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Using Arduino => General Electronics => Topic started by: mmcp42 on Feb 08, 2013, 10:18 am

Title: what the flux?
Post by: mmcp42 on Feb 08, 2013, 10:18 am
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
Title: Re: what the flux?
Post by: tack on Feb 08, 2013, 10:32 am
http://lmgtfy.com/?q=remove+flux+after+soldering
Title: Re: what the flux?
Post by: mmcp42 on Feb 08, 2013, 11:08 am
:)
Title: Re: what the flux?
Post by: Riva on Feb 08, 2013, 12:29 pm
I use IPA solvent. http://cpc.farnell.com/pro-power/ppc103/ipa-cleaning-solvent/dp/SA01884?in_merch=Featured%20Products (http://cpc.farnell.com/pro-power/ppc103/ipa-cleaning-solvent/dp/SA01884?in_merch=Featured%20Products)
Title: Re: what the flux?
Post by: hmarrero on Feb 08, 2013, 04:27 pm
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
Title: Re: what the flux?
Post by: retrolefty on Feb 08, 2013, 05:31 pm

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
Title: Re: what the flux?
Post by: rvasque on Feb 08, 2013, 05:37 pm
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. 
Title: Re: what the flux?
Post by: mmcp42 on Feb 08, 2013, 06:19 pm
thanks for all the feedback
will give some a try :)
Title: Re: what the flux?
Post by: MarkT on Feb 08, 2013, 06:27 pm
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!)
Title: Re: what the flux?
Post by: Docedison on Feb 08, 2013, 06:27 pm
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
Title: Re: what the flux?
Post by: JoeN on Feb 08, 2013, 06:47 pm
(http://arduino.cc/forum/index.php?action=dlattach;topic=147659.0;attach=35615)

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

(http://arduino.cc/forum/index.php?action=dlattach;topic=147659.0;attach=35621)
Title: Re: what the flux?
Post by: JChristensen on Feb 08, 2013, 11:42 pm
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.
Title: Re: what the flux?
Post by: MarkT on Feb 10, 2013, 02:31 pm
Any chlorinated solvent should be used with plenty of ventilation...  Or avoided(!)
Title: Re: what the flux?
Post by: JChristensen on Feb 10, 2013, 05:42 pm
We like to say, "Better living through Chemistry!"  :D
Title: Re: what the flux?
Post by: dc42 on Feb 10, 2013, 05:49 pm
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.
Title: Re: what the flux?
Post by: mmcp42 on Feb 10, 2013, 08:28 pm

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.


not using flux per se
just using solder paste off eBay

product: XG-500
Alloy: Sn63 Pb37
microns: 25-45 uM
silent on flux content
Title: Re: what the flux?
Post by: dc42 on Feb 10, 2013, 08:44 pm
Maybe it's the solder paste? I use this no-clean paste: http://uk.farnell.com/jsp/search/productdetail.jsp?sku=876768 (http://uk.farnell.com/jsp/search/productdetail.jsp?sku=876768). I store it in a sealed bag in the fridge, and warm it before use.
Title: Re: what the flux?
Post by: mmcp42 on Feb 10, 2013, 09:20 pm

Maybe it's the solder paste? I use this no-clean paste: http://uk.farnell.com/jsp/search/productdetail.jsp?sku=876768 (http://uk.farnell.com/jsp/search/productdetail.jsp?sku=876768). I store it in a sealed bag in the fridge, and warm it before use.


thanks
I'll give that a whirl on the next project
cheers
Mike