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Topic: what the flux? (Read 1 time) previous topic - next topic

mmcp42

what is the best way to remove flux residue after soldering SMD devices
everything is working, just doesn't look very nice with muddy stains all over the boards?

cheers
Mike
there are only 10 types of people
them that understands binary
and them that doesn't

tack

http://lmgtfy.com/?q=remove+flux+after+soldering

mmcp42

there are only 10 types of people
them that understands binary
and them that doesn't

Riva

http://forum.arduino.cc/index.php?action=unread;boards=5,67,10,11,66,12,15,17,21,22,23,24,25,29;ALL

hmarrero

I have used acetone and 90% Isopropyl alcohol before with success... however you must be careful with plastics as both of these chemicals react with some plastics. It should be fine on a PC board though.

Hugo

retrolefty


what is the best way to remove flux residue after soldering SMD devices
everything is working, just doesn't look very nice with muddy stains all over the boards?

cheers
Mike


I just use water and a tooth brush, works fine with a little patience. I've found too many times that some chemicals like Isopropyl alcohol on some PCBs cause a smeary mess that's hard to clean off.

Lefty

vasquo

90% alcohol from Walgreens. ... and a toothbrush.

Before the alcohol dries, you need to dry it with a dampcloth. Otherwise, the flux that you brushed and got dissolved in alcohol, will remain on the board after the alcohol evaporates... leaving a film mess.

Sometimes it takes a second scrubbing (and helps if you also brush all the alcohol off the board, so it's taking with it all the dissolved flux)

Remember, before the alcohol evaporates, it needs to be patted down with a cloth. That's the trick for me. 

mmcp42

thanks for all the feedback
will give some a try :)
there are only 10 types of people
them that understands binary
and them that doesn't

MarkT

One plastic that is very intolerant of most solvents is polycarbonate - even the oils in citrus
peel will dissolve it!

If you are using solderpaste to solder SMT components then look for "no-clean" solder
paste - the flux evaporates I think, leaving hardly any residue.

For rosin flux a two-stage cleaning process seems to work for me - first spray on and
scrub to break up any hard lumps.  Secondly apply more solvent and allow to drain from the side of the board, this
tends to carry away most of the rosin (which will just precipitate out again if the solvent
dries in place - so do this cold to reduce evaporation (the first application tends to reduce
the board temperature nicely!)
[ I won't respond to messages, use the forum please ]

Docedison

#9
Feb 08, 2013, 06:27 pm Last Edit: Feb 08, 2013, 06:33 pm by Docedison Reason: 1
If you use a water soluble flux cleaning is easy. 1. Lather, 2. rise, 3. Repeat...
If not and you use a solvent containing water (AKA Alcohol) you must wait until or dry the PCB first, A heat gun works very well.
{Edit RKJ}
AS MarkT pointed out above orange oil is the best solvent for that purpose.


Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

JoeN

#10
Feb 08, 2013, 06:47 pm Last Edit: Feb 08, 2013, 06:52 pm by JoeN Reason: 1


Plus a toothbrush, or if you want to be really cool:

I have only come here seeking knowledge. Things they would not teach me of in college.

Jack Christensen

Denatured ethanol or tetrachloroethylene, a toothbrush, and an air compressor. Brake cleaner (Brakleen brand in the red can, not the green can) is tetrachloroethylene, and works well. Best used outdoors.
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

MarkT

Any chlorinated solvent should be used with plenty of ventilation...  Or avoided(!)
[ I won't respond to messages, use the forum please ]

Jack Christensen

We like to say, "Better living through Chemistry!"  :D
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

dc42

I don't now why you are getting muddy stains. What flux are you using? For SMD soldering I use a no-clean flux pen and solder paste, and I don't see any flux residues.
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