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  #1  
Old 04-09-2011, 02:57 AM
bob332 bob332 is offline
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Default Cleaning Question - White residue after cleaning...

i have noticed after cleaning boards w/ 91% ISP that there is a white residue on the components and slight haze on the board. my process is to clean the board before hand w/ 91% ISP, not handle components by any leads and most of the time i am placing them by tweezers as they are smd (qfn, tqfp, 0402, 0603, etc) and to only touch the board on the sides, not near any contacts. to clean, i use a new toothbrush, pour the ISP on the new toothbrush and then go over the solder joints. the boards work excellent, and i have no electrical issue w/ the soldering technique and am always trying to refine it to get it better, but this cleaning is bothering me. guess i get a little anal about my projects...

i use this solder:

http://www.mouser.com/Search/Product...y590-4894-227G

&

http://parts.digikey.com/1/parts/955...-smd291ax.html

any way i can have a clean board w/ no white residue/haze would be greatly appreciated, and hopefully w/ easily accessible household/drugstore items

thanks,
bob

edit - the board needs to be dry after the cleaning as it will be exposed and not 'sealed up' at all, but not rain, just outdoor weather that one would be in flying radio controlled models around the globe

Last edited by bob332; 04-09-2011 at 05:19 AM.
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Old 04-09-2011, 05:10 AM
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Try Spraying contact cleaner..it works for me...get's rid of that white haze stuff and leaves a protective yet dust collecting oily layer.

This is what I get here.
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Old 04-09-2011, 05:17 AM
bob332 bob332 is offline
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man, i should have mentioned the board needs to be dry as it will be exposed and not sealed up. not rain, but weather you would expect when flying radio controlled models around the globe.
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Old 04-09-2011, 05:21 AM
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Then get Plastic coating type of spray.
It will insulate from dust and humidity.

Clean the board with Acetone, let it dry and then spray a protective coating.

Sgt mentioned it to me...Conformal Coating or something
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Old 04-09-2011, 07:25 AM
bob332 bob332 is offline
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will acetone take of the silkscreen info?

appreciate the info
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Old 04-09-2011, 07:56 AM
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Nope..Acetone just cleans, it's harmless....but stay away from it's vapor

I use Acetone in a Paint spray gun. Pretty easy to wash Motherboards but it does not deal with the type of flux I have.
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Old 04-09-2011, 08:15 AM
bob332 bob332 is offline
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thanks, will give it a try. any issue going over the boards i cleaned w/ ISP? just want to make sure no ill effects would strike my boards.
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Old 04-09-2011, 08:43 AM
jpanhalt jpanhalt is offline
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Caution: acetone is not harmless. It will melt or soften many different plastics, including polystyrenes, acrylics, PVC, and ABS. It way also affect the printing on the board. It will cause most enamel paints to crinkle or be removed. Acetone is a major component in many paint removers.

I use absolute ethanol to clean my boards. Isopropyl alcohol (IPA) which is what you used also works well. Water in your IPA may cause the incomplete removal of excess flux. Or, if the board had a solder mask on it, the milky residue may be from slightly dissolving that masking material. As the IPA evaporates, it leaves behind a little water, which may be what is causing the coating to become a little milky, like when a cold drink is set on a lacquered surface. A little bit of water can make a huge difference in the solvent properties of alcohols, including IPA and ethanol.

My suggestions:
1) If the IPA was fresh and truly 91%, I would either just leave the residue or try water to remove it. After water, re-rinsing with IPA will help dry it.
2) The residue is probably harmless.
3) If you coat with a conformal coating to protect from moisture, the slight haziness will probably disappear. Commercial conformal coatings are essentially clear, acrylic lacquers. Some have a dye added for color.

John
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Old 04-09-2011, 08:52 AM
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John....not to disagree but. What you say does not happen, ever since you mentioned Acetone, I went and bought it and I use High pressure to spray and wash away dirt.
It does a pretty good job, It haven't obviously damaged any of my boards. If it had I would not recommend it.

I use it instead of thinner cause it does not leave any residue.

Or could it be that what I get here is not actually Acetone?
and one more thing, our Thinner is more powerful than the Acetone I bought.
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Old 04-09-2011, 09:04 AM
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Quote:
Originally Posted by bob332 View Post
i have noticed after cleaning boards w/ 91% ISP that there is a white residue on the components and slight haze on the board.
you could use 100% isp, that should not have any residue.
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