Fwd: Re: [basicstamps] Is cleaning and coating board worthwhile?
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Mark,
I've got to agree with Allan. I build instruments for biology and chemistry
research that are exposed to only mildly harsh environments (nothing like
oil field!). If we don't coat our boards, we get all kinds of problems. I
would think that any outdoor installation should be coated (weather
monitoring systems, etc) and probably any circuit exposed to temperature /
humidity extremes (like maybe some of the automotive applications that
aren't mounted on the interior of the car). I'm sure I'll remember writing
this next time I have to service a board that has been coated! Just as a
possible solution; I use a tapered wire brush on a Dremel tool to remove
Conformal and most other coatings from the solder side.
Mike
>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.
_________________________________
Mike Walsh
walsh@i...
I've got to agree with Allan. I build instruments for biology and chemistry
research that are exposed to only mildly harsh environments (nothing like
oil field!). If we don't coat our boards, we get all kinds of problems. I
would think that any outdoor installation should be coated (weather
monitoring systems, etc) and probably any circuit exposed to temperature /
humidity extremes (like maybe some of the automotive applications that
aren't mounted on the interior of the car). I'm sure I'll remember writing
this next time I have to service a board that has been coated! Just as a
possible solution; I use a tapered wire brush on a Dremel tool to remove
Conformal and most other coatings from the solder side.
Mike
>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.
_________________________________
Mike Walsh
walsh@i...
Comments
I agree with the other comments on this subject. If you do use a
conformal coating, I highly recommend that it be a silcone type. It
is much easier to repair. If necessary, you can solder right through
it (with adequate ventilation.)
As to cleaning the boards, it is a good idea, especially if you have
high impedance analog circuitry, or if the flux is aggressive and
leaves a conductive residue. The proper solvent to use depends on
the the flux, of course, and some people swear by water soluble
fluxes and a dishwasher. Please be environmentally conscious if you
need the alcohol/CFC flux removers.
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.
-- best regards
Thomas Tracy Allen PhD
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
>Mark,
>I've got to agree with Allan. I build instruments for biology and chemistry
>research that are exposed to only mildly harsh environments (nothing like
>oil field!). If we don't coat our boards, we get all kinds of problems. I
>would think that any outdoor installation should be coated (weather
>monitoring systems, etc) and probably any circuit exposed to temperature /
>humidity extremes (like maybe some of the automotive applications that
>aren't mounted on the interior of the car). I'm sure I'll remember writing
>this next time I have to service a board that has been coated! Just as a
>possible solution; I use a tapered wire brush on a Dremel tool to remove
>Conformal and most other coatings from the solder side.
>
>
>Mike
>
>
>>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.
At 11:43 PM +0000 6/11/01, Michael wrote:
>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