Homebrew PCBs

Basic question: no-clean or water soluble?

With water soluble you really need to have a good cleaning system to
get ALL of the flux out from underneath the parts.  At my last job we
had a large industrial washer.  It worked fairly well, but in certain
areas it would not clean very well...

I still prefer using water soluble because it's easier for me to touch
up.  I've always just washed it off with extremely hot water and
scrubbed it with a toothbrush.  Worked fine, but I never had very many
large parts on the boards I've washed by hand.

I personally prefer the look of a nice clean board verses one covered
in no-clean or rosin core flux.

On Thu, Apr 30, 2009 at 10:23 AM, DJ Delorie <dj@...> wrote:
>
> Basic question: no-clean or water soluble?
>
>

-- 
Erik L. Knise
Pacific Shipping Company
Seattle, WA

No-clean. It can stay on if I'm lazy, or I can wash it off with rubbing alcohol or ultrasonic bath.

I choose water soluble. washing it works great at home and work with no problems. NoClean leaves residue which you can leave, looks crappy, hard to clean off and has caused problems in RF circuits.

Brian

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

>
> 
> Basic question: no-clean or water soluble?
>

At work we also use a large industrial washer and have no problems with the boards. I also like WS for touchups. Leaded is great, leadfree sucks all the way around. Oh by the way, I was using sponges to clean my tips off, leadfree... Now I use the brass brilo. it works great for removing oxides and doesnt damage the tip that I can tell, I havent had any problems so far. leaded I still use a sponge.

Brian

--- In Homebrew_PCBs@yahoogroups.com, Erik Knise <elknise@...> wrote:

>
> With water soluble you really need to have a good cleaning system to
> get ALL of the flux out from underneath the parts.  At my last job we
> had a large industrial washer.  It worked fairly well, but in certain
> areas it would not clean very well...
> 
> I still prefer using water soluble because it's easier for me to touch
> up.  I've always just washed it off with extremely hot water and
> scrubbed it with a toothbrush.  Worked fine, but I never had very many
> large parts on the boards I've washed by hand.
> 
> I personally prefer the look of a nice clean board verses one covered
> in no-clean or rosin core flux.
> 
> On Thu, Apr 30, 2009 at 10:23 AM, DJ Delorie <dj@...> wrote:
> >
> > Basic question: no-clean or water soluble?
> >
> >
> 
> -- 
> Erik L. Knise
> Pacific Shipping Company
> Seattle, WA
>

No-clean for me.

I just don't see how I could get the water soluble out from under QFN
packages and similar tight spots.

ST

You folks aren't making this easy for me...  ;-)

One thing I noticed about my current no-clean is that the residue has
(relatively) low resistance.  If I have a 25 mil gap between power and
ground, an inch of that results in 330k between them.  I end up
scraping between traces to get the hardened residue off.

I wonder if a waterpik would be enough to get those hard-to-reach
places that make people avoid water soluble flux?  I do have some QFNs
in my current project...

I don't think mine is so conductive - I hope not.

I can't imagine how anything can get the crud out from under a QFN
package. Even a BGA seems relatively easy by comparision. Basically
any component that sits flush against the board would seem pretty much
impossible to me.... (Obviously there ought to be ways that I can't
think of).

ST

On Sat, May 2, 2009 at 5:40 PM, DJ Delorie <dj@...> wrote:
>
> You folks aren't making this easy for me...  ;-)
>
> One thing I noticed about my current no-clean is that the residue has
> (relatively) low resistance.  If I have a 25 mil gap between power and
> ground, an inch of that results in 330k between them.  I end up
> scraping between traces to get the hardened residue off.
>
> I wonder if a waterpik would be enough to get those hard-to-reach
> places that make people avoid water soluble flux?  I do have some QFNs
> in my current project...
>

Noclean is hard to clean and may be conductive. I had problems in rf circuits even with my mega8 running at 8MHz. Just today I reworked 21 QFN's with water soluble flux and just swishing them in a tub of 140 degree water and drying the board they worked at 1 GHz. There was no problem washing the flux from under the part, it seems.

Brian

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@...> wrote:

>
> No-clean for me.
> 
> I just don't see how I could get the water soluble out from under QFN
> packages and similar tight spots.
> 
> ST
>

Talking about QFN's, they dont really sit flush. I use a 10X scope at work and can't see a gap but flushing with water cleans it out. There is the gap of solder between them that water can get to. It is easier to remove WS than NoClean (NC). Even hot tapwater will wash it out.

Brian

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@...> wrote:

>
> I don't think mine is so conductive - I hope not.
> 
> I can't imagine how anything can get the crud out from under a QFN
> package. Even a BGA seems relatively easy by comparision. Basically
> any component that sits flush against the board would seem pretty much
> impossible to me.... (Obviously there ought to be ways that I can't
> think of).
> 
> ST
> 
> 
> On Sat, May 2, 2009 at 5:40 PM, DJ Delorie <dj@...> wrote:
> >
> > You folks aren't making this easy for me...  ;-)
> >
> > One thing I noticed about my current no-clean is that the residue has
> > (relatively) low resistance.  If I have a 25 mil gap between power and
> > ground, an inch of that results in 330k between them.  I end up
> > scraping between traces to get the hardened residue off.
> >
> > I wonder if a waterpik would be enough to get those hard-to-reach
> > places that make people avoid water soluble flux?  I do have some QFNs
> > in my current project...
> >
>

Brian wrote:
> Noclean is hard to clean and may be conductive. I had problems in rf
> circuits even with my mega8 running at 8MHz. Just today I reworked 21 QFN's
> with water soluble flux and just swishing them in a tub of 140 degree water
> and drying the board they worked at 1 GHz. There was no problem washing the
> flux from under the part, it seems.

I was under the impression that most water-soluble fluxes were corrosive to 
some degree, and that No-Clean wasnt?

Although to be truthful I tend to use rosin-core solder wire and clean with 
IPA. Not sure what's in the solder paste, though (without digging it out of 
the sealed bag in the fridge and reading the label, anyway).

-- 
Phil.
ygroups@...
http://www.philpem.me.uk/

I will find out what kind of WS flux and paste we use at work and let you know monday.

Brian

P.S. I just made a board with a SMD mega8 using WS flux and used hot tap water to clean it and it works and looks great.

--- In Homebrew_PCBs@yahoogroups.com, Philip Pemberton <ygroups@...> wrote:

> I was under the impression that most water-soluble fluxes were corrosive to 
> some degree, and that No-Clean wasnt?
> 
> Although to be truthful I tend to use rosin-core solder wire and clean with 
> IPA. Not sure what's in the solder paste, though (without digging it out of 
> the sealed bag in the fridge and reading the label, anyway).
> 
> -- 
> Phil.
> ygroups@...
> http://www.philpem.me.uk/
>