PCB Clean Up

Inquisitive

Super Moderator
I use solder flux that is in a bottle and apply it with a small brush where needed when soldering. It is non-corrosive. It is Isopropyl Alcohol and Gum Rosin based. To clean up the rosin a high percentile isopropyl alcohol was used in the past. Which leads me to ask.

Does Isopropyl Alcohol remove conformal coatings on PCB's? My boards in the past have not had conformal coatings as they were handmade.

What should I use. Are there newer methods I should be looking at?

Any insight you could provide would be appreciated. Thanks for your interest and help.

3v0

Coop Build Coordinator
Forum Supporter
I tried commercial stuff but settled on dawn dish soap and a tooth brush. No I have not knocked any SMD parts loose but I don't use anything smaller the 602 or is it 603 (you know what I mean).

As to what dissolves a conformal that depends on what it is.

Inquisitive

Super Moderator
Never heard of using dish soap in that application. I'll check it out. Obviously one would have to allow ample time for the board to dry before energizing it and avoid immersing switches.

Brevor

Member
I use a small brush with denatured alcohol, followed by a mild solution of Dawn in water then a quick rinse with de ionized water. Avoid switches and transformers.

Inquisitive

Super Moderator
De-ionized water is not readily available around here. Can distilled water be used instead as it is readily available.

kinarfi

Well-Known Member
What about using reverse osmosis water, I just use denatured alcohhol and a heavy duty tooth brush type brush and air. Some times a small wire brush.

picbits

Well-Known Member
I use IPA in an ultrasonic cleaning tank and give it a couple of minutes blast after leaving to soak for a couple of minutes.

dougy83

Well-Known Member
I know of a [small scale] manufacturer that puts his boards in a dishwasher, I think he uses dishwashing powder. Apparently results are sparkling. I was a little concerned about the use of caustic on the pcbs, but from what I've heard, they work alright.

I've never had much luck with IPA and ultrasonics on my hand-soldered pcbs; the flux just stays there.

atferrari

Well-Known Member
I recall a long and detailed post by Dean Huster, former technician at Tektronix explaining in detail a cleaning process, maybe dated (or maybe not!). He evidently knew what he was talking about.

I cannot recall in what forum. Maybe at EPE. Worth the effort to find it.

ronv

Once owned an interest in an assembly house. For the first year or two we used dishwashers. Made money faster than we could spend it, so bought a $250,000 board cleaner with all the bells and whistles - out of business a couple years later. atferrari Well-Known Member Once owned an interest in an assembly house. For the first year or two we used dishwashers. Made money faster than we could spend it, so bought a$250,000 board cleaner with all the bells and whistles - out of business a couple years later.
An eventual symmetry of that process would have you currently washing dishes with it...!

ChrisP58

Well-Known Member
The cleaning method needs to match the type of flux used.

I have been using water soluble flux both in wire core and liquid form for years now. Easily cleans up with warm water or isopropyl alcohol. I have a pump bottle with IPA and a toothbrush at my bench for cleaning up hand work.

ronv

Well-Known Member
An eventual symmetry of that process would have you currently washing dishes with it...!
Funny you bring that up. I was on the note for it and trust me it wouldn't have fit in my kitchen.

atferrari

Well-Known Member
Ron, why the washing was actually needed? As part of the production process?

Brevor

Member
De-ionized water is not readily available around here. Can distilled water be used instead as it is readily available.
I think most any water is fine, I just use de ionized water because I have it available where I work. I used to use plain tap water with good results.

KeepItSimpleStupid

Well-Known Member
the OP said:
I use solder flux that is in a bottle and apply it with a small brush where needed when soldering. It is non-corrosive. It is Isopropyl Alcohol and Gum Rosin based. To clean up the rosin a high percentile isopropyl alcohol was used in the past. Which leads me to ask.

Does Isopropyl Alcohol remove conformal coatings on PCB's? My boards in the past have not had conformal coatings as they were handmade.
This thread started talking about one thing and then seemed to go off on a tangent.

I'm guessing that th OP doesn't really know what a conformal coating is or I don't.

I'm thinking the OP is talking about the removal of the soldermask. When I of a "conformal coating", I think of an overspray that's put on circuit boards to protect against the environment like moisture.

What's I'll say is that flux is best removed early. A commercial flux remover can be used. I've used Acetone and a cotton swab for spot repairs. Then I followed with methanol.

With conformal coatings mechanical means and knowing what the coating is, matters.

Inquisitive

Super Moderator
Yes, think that I was referring to solder mask and incorrectly named it. As that is how you would receive unpopulated boards from the board house.

MrAl

Well-Known Member
Hi,

Above and beyond all else what works better than anything else is of course, sandblasting. After you sandblast the board it's pretty clean (ha ha).

Ok seriously, back in the 80's Trichloroethylene was the cleaner used most often, but i dont think that is allowed anymore due to environmental and human health issues.

In the past we had used isopropyl alcohol also and it works pretty well. It's hard to find something that wont remove any protective coating. What we used to do was clean the whole board and then have it coated again. That meant a complete cleaning of any flux as well as all protective coating first, then when dry simply coat the entire board again as if it had never been coated in the first place.