PCB Cleaning?

[Spandex]

Hello Peeps,

I bought some of this "PCB & Flux Cleaner" from Maplin (http://www.maplin.co.uk/pcb-cleaner-27521) thinking it'd do exactly what it said on the tin - but instead found that it made my board look like crap.. covered in a kind of sticky residue.  Perhaps I wasn't using it right.  In the end, I went and got a toothbrush and some 99% isopropyl I had lying around and cleaned all the flux remover (and flux?) off with that.  It's pretty spangly now.

Do you think I was using the PCB cleaner wrong??  Or should I expect to have to wash it off with water or isopropyl afterwards?  Doesn't say ote on the can about that - just says I should wipe it off.  But it was more like I'd spilled something sticky on there.. wiping wasn't gonna cut it.

Wondering if, in future, I might get some "Poly Clens" - and do it as per this article http://www.100randomtasks.com/squeaky-clean-boards

Anyone else got any top tips?

Cheers,

Matt Spandex

[Roger Light]

Hi Matt,

We use flux cleaner and then a brush (cheap toothbrush is a good bet)
to give it a vigorous scrub, followed by a wipe off with a paper
towel. How much effort you have to go to depends on how much flux you
use and how thick it is, as well as how powerful the solvent is and
how much of it you use. I think the scrubbing part is useful,
particularly if you have the kind of dried flux shown in the poly
clens link you gave.

We use "no clean" flux pens like
http://uk.farnell.com/circuitworks/cw8100/dispensing-pen-no-clean-flux/dp/130692
which contain a very thin fluid flux. I'd avoid the gunky type fluxes
you get. "No clean" is a bit of a lie - they will always leave a
slight residue (but much better than the gunky ones) - but it's only a
very small amount of effort to clean off. For what it's worth, we use
this flux cleaner:
http://uk.farnell.com/electrolube/lffr400db/flux-remover-lead-free-400ml/dp/1098276

I'd say it's maybe a minute or two to clean them.

If you're using external flux (ie. not just in the solder), it's
possible you're using more flux than is necessary, which will mean you
have more to clean up. I've seen it suggested that "you can never use
too much flux" but I disagree. It's best to keep your flux usage to a
minimum - only use what you need and don't assume that everything
needs flux. I mostly only use flux on fine pitch ICs or if I'm having
trouble with something.

Cheers,

Roger

[jfowkes]

I've never had a problem with isopropyl, or the little bottle of "universal solvent" by the PCB kit. I suppose anything volatile enough.

Having said that, there are probably things that are kinder to PCBs than that.

[Spandex]

On Thu, Jan 5, 2012 at 12:39 PM, Roger Light <ro...@atchoo.org> wrote:

 

We use flux cleaner and then a brush (cheap toothbrush is a good bet)
to give it a vigorous scrub, followed by a wipe off with a paper
towel.

I think I maybe was underestimating how much effort I had to go to with the scrubbing bit.. I kind of thought it was a "dissolve and wait" sorta thing.  Guess I need to put a bit more work in :)

If you're using external flux (ie. not just in the solder), it's
possible you're using more flux than is necessary, which will mean you
have more to clean up. I've seen it suggested that "you can never use
too much flux" but I disagree. It's best to keep your flux usage to a
minimum - only use what you need and don't assume that everything
needs flux. I mostly only use flux on fine pitch ICs or if I'm having
trouble with something.

I'm just using the flux in the solder.

Do you clean flux because it looks crap - or because it does damage to the PCB over time?  I've built a couple of fun Adafruit kits before but I wasn't that fussed about cosmetics or longevity, so I didn't worry about it.  Now I'm building things for my modular synth, I want to know they're going to last. Spending a lot of time inspecting my soldering, lining everything up right etc.

(if anyone's interested, I'm currently building a Synovatron CV Tools for my Eurorack - http://synovatron.blogspot.com/p/cv-tools-project.html).

Matt Spandex

[Spandex]

On Thu, Jan 5, 2012 at 12:40 PM, jfowkes <james...@gmail.com> wrote:

I've never had a problem with isopropyl, or the little bottle of "universal solvent" by the PCB kit. I suppose anything volatile enough.

Having said that, there are probably things that are kinder to PCBs than that.

Nivea for PCBs? :)

Matt 

[jfowkes]

Plain old E45 is fine, and much cheaper

By the way, the flux I use is this stuff:

http://www.rapidonline.com/Tools-Equipment/Brown-flux-jelly-61559

The pot I bought about three years ago is still almost-full, and I find you can get much more precise application of the stuff if you're taking it out of a pot than dispensing it out of a pen. You can also dip wires in it for tinning, which is immesely helpful.

Basically, I don't know how I live without the stuff, and would never go back to flux pens.