Author Topic: Suggestions for lint-free cleaning PCB.  (Read 825 times)

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Offline Humanoid

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Suggestions for lint-free cleaning PCB.
« on: April 28, 2021, 01:59:10 am »
If I have to use Q-tips on the bottom of a PCB again, I think I'll go insane. What are you guys using to clean the snaggy bottoms of your boards?

A brush and IPA definitely clean the worst parts, and qtip is okay for soaking up the sticky parts that need it, but I need a fast easy way to clean off all the thin residue left behind on the entire board without snagging on everything.

I tried Kimtech wipes in the past but found them to be linty instead of lint-free.

 

Offline Jwillis

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Re: Suggestions for lint-free cleaning PCB.
« Reply #1 on: April 28, 2021, 03:18:19 am »
Get yourself an ESD safe cleaning brush.  Probably your best bet .  I've been meaning to get some myself  but I have been getting away with poly paint brushes for the time being .  I do a final alcohol rinse with an ordinary paint brush  and let air dry .   Probably not the best idea but I've been lucky so far .
 

Offline Doctorandus_P

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Re: Suggestions for lint-free cleaning PCB.
« Reply #2 on: May 03, 2021, 03:49:19 pm »
I usually tie my PCB's to a piece of string after cleaning and use centrifugal force to get the cleaning fluids and the dissolved stuff of before letting it dry on a warm place, often on top of my PC monitor
 

Offline tkamiya

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Re: Suggestions for lint-free cleaning PCB.
« Reply #3 on: May 03, 2021, 04:30:26 pm »
I use Q-tips VERY saturated with IPA 99.9% to get most of gunk out.  Then final rinse with new tooth brush.  Forced air to dry.  Seems to mostly work well. 
 

Offline bobbydazzler

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Re: Suggestions for lint-free cleaning PCB.
« Reply #4 on: May 03, 2021, 05:46:18 pm »
What flux do you use?  Try water soluble.
 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #5 on: May 04, 2021, 12:13:34 am »
What flux do you use?  Try water soluble.

I only have a tube of amtech at the moment.
 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #6 on: May 04, 2021, 12:14:52 am »
I use Q-tips VERY saturated with IPA 99.9% to get most of gunk out.  Then final rinse with new tooth brush.  Forced air to dry.  Seems to mostly work well.

Same (though I don't have NEW toothbrushes to use). I do clean my brushes with IPA which gets rid of old flux. However, I can never seem to get rid of all the residue. It always looks like there is a light film on the board.
 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #7 on: May 04, 2021, 12:17:35 am »
Get yourself an ESD safe cleaning brush.  Probably your best bet .  I've been meaning to get some myself  but I have been getting away with poly paint brushes for the time being .  I do a final alcohol rinse with an ordinary paint brush  and let air dry .   Probably not the best idea but I've been lucky so far .

I actually just ordered 2 brushes from digikey to try them out since I needed to get some parts.

I also found a video where they were wetting the board with IPA, then laying down a kimtech wipe, and then brushing lightly over top of the wipe with a brush to help the wipe soak up the flux. Going to give that a go once my order arrives.
 

Offline TimNJ

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Re: Suggestions for lint-free cleaning PCB.
« Reply #8 on: May 04, 2021, 01:44:29 am »
Get yourself an ESD safe cleaning brush.  Probably your best bet .  I've been meaning to get some myself  but I have been getting away with poly paint brushes for the time being .  I do a final alcohol rinse with an ordinary paint brush  and let air dry .   Probably not the best idea but I've been lucky so far .

I actually just ordered 2 brushes from digikey to try them out since I needed to get some parts.

I also found a video where they were wetting the board with IPA, then laying down a kimtech wipe, and then brushing lightly over top of the wipe with a brush to help the wipe soak up the flux. Going to give that a go once my order arrives.

Kimwipes are my go to. No issues with lint. As you already hinted at, key is not really move the Kimwipe too much. Lay it flat on the board, dip a horse-hair (or similar) brush in IPA, then kind of blot the board through the wipe. The stiff horse hair brush has worked well for me. I sort of vigorously vibrate the brush with my hand to loosen the flux, which then gets wicked up into the wipe, as you suggested.
 
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Offline TimNJ

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Re: Suggestions for lint-free cleaning PCB.
« Reply #9 on: May 04, 2021, 01:52:31 am »
I’ve used the soft bristle acid brushes, paint brushes, tooth brushes, etc. and have found this one to be sooo much better than all of those.

https://www.digikey.com/short/wfbc24z2
 
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Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #10 on: May 04, 2021, 03:45:36 am »
Kimwipes are my go to. No issues with lint. As you already hinted at, key is not really move the Kimwipe too much. Lay it flat on the board, dip a horse-hair (or similar) brush in IPA, then kind of blot the board through the wipe. The stiff horse hair brush has worked well for me. I sort of vigorously vibrate the brush with my hand to loosen the flux, which then gets wicked up into the wipe, as you suggested.

I’ve used the soft bristle acid brushes, paint brushes, tooth brushes, etc. and have found this one to be sooo much better than all of those.

https://www.digikey.com/short/wfbc24z2

Thanks for the tips. Yeah, I didn't realize they were being used that way with a brush so they were getting snagged or creating lint from rubbing on components.

I was going to order that same brush you listed, but I opted to go for 2 cheaper ones since I didn't know what to expect and thought it might be too stiff, both horse hair though. They both have conductive metal handles and I have a ground strap for my mat, so figured that was best. One looked stiffer with black bristles and the other was softer and tan with more bristles.
 

Offline TimNJ

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Re: Suggestions for lint-free cleaning PCB.
« Reply #11 on: May 04, 2021, 01:15:45 pm »
Kimwipes are my go to. No issues with lint. As you already hinted at, key is not really move the Kimwipe too much. Lay it flat on the board, dip a horse-hair (or similar) brush in IPA, then kind of blot the board through the wipe. The stiff horse hair brush has worked well for me. I sort of vigorously vibrate the brush with my hand to loosen the flux, which then gets wicked up into the wipe, as you suggested.

I’ve used the soft bristle acid brushes, paint brushes, tooth brushes, etc. and have found this one to be sooo much better than all of those.

https://www.digikey.com/short/wfbc24z2

Thanks for the tips. Yeah, I didn't realize they were being used that way with a brush so they were getting snagged or creating lint from rubbing on components.

I was going to order that same brush you listed, but I opted to go for 2 cheaper ones since I didn't know what to expect and thought it might be too stiff, both horse hair though. They both have conductive metal handles and I have a ground strap for my mat, so figured that was best. One looked stiffer with black bristles and the other was softer and tan with more bristles.

I’m sure you’ll be fine. In my experience, stiffer bristles do a better job dislodging flux, especially when the brush is being used to “blot” or “swirl” instead of “wipe”. Also in my experience, the tan bristle brushes are stiffer than black, but maybe not for the ones you bought. As I said, I think you’ll be fine.  :)
 
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Offline PerranOak

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Re: Suggestions for lint-free cleaning PCB.
« Reply #12 on: May 04, 2021, 04:48:24 pm »
Best lint-free cloth is a cut-up old work shirt.

Well, assuming you worked in an office! You know, the thin cotton collared ones.
« Last Edit: May 04, 2021, 04:50:00 pm by PerranOak »
Some light can never be seen!
RJD
 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #13 on: May 04, 2021, 10:16:06 pm »
I’m sure you’ll be fine. In my experience, stiffer bristles do a better job dislodging flux, especially when the brush is being used to “blot” or “swirl” instead of “wipe”. Also in my experience, the tan bristle brushes are stiffer than black, but maybe not for the ones you bought. As I said, I think you’ll be fine.  :)

These are the ones I ordered:

https://www.digikey.com/product-detail/en/mg-chemicals/855-5/473-1048-ND/949490

https://www.digikey.com/product-detail/en/techspray/2033-1/1873-1085-ND/7914549

I will find out in a few days when they arrive :)

Dislodging the thick patches of flux works fine with a toothbrush, but it tends to create a film that the IPA and qtips don't grab all of it. It's more about getting the residue all off the board. Hopefully the kimtechs + brush soak up that leftover crap so I can get on with my life.

Thanks for the help
 

Offline JustMeHere

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Re: Suggestions for lint-free cleaning PCB.
« Reply #14 on: May 05, 2021, 12:04:33 am »
I use the PCB safe flux cleaner from MG Chemicals.   Scrub it with an old toothbrush.  Then hit it again with the flux cleaner to "rinse" it.   

The key is to rinse it.  Spraying it on there without enough cleaner to make it drip off just doesn't wash the flux off of the board.
 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #15 on: May 07, 2021, 08:41:10 pm »
I’m sure you’ll be fine. In my experience, stiffer bristles do a better job dislodging flux, especially when the brush is being used to “blot” or “swirl” instead of “wipe”. Also in my experience, the tan bristle brushes are stiffer than black, but maybe not for the ones you bought. As I said, I think you’ll be fine.  :)

The brushes arrived. You were correct—the stiffer of the two is the tan bristle. Works better than a toothbrush.

I only used it once so far, but I find that it soaks up a lot of flux. Cleaning it in a small amount of IPA helps flush the bristles.

Am experimenting with the kimtech wipes for final residue removal. Seems to take several passes on an area to get the flux off. Not sure if dabbing or circular motions is proving more effective yet, but they stand up well to the horse hair regardless.
 

Offline Skashkash

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Re: Suggestions for lint-free cleaning PCB.
« Reply #16 on: May 07, 2021, 09:10:34 pm »
I also use Kimtech wipes to blot up the flux residue after brushing.  I mostly use IPA as a flux solvent these days (with some additives). 

 But I also use forced air as an air knife to blow off the flux remover and flux residue. Find this works better for me.

Highly recommend the Metrovac dusters. Great if you don't have a compressor in the shop.
https://www.amazon.com/dp/B00U01YVYK/ref=cm_sw_em_r_mt_dp_2RKD34EXXCNA8295Y1AG   
 

 

Offline Humanoid

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Re: Suggestions for lint-free cleaning PCB.
« Reply #17 on: May 07, 2021, 10:14:12 pm »
I also use Kimtech wipes to blot up the flux residue after brushing.  I mostly use IPA as a flux solvent these days (with some additives). 

 But I also use forced air as an air knife to blow off the flux remover and flux residue. Find this works better for me.

Highly recommend the Metrovac dusters. Great if you don't have a compressor in the shop.
https://www.amazon.com/dp/B00U01YVYK/ref=cm_sw_em_r_mt_dp_2RKD34EXXCNA8295Y1AG   

I have a similar air blower and also use IPA, but it's just straight 99% IPA. Will give it a try.  :-+
 


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