Perhaps the thin paper is allowing too much heat to come through. Either reduce heat/time or use thicker paper. I have found excellent results with Kodak (CAT 191 2369) Gloss photo paper. The type of toner may be a factor as well.
--- In Homebrew_PCBs@yahoogroups.com, "tda7000" <Tda7000@...> wrote:
>
> Hello everyone!
>
> I have recently discovered the toner-transfer method for making PCBs (I have previously used stripboard or dalo pen)
>
> I tried my first board last week and I used the instructions from: http://www.riccibitti.com/pcb/pcb.htm
> For the most part everything seems to work OK but I'm having some issues it seems with the toner spreading out too much.
>
> I am using a Lexmark T522 with original toner, and was using paper cut from the pages of an old "Next" magazine. I used an iron to do the .. ironing.
>
> The printer prints very crisp and clear and the toner sticks very nicely to the copper. The paper is also easy to remove afterwards.
>
> However, while still satisfactory and usable, some of the pads became a bit too big and some of the tracks did not have a well-defined straight edge.
>
> I was able to scratch off excess toner with a knife to make the pads smaller and etched the board anyway. I was using normal components and thick traces with overall quite a lot of room for error but I need to get this issue resolved if I want to make anything with fine tracks or SMD parts.
>
> But I am wondering what I did wrong? I tried twice to iron the board (first time I tried moving the iron around but also moved the paper and smudged the image and had to clean and re-do it).
>
> The second time I just held the iron on the paper, pressed down and waited about a minute.
>
> Can anyone who has done this before give me some advice as to what might be the cause of my problem??
>
> Thanks in advance.
>