Homebrew PCBs

On Tuesday 27 April 2004 11:04 pm, Dave Mucha wrote:
> > > The benifit of mechanical etching is no chemicals.
> > > the down side is the expensive cutters that wear out quickly.
> >
> > I have the impression that this is more of a problem with some
> > board materials than others,  is that the case?

> Yes, FR-4 is the most common and easiest to get.  Seems no one knows
> were to get boards as the question on here rarely gets an answer.

That's what,  that green stuff?  Is there a FAQ about board materials 
someplace?  I saw phenolic referred to as well as FR-4,  so I figured that 
they were two different things.  <g>

> But the phenolic boards are much gentler on the cutters, but it does
> not really matter if you can't get the darn things.

They've gotta be out there somewhere.  Where *do* people go to get raw board 
material?  Only stuff I've gotten so far was an assortment pack at Radio 
Shack,  aside from some of their perfboards and such.

> > > A dull cutter will raise a burr on the copper and dependong on
> > > your hold-down method, will or will not effect the rest of the board.

> > I haven't yet begun to explore the possibilities of various
> > holddown methods.
> >
> > I can think of a few right off the top of my head,  those being
> > simple clamps,  some kind of a T-slot table (more clamps),  or maybe a
> > vacuum holddown setup.  What else is there?

> Duct tape.  No, really.

Would that be flat enough?

> I have a pair of pins in the table  the board slips over them for
> alignment and from there the boards is held on the edges with duct
> tape.

Ok.

> The drill does not lift the board and mechanical etching is held firm
> with the two pins.

I'm figuring on building a smallish table,  and then putting another hunk of 
material on top of that for "sacrificial" purposes,  so I won't have to worry 
too much about it.

> > > Another plus for the CNC is drilled holes.

> > Yes,  that's a big plus in my opinion.  I'd *much* rather have the
> > machine do that than have to do it myself...

> And THAT is why CNC-PCB_design was created !

Works for me!

> the non-technical, home brew drilling concept you can build from
> stuff laying around to spending $100.00-200.00 in parts.

And I have a *LOT* of "stuff laying around".  Got a whole box of assorted 
stepper motors scrounged out of various floppy drives and printers,  more 
transistors and chips than I want to think about,  enough passive components 
that I really don't think I'll need to buy any anytime soon,  and more.  
About the only thing I can think of that I might want that I don't already 
have is a couple of good-sized hunks of threaded rod...