[sdiy] pcb question

[Theo]

My Mac has system 6 and a BW screen, think my old XT is better suited for
PCB design :(

For home brew etching IMO its better to stay away from (long) 10 mil traces.
Its ok to use them for short distances though, for example to get between
two IC pins (try 8mil for SOIC).

With 30 mil traces I get good results with a inkjet printer on plain paper,
then spay with "Transparent 21" from Kontakt chemie / CRC Industries.
This stuff makes the paper transparent for UV.
For my this gave better results than using clear inkjet transparent!

Using wide traces the etching process is not critical,
just a tray with FeCl3 at room temp works OK.

When the layout needs a lot of 10 mil traces running close together, the
above method doesn't cut it.
I only use the 10 mil when I really have to, think fine pitch SMD or running
a bus though SO memory ICs (sick but it works!).

In this case I use a laser printer (or copier) to get the layout on
"calk"/"tracing-paper" (depending of your location on this planet).
The finishing touch comes from spraying with clear acrylic lacquer,
this dissolves the toner just a tiny bit and gets rid of the pinholes the
laser printer leaves in the black.
Only professional made film from a photo-setter tops the resulting film.

However the limitation now is in the etching process.
Using a bubble or spay etch machine 10mil traces work ok for single sided
boards.
But for dual sided layouts things get tricky, at least using my single
nozzle spray etch tank.
I have to turn over the PCB every 10 seconds or so, otherwise the tiny
traces get eaten away while etching the second side of the board.

HTH
Theo


From: <mostaware at mac.com>



> I'v started using OdmondPCB for OSX and it seems OK.  good for free.
> another mac users out there?  what are you using?
>
> here's my question.  What's a good trace width for a diy project?  I
> currently have my design set to 30 mil for trace width, the default was
> 10 which is far too thin in my mind.  I will be attempting to use
> DynaArt Design's toner transfer system to lay down my design to the
> board.  anyone else try this?  If it doesn't turn out so well, i just
> just go over it with a sharpie, right?
>