I think it is a bit of both. I have had a few pinholes on large fill areas when doing toner transfer before, I would touch them up with a Dalo pen and it was fine.
One board I didn't clean the toner off for a week or so. There was some pitting to the surface in the larger areas. I also only rinsed it with water.
Now, straight after etching and rinsing I put my boards in a baking soda solution to neutralize any leftover acid. Then I clean everything soon after and coat with flux, conformal coating or tin them.
But I have mostly been doing the UV process now, and with negative resist it is easy to do large planes and fills - you just print nothing!
--- In Homebrew_PCBs@yahoogroups.com, <w6nim@...> wrote:
>
> Just getting started with the toner transfer method.....
....Three or four days later, acetone in hand, I cleaned the traces, and found numerous pinholes on all the traces. I'm speculating that the toner absorbed minute quantities of etchant, and continued to etch until wiped clean. Is this a reasonable assumption - that cleaning immediately after etching is required? Or is the aftermarket toner suspect??
>
> Any thoughts would be appreciated.
>
> Norm
> W6NIM
>