gEDA-user: DIY brass stencils

[Ben Jackson]

On Wed, Feb 21, 2007 at 02:57:08PM -0500, DJ Delorie wrote:
> 
> The issue is that, if you're etching through 5 mil of brass, you
> should expect 5 mil of undercutting.

You have to control the access of the etchant to the metal.  Maybe
a dithered fuzz of toner around the edge of the hole would allow the
center more access to etchant so you could go through before exposing
as much edge.  Eventually the isolated dots would just fall off as
the surrounding metal was eaten away.

I'm wondering if you use a scalloped hole like that, if the "bowl"
of solder paste will actually be peeled off by the lip all around
the edge.  You almost need to etch it from the board side so that
the opening "faces" downward.

-- 
Ben Jackson AD7GD
<ben at ben.com>
http://www.ben.com/