Laser Printer/Photo Copier for Press N' Peel Blue

[formerMember1]

hey guys, sorry to bother you again but i have one more question,...

I made my 1st board, (axis face board,) and it came out perfect, then i made the output buffer board and that came out perfect, but when i made my wah board, i guess i heated it too long becuase the pnp blue moved and the board stick to the iron, after cooling when i took off the pnp, the toner transferred but in the one corner, most of the traces are spread from i guess being too hot, but still OK.  Anyway, my reason for post was becuase i heated the board up too long during ironing, it changed to a brownish orangish color in most parts of the board.  Should i clean the board again with Bon  Ami before i etch it so that it etches better?  or will the etchant eat right through the oxidation?  I was wondering if the bon ami cleanser will hurt my ironed pnp toner layout on board?

thanks

[Mark Hammer]

You would be surprised at the sorts of things that impair etching.  I always like to warn people about "finger juice".  While skin secretions might seem to do nothing more than take a bit of the shine off the board, mere fingerprints can result in an area that takes 3 times as long to etch as neighbouring areas.

And that's a point worth remembering.  It not so much the idea that the entire board has to be as pristine as a mirror.  Rather, when there are discrepanices between how quickly area A and B and C are etched, you canend up damaging the traces on the fastest-etched areas while waiting for the slowpoke areas to catch up.  Remember that the etchant doesn't "know" to only etch vertically (i.e., from the surface towards the fibreglass board).  Once a copper area has been etched away down to the fibreglass, the etchant starts working at the *sides* of the traces, and that's where your heartache begins.

I say clean the board and start over.

And yes, part of the art of using pNp is learning how to iron long enough to transfer the whole pattern, but not so long that you make "splat" of the traces.

[formerMember1]

OK thanks Mark, I will remeber this,... 


****EDIT***
I cleaned with bon ami, then etched it anyway, just to learn,  It did etch fine, but i did have some trouble like you said Mark,
the parts where it was not sparkling clean, etched way slower, one or two traces were just on the verge of being eaten away.
But in the end, it is fine, i also tinned it as i think you mentioned in another thread.  Except i used electronics  paste flux, i couldn't find liquid flux.  But it works good....

thanks