Homebrew PCBs

Hi Alan,
        Layout blue is made to be just scratched. It has been around 
for 75 years. The trick is to have your traces drawn with an overlap. 
During the scratching process you can be sure the trace is isolated 
cleanly. The only drawback is all the traces are surrounded by a 
ground plane. This is the same result as milling them. I use the 
ground plane for my ground connections. Most digital circuits work 
just fine with the extra copper. High end receivers use ground 
planes. There is no simple way to make a PCBoard. Even sending them 
out can have headaches.

                                            Cranky 

--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi Brian, John,
> 
> What about using a diamond engraver tip?  I bought one (mistakenly)
> thinking it was for machining (it was for the Dremel engraver).  
But I'm
> thinking one could drag it around as well.  I can "read" Gerber 
files
> with my controller program, and I generate "outline" tool paths. 
from
> that.
> 
> Alan  KM6VV
> 
> Brian Schmalz wrote:
> > 
> > Crankorgan,
> >         Putting bluing on the whole board, then scratching it off 
with a
> > carbide metal scratch tip is the method I'm currently using to do 
boards. I
> > tape the copper down on a piece of paper, then run it through my 
HP plotter
> > (7550A). I get very clean lines and can get down to 10mil space 
10mil line
> > with a bit of practice, double sided. I've written custom 
software to take a
> > Eagle board file and create HPGL which I then output to the 
plotter. This
> > method really works well since you can use a standard plotter (I 
just built
> > a special 'pen' with the carbide scratch tip) plus some software. 
Anyway,
> > the bluing/scratching method is alive and well . . .
> > 
> > *Brian
> > 
> > -----Original Message-----
> > From: crankorgan [mailto:john@k...]
> > Sent: Saturday, September 14, 2002 6:41 AM
> > To: Homebrew_PCBs@y...
> > Subject: [Homebrew_PCBs] Re: Inkjet printing PC boards
> > 
> > Larry,
> >       I sell plans for a PCBmill (Brute) and I just finished a
> > machine that will mill or draw simple boards. (Morph)
> >       Months ago I brought up the idea of Scratch and Etch. This
> > idea is not dead. First I developed a super simple CNC plotter. 
Now
> > I have a machine strong enough to drag a scribe through the 
blueing.
> > Several people tried Scratch and Etch With good results. Coating 
the
> > whole board and then scribing and isolation between pads for 
etching
> > seems easier.