Is cleaning and coating board worthwhile?

Archiver

I'm putting the finishing touches on a project, and I'm trying to
decide if I need to clean the flux residues off of the board and put
a final coating on the board. I've put a good bit of work into this
project, so I'd like to insure that it will last as long as
possible. Are cleaning the board and using a coating worth the
additional time and money?

I've been using Radioshack's "Silver bearing solder" (62%Sn, 36%Pb, 2%
Ag), primarily because it is a very thin solder that is easy to work
with on small circuits. It does leave a brown residue after
soldering, but doesn't state whether is is activated, mildly
activated, etc.

As far as coatings.......the local Radioshack.com carries Techspray's
acrylic, urethane, and silicone conforminal coatings. I'm not sure
which one to use, if any.

Any suggestions or comments would be appreciated.

Thanks,
Michael

Archiver

> I'm putting the finishing touches on a project, and I'm trying to
> decide if I need to clean the flux residues off of the board and put
> a final coating on the board. I've put a good bit of work into this
> project, so I'd like to insure that it will last as long as
> possible. Are cleaning the board and using a coating worth the
> additional time and money?
>
> I've been using Radioshack's "Silver bearing solder" (62%Sn, 36%Pb, 2%
> Ag), primarily because it is a very thin solder that is easy to work
> with on small circuits. It does leave a brown residue after
> soldering, but doesn't state whether is is activated, mildly
> activated, etc.
>
> As far as coatings.......the local Radioshack.com carries Techspray's
> acrylic, urethane, and silicone conforminal coatings. I'm not sure
> which one to use, if any.
>

Don't use any coatings. Conformal coatings are intended to protect circuits
from corrosion in harsh environments; they are a royal pain in the butt to get
off if you ever want/need to add to or repair the circuit.



Mark Hillier, VE6HVW
President, HVW Technologies Inc.
Canadian Distributors of Parallax Products and other Neat Stuff
Tel: (403)-730-8603 Fax: (403)-730-8903
See our NEW BASIC Stamp Prototyping tools !
http://www.hvwtech.com/stampstack.htm

Archiver

I suppose it depends on his application Mark. I build ruggedized
oilfield electronics, and I always conformal coat my boards. It is
probably not necessary on hobby projects though.

Allan Dobler

Mark Hillier wrote:
>

>
> Don't use any coatings. Conformal coatings are intended to protect circuits
> from corrosion in harsh environments; they are a royal pain in the butt to get
> off if you ever want/need to add to or repair the circuit.
>
> Mark Hillier, VE6HVW
> President, HVW Technologies Inc.
> Canadian Distributors of Parallax Products and other Neat Stuff
> Tel: (403)-730-8603 Fax: (403)-730-8903
> See our NEW BASIC Stamp Prototyping tools !
> http://www.hvwtech.com/stampstack.htm
>
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Archiver

I read a very informative magazine article recently (I'll post a reference
if I can find it) about an expanded PTFE membrane from W.L. Gore, that
solves the problem of moisture accumulation in environmental enclosures.
It's probably in one of the product families listed here:
http://www.gore.com/corp/separations/venting.html

>Condensation is the enemy in high humidity environments, or anywhere
>the temperature changes quickly or gets below freezing. Be careful
>in your circuit board layout to keep high impedance paths isolated or
>guarded, and higher voltages well separated. A sealed box +
>desiccant will be fine in many situations, and highly repairable.

Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
Manufacturer of the famous BOB-II Serial Video Text Display Module!