Re: gEDA-user: Isopropyl alcohol vs. ethanol

[Dave McGuire <mcguire@xxxxxxxxxxxxx>]

On Apr 24, 2006, at 11:42 AM, Marvin Dickens wrote:
> > >   Do you have any opinion on washing boards with something like  
> > > Alconox (a trisodium phosphate-based cleaner)?
> >
> > I wouldn't want a cleaner containing sodium. Sodium ions have high  
> > mobility in epoxy, especially in the presence of moisture. Sodium is  
> > soluble in SiO2, so it can shift transistor gate thresholds. It is  
> > common to passivate chips with a glass designed to getter sodium, but 
> >  that's not a perfect barrier.
> The way the question was posed, I think he was asking about using 
> alconox on bare, unpopulated boards - As a way of removing
> photo resist after etching. In this scenario, sodium should not be an 
> issue if the boards were properly washed and dried.

  Yes, I was talking about using Alconox on bare boards.  I'm sorry I 
wasn't more specific, I was half asleep when I sent that email. :)

  Specifically I would want to use it for cleaning & degreasing boards 
before assembly.  I use Alconox for many other non-electronic things, 
so I have a carton here.

          -Dave

--
Dave McGuire
Cape Coral, FL