Flux removal question

[Harry Bissell]

I like to...

1) remove any flux I can with a sharp pointed object, like an
awl or x-acto knife. If you are scratching the PCB, or soldermask
you are using too much force. The flux I use cracks away like
hard candy. It has a sticky or gummy consistancy after that.

2) Remove the flux with an old toothbrush... this gets all the mechanically
removed flux off.

3) hold board at an angle and spray, so the remains of the flux can
flow downhill and be carried off the board...

4) Use the toothbrush again (I use a different one for this stage) if
there are any tough spots.

5) Final rinse with the spray..

Other ideas... use a water soluble flux and a dishwasher... (I don't know if
I want to wash the PCB and the bowl from my Rice Krispies  at the same time....)

or use "no-clean" flux.   I have not done either one yet. I still have about a
5yr. life on my
current roll of flux solder...

DON'T mix water soluble and standard flux on the same board. They don't like
each other and you will make a major mess !!!

H^) harry

Paul Wilkinson wrote:

> Here's another flux removal question - How do you do it?  Do you just spray
> it on and let it dry, or do you have to get in there with a Q-Tip?  And do
> you need to do it soon after soldering?
>
> My flux remover came with a billion warnings all over the can AND another
> sheet of warnings attached with a rubber band - but no instructions!
>
> - Paul
>
> ------Original Message------
> From: Harry Bissell <harrybissell at prodigy.net>
> To: Blandon Ray <arp2813 at home.com>
> Sent: June 18, 2000 3:54:03 AM GMT
> Subject: Re: Flux removal question
>
> You seem to be right on target. I would avoid flux cleaner on
> 1) Polystyrene caps
> 2) Pots and Switches (it will remove lubricants etc...)
> 3) Jacks  (could leave a residue...)
>
> I washed my PCB before installing these components.
>
> Flux leakage can be a problem around high impedance areas like the VCOs,
> S/H etc.  I usually try to scratch the flux away with an x-acto knife (gets
> brittle
> after about a day, flakes off easy) then clean with a swab.
>
> Your caps might be OK and they might be toast. Can't tell if they are
> damaged
> until you fire it up. I'd try first...they might be fine.
>
> H^) harry
>
> Blandon Ray wrote:
>
> > Actually a few questions, especially for those of you building the Mini
> Modular:
> >
> > After last night's round of soldering I sprayed the back of the board with
> some
> > flux remover. When it dried, some of the clear plastic polystyrene
> capacitors had
> > turned white on the outside. My questions are: first, is this likely to
> damage the
> > caps themselves? Second, what else shouldn't I spray with flux remover?
> Finally,
> > how important is it (generally speaking) to remove flux from analogue
> circuits?
> > I'm told it can cause problems related to current leaking around the
> board, but
> > that's about all I know.
> >
> > Thanks in advance,
> > blandon
>
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