Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
> I didn't use the pulsar process completely, just the toner transfer 
> paper.  Their process uses another iron on transfer product, then 
> you scrub the board with the chemicals - didn't like that idea.

Yeah, I think they call the second layer "green" or some such.  

> 
> The "Bloom" I think you are referring to is from my touch up on the 
> toner where I thought I saw some missing spots - my hands are not 
> steady enough to just dab the spots so it looks kind of nasty.
> 

been there, done that...  Thank God the electrons don't care about
looks, though.  Your pressure is pretty good then.

> The pin-holing would probably be much less if I could figure out how 
> to turn up the density of this particlar laser printer 6P.  I don't 
> think it is putting down enough toner for a really good job.
> 

I use a copier to lay down the toner and even when I crank up the
density I still get pinholing.  It's the nature of the toner process.
 If you look at the transfered toner with a microscope, you can see
that it is still just a bunch of plastic particles.   However, with a
really fast etch, I find pinholing to be much reduced.  That's an
argument for hotter etchant.

I have some ideas to try out to further reduce pinholing - one is to
reflow the toner after it has been transfered.  One idea is use hot
air to melt the toner particles so they flow slightly and fill up the
pinholes.  Another one is to spray a light coating of acetone on the
transfered board.  Not enough to cause runs but enough to disolve the
toner and have it flow together.  I'm not sure where to get a sprayer
with acetone resistant parts, though.

Phil