I have used a product called Plastik 70 from Kontakt Chemie for a while now.
You apply directly on the bare copper before soldering, and you can solder
through it. When done populating, you remove the flux and give it another
coating. Works for small runs and prototypes else I suggest  you go the
solder mask route for larger runs.

Stephan
----- Original Message -----
From: Giles <programmer1@HOTMAIL.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, May 04, 2000 4:39 PM
Subject: Re: [OT] PCB coatings


> I have noticed a surprisingly large number of chemicals for tin-lead and
> solder mask available at Fry's.  You might go look at that store if you
have
> one in your area.
> Don't bother trying to ask for help in the store.
>
> Best regards,
> Giles
>
> ----- Original Message -----
> From: Mike Knoll <knollm@LAFCOL.LAFAYETTE.EDU>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Thursday, May 04, 2000 8:55 AM
> Subject: [PICLIST] [OT] PCB coatings
>
>
> > I made a circuit boards, and now they're sitting there, with bare copper
> > exposed to air.  I found some products used to coat boards to prevent
> > shorts, but also thought oxidation may be a problem.  Has anyone had
> > oxidation of bare copper boards?  The coatings in Mouser are $15/can,
> > anyone found any cheaper solution?
> >
> > Mike
> >