How do you remove flux residue after soldering?

[stan cooper]

cleaning flux residue

I agree with member ( DANGUS) using acetone or nail polish remover,or anything with a high achohol content can possibly damage other components on pc board. soaking in achohol is a definite NO- NO. if there are a lot of other parts on board, (small variable resistors etc)
I have repaired almost every guitar amp and power amp that is
advailable . when replacing transistors or other parts I think it is
a CRIME to leave FLUX RESIDUE in the area that you repaired, along with fingerprints all over the nice shinny surface of the case
and cover. ISOPROPYL ACHOHOL (~90%) is ok, along with a small surface instrument to clip out the problem areas.
Also I will give another tip about using compressed air to clean out chassis and cases with a BOX FAN. don't try to see how fast you can made the fan go. and I know I am not the only one that has heard that high pitch sound, with loud crashing noise as the
blades spreaded out and comes to a sudden stop.

hope this helps some.

stan
🙂

 

[Juergen Knoop]

I have used that water based pcb cleaning 'safewash/saferinse' combination some years ago.
Not cheap, but those circuits had to be absolutely clean.
Usually I do not clean boards after soldering, cause my solder does not leave very much or corrosive residues.
For removing a mess, qtip/toothbrush + isopropyl works for me.
regards

 

[john curl]

Polystyrene will dissolve with ANYTHING, but alcohol or FREON. Be careful!

 

[JohanB]

About potentiometers, I've succesfully used Isopropanol (Isoprophyl Alcohol) all my years for cleaning everything in electronics, even for cleaning clogged potentiometers in old radios and amplifiers. Use a lot and try to spray inside the pots. Then suck dry with an old vacuum cleaner. None explosion yet True!!
Then ofcourse relube the pots with a very short spray of "contact lubricant"

🙂 JohanB

 

[MJL21193]

Lacquer thinner and toothbrush...

Yes, it will be not so kind to the plastic tux on caps SO clean the solder side (assuming one-sided board), not the whole thing. A little on a toothbrush will cut through the grunge and make it sparling clean:

For general cleaning I've used automotive brake cleaner spray which is relatively cheap and easy to get. This doesn't seem to damage anything and cleans up old pots very well.

 

[Iain McNeill]

<OT on>
John,
the sudden change in your visage makes me think you've been spending too much time leaning over your PCB's while applying volatile hydrocarbons😀 That's quite a facelift!

But that board - those are the On Semi thermal tracks aren't they?!? Looks like you're a couple of months ahead of me. Care to share? Mebbe a new thread?

Like, why is the diode on the leftmost tranny not hooked up? What's your thermal compensation scheme? etcetc
<OT off>

 

[MJL21193]

Mebbe a new thread?

Hi Ian,
Thread is here.

 

[Peter Daniel]

I use Varsol: it cleans nicely and doesn't damage anything, wash it off under running water with some soap, then dry it off using compressed air.

AFAIK Varsol is not readily available in States.

 

[sivan_and]

Cleaning with Tooth brush dipped in petrol..that was OK for me...."diying" for 25 yrs

 

[Rikkert1978]

Alcohol you can buy from your local drugstore, and a hard brush, is what I use.
This also does not dissolve any part of the pcb, and gets dry really nice.

 

[amp_guy]

Water soluble flux has always been the best way for me.
Wash under running Water and dry with compessed air Like Peter Daniel say's
boards come out spotless

 

[titoman]

I'm changing out some SOIC surface mount opamps on a I/O for my recording setup. I'm having a problem with a mess of flux surrounding everything I unsoldered installed the new part and resoldered. How do I remove the flux?

I've heard flux residue can cause hiss in low signal sections of amps. I do not want hiss.

Forgive me if this is a dumb quesiton. I honestly haven't found any good/safe way to remove flux residue.

thanks!
Nick

use isoprophilic alcohol !

 

[Andrew Eckhardt]

Bathroom cleaner (foamy kind works great) or simple green and a toothbrush gets rid of anything water soluble or not. Rinse with water and air dry for spotless boards.

 

[Johnny2Bad]

I use Varsol: it cleans nicely and doesn't damage anything, wash it off under running water with some soap, then dry it off using compressed air.

AFAIK Varsol is not readily available in States.

It's readily available everywhere on Earth. Varsol is Esso-branded 100% pure Kerosene (Esso is Exxon Canada).

 

[magnu]

Chemtronics have some very good products. You just spray it on the board and the flux disappears

 

[destroyer X]

Kerozene (aviation fuel) and Varsol do the job

A brush will help.

regards,

Carlos

 

[TC Goh]

I use isopropyl alcohol with a tooth brush and a small paint brush for those difficult to reach areas. However, as the alcohol evaporates, condensate forms on the board, well at least here in Hong Kong where the humidity is high.

So ... after a through alcohol brush, I put it under the tap for about a minute. Then I take a hair dryer to it for about 5 – 10 mins until it is perfectly dry…

Not sure how running water will affect some sensitive components but no problems with my boards, so far. One thing is for sure, my boards are spotless!!

I tried those expensive flux cleaners that give off an awful smell but they don't do as good a job and they leave a sticky layer after.

Of course, this will only work for water resistant parts....

Regards

TC

 

[destroyer X]

Alcohol left some white thing ..some dust over the board when it dries

Kerozene..the aviation fuel (Varsol) is better.

regards,

Carlos

 

[TC Goh]

Kerozene. The variety we get here from hardware shops leave an oily film. I guess you can wash that off too.. ha ha. May be the cheapest alternative yet..

Regards

TC

 

[Marra]

Try Safewash 2000 and Saferinse 2000 from RS they work well for me.