quinn]

could also be flux that got spread over the pcb as you were cleaning.. that stuff is pretty sticky

I think this is the answer, isopropyl shouldn't destroy a pcb, I've used 99% in the past without issues.

Are you sure you didn't use nail polish remover or something acetone based?

[Gatix]

What do you use to apply it?

Can confirm with flux being spread, happened to me lol. In my case, I used a single q tip for the whole board and ended up just spreading flux...

[chyros]

99% is for pussies.

If you've cleaned it weirdly, you might've spread the dirty stuff around rather than get it off the board. Alternatively, you might've dissolves and re-spread part of the soldermask, but it must've been rather weak stuff, because I haven't had any issue with analytical grade iPoOH so far.

[Tally810]

could also be flux that got spread over the pcb as you were cleaning.. that stuff is pretty sticky

I think this is the answer, isopropyl shouldn't destroy a pcb, I've used 99% in the past without issues.

Are you sure you didn't use nail polish remover or something acetone based?

Naw it was definatly 99 percent isopropyl but it makes sense that I spread the solder resin around making Ithe sticky.

[Tally810]

The alcohol could have corroded the top layer of the PCB, causing it to become sticky. 99% is a really high percentage.

Hmm really? I did my research and many very reputable members of the community said to only use 93 percent or higher and never lower.  Seems I didn't get all of the solder residue off and that made it sticky from what other people are telling me.

[Tally810]

99% is for pussies.

If you've cleaned it weirdly, you might've spread the dirty stuff around rather than get it off the board. Alternatively, you might've dissolves and re-spread part of the soldermask, but it must've been rather weak stuff, because I haven't had any issue with analytical grade iPoOH so far.

Well it's a new leeku pcb so I think you are right about just spreading the solder around.  What do you use usually to wipe it with?

[Tally810]

What do you use to apply it?

Can confirm with flux being spread, happened to me lol. In my case, I used a single q tip for the whole board and ended up just spreading flux...

I used a single q tip as you said lol.

[keytohopiness]

That would be like detailing your car with a single Q-tip.

[Tally810]

That would be like detailing your car with a single Q-tip.

I hear ya but it "looked" to be doing the job until I felt how sticky it was.  Then I stopped being scared that I might mess something up.

[need]

"dissolved solder mask/top layer" - haha this makes me laugh.

[Tally810]

"dissolved solder mask" - haha this makes me laugh.

Maybe on a ****ty pcb? Not on a leeku.  Seems I figured the problem tho. Thanks guys

[Photoelectric]

Yeah it's just the left-over flux getting smeared over the PCB.  Until it's mostly cleaned off, the surface is a bit sticky.

[OfTheWild]

As others have said... it is dissolved flux left on the board. Its normal but if you want to keep cleaning switch to a cotton ball or paper towel and keep wiping.

[Tally810]

Yeah it's just the left-over flux getting smeared over the PCB.  Until it's mostly cleaned off, the surface is a bit sticky.

Yea makes sense thanks I've has 4 PCBs laying around dirty and decided to finally clean them and this happened lol

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[Tally810]

Yeah it's just the left-over flux getting smeared over the PCB.  Until it's mostly cleaned off, the surface is a bit sticky.

Yea makes sense thanks I've has 4 PCBs laying around dirty and decided to finally clean them and this happened lol

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Will do that next.  Thanks

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[need]

You won't be able to clean the residue off completely with cotton buds, but people suggests rinsing under water and scrub with a toothbrush. Hair dry it and let it sit under the sun.

[Tally810]

You won't be able to clean the residue off completely with cotton buds, but people suggests rinsing under water and scrub with a toothbrush. Hair dry it and let it sit under the sun.

The pcb? I think I'll pass on that one

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[Photoelectric]

I've had pretty good results with cotton balls, just clean a few times over the same areas with fresh cotton balls.  Going in circular motion helps with reducing the amount of cotton strands being stuck in small parts.  I've tried Kim Wipes, as they were well-regarded and recommended here before, but those just ball up and leave bits of fiber on the PCB, so I prefer large cotton balls.

[Tally810]

I've had pretty good results with cotton balls, just clean a few times over the same areas with fresh cotton balls.  Going in circular motion helps with reducing the amount of cotton strands being stuck in small parts.  I've tried Kim Wipes, as they were well-regarded and recommended here before, but those just ball up and leave bits of fiber on the PCB, so I prefer large cotton balls.

Sounds good man thanks will give it a shot

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[Joey Quinn]

I've had pretty good results with cotton balls, just clean a few times over the same areas with fresh cotton balls.  Going in circular motion helps with reducing the amount of cotton strands being stuck in small parts.  I've tried Kim Wipes, as they were well-regarded and recommended here before, but those just ball up and leave bits of fiber on the PCB, so I prefer large cotton balls.

Sounds good man thanks will give it a shot

I use a toothbrush that I dip in the isopropyl to clean pcbs, it gets the job done and doesn't leave any fibers left over.

[robbles]

Rather than making a new thread, gonna hijack this one real quick. Does isopropyl work for cleaning rubber domes? Or is that something I should use warm dish soap for? Thanks.

[Joey Quinn]

Rather than making a new thread, gonna hijack this one real quick. Does isopropyl work for cleaning rubber domes? Or is that something I should use warm dish soap for? Thanks.

I think isopropyl can damage some rubbers but you'd need to soak them to have an issue, given that it can cause damage I'd say that warm water is the best answer.

[Photoelectric]

I've had pretty good results with cotton balls, just clean a few times over the same areas with fresh cotton balls.  Going in circular motion helps with reducing the amount of cotton strands being stuck in small parts.  I've tried Kim Wipes, as they were well-regarded and recommended here before, but those just ball up and leave bits of fiber on the PCB, so I prefer large cotton balls.

Sounds good man thanks will give it a shot

I use a toothbrush that I dip in the isopropyl to clean pcbs, it gets the job done and doesn't leave any fibers left over.

Doesn't the toothbrush just shift the disolved flux around the PCB and leaves a lot there, just moved around?  That's what happens when I try to use a flat toothbrush.  Cotton balls pick up the flux and keep it in the fibers.  I can see a brush being useful at the end to pick up stray fibers from cotton balls.

[Joey Quinn]

Doesn't the toothbrush just shift the disolved flux around the PCB and leaves a lot there, just moved around?  That's what happens when I try to use a flat toothbrush.  Cotton balls pick up the flux and keep it in the fibers.  I can see a brush being useful at the end to pick up stray fibers from cotton balls.

No, the toothbrush does wick away the flux, probably not as well as cotton does but it works well enough for me. In the end using a cotton ball first and doing the final pass/ clean up with a toothbrush may be the way to go.

I also have luck using trimmed paint brushes to clean around microcontrollers.

[OfTheWild]

i still just use q-tips and a fingernail... a beer and some good music. Slow but meditative. I like the toothbrush idea, i'll have to try that.

[E3E]

could also be flux that got spread over the pcb as you were cleaning.. that stuff is pretty sticky

I think this is the answer, isopropyl shouldn't destroy a pcb, I've used 99% in the past without issues.

Are you sure you didn't use nail polish remover or something acetone based?

Though I wouldn't recommend it, I've even used acetone before just to test the strength of a mask. Didn't do a thing to it. I think the masks are a sort of epoxy in most cases, and they don't react with common cleaners like alcohol or even acetone.

[jaffers]

I don't use acetone or isopropyl because they are far more expensive than methylated spiritsspirits which I have used for the past few years to clean pcb's with tooth brush. I put about 2 shot's worth in a cup and then scrub the board down thoroughly, the resin will still be in the spirits because its just a solvent, so when it flashes off it will leave the resin behind which is sticky.

You need to rinse it and give it a few passes with a toothbrush with new alcohol. Then rinse again and once its all flashed off and dried I like to give it a scrub down with a dry toothbrush to get rid of any flaky thin residue. Works a treat, do it to everything, and all the boards I build

Pack of toothbrushes is like $2 and 4L of methylated spirits is like $5

[jcoffin1981]

I use a 3/4" artist's horsehair brush.  It's stiff enough to clean and soft enough not to damage anything. I use 99% isopropyl.  Now if you spilled something gunky and your cleaning off root beer or something, the 70% alcohol will probably work better.  The water will evaporate fast enough where it will not cause a problem.

[Tally810]

I use a 3/4" artist's horsehair brush.  It's stiff enough to clean and soft enough not to damage anything. I use 99% isopropyl.  Now if you spilled something gunky and your cleaning off root beer or something, the 70% alcohol will probably work better.  The water will evaporate fast enough where it will not cause a problem.

Yea it was no spill.  I just had 4 boards laying around that had solder residue on them and was gonna spiff them up.  Once I get some time I'll try some of the suggestions I've gotten in this thread.  Thanks for the advice

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[Photoelectric]

By the way, cleaning old well-dried flux is usually noticeably more work than cleaning freshly soldered joints (within a few days of soldering). 

[Tally810]

By the way, cleaning old well-dried flux is usually noticeably more work than cleaning freshly soldered joints (within a few days of soldering).

Yea makes sense

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[OfTheWild]

By the way, cleaning old well-dried flux is usually noticeably more work than cleaning freshly soldered joints (within a few days of soldering).

Yea makes sense

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I tend to just blob on a bunch of alcohol and let it soak for a bit. Seems to work well enough.

[Wingklip]

99% is for pussies.

If you've cleaned it weirdly, you might've spread the dirty stuff around rather than get it off the board. Alternatively, you might've dissolves and re-spread part of the soldermask, but it must've been rather weak stuff, because I haven't had any issue with analytical grade iPoOH so far.

I use drain cleaner








Jk

[Tally810]

99% is for pussies.

If you've cleaned it weirdly, you might've spread the dirty stuff around rather than get it off the board. Alternatively, you might've dissolves and re-spread part of the soldermask, but it must've been rather weak stuff, because I haven't had any issue with analytical grade iPoOH so far.

I use drain cleaner








Jk

Man 4 realzg

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[Moistgun]

I don't use acetone or isopropyl because they are far more expensive than methylated spiritsspirits which I have used for the past few years to clean pcb's with tooth brush. I put about 2 shot's worth in a cup and then scrub the board down thoroughly, the resin will still be in the spirits because its just a solvent, so when it flashes off it will leave the resin behind which is sticky.

You need to rinse it and give it a few passes with a toothbrush with new alcohol. Then rinse again and once its all flashed off and dried I like to give it a scrub down with a dry toothbrush to get rid of any flaky thin residue. Works a treat, do it to everything, and all the boards I build

Pack of toothbrushes is like $2 and 4L of methylated spirits is like $5

Nice try jaffers. No one is ever gonna use denatured other than you. Lol

[digi]

I use drain cleaner
Jk

I like the way drain cleaner tastes..