Homebrew PCBs

I would guess that you are aware of these, but in case you are not.

Pulsar's paper is coated with starch and will not pull properly attached
toner from a PCB.  The starch dissolves allowing the paper to float away
from the PCB.

Pulsar has a foil the will help bridge pinholes in the toner.  It does
not bridge missing toner.

The pulsar site also has/had a page on etching the pcb using a sponge. 
The mechanical action greatly reduces the etching time.  It uses Ferric
Chloride so a vent hood is a must.

Daniel Johnson

--- In Homebrew_PCBs@yahoogroups.com, "jc805sb" <jc805sb@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" javaguy11111@
wrote:
> >
> >  Are you trying to mount MEMs devices on a pcb or using a pcb for
making MEMs devices?
> >
>
> I am etching copper patterns which operate as the MEMS
> (the field calls it MEMS although there's nothing mechanical).
> I have pictures on my blog here,
> http://88proof.com/synthetic_biology/blog/archives/280
>
> The pictures show pretty poor etch results which
> I am trying to improve using the best SMT techniques first.
> Pad size/spacing is 1mm x 1mm with 0.125mm gap, or smaller!
>
> Other researchers in the field have made similar MEMS
> on flexi boards.  I can list some interesting articles
> if interested.  These boards move liquid droplets across
> surfaces (even vertical surfaces).  Though this requires
> maybe >+1000V.
>
> Something tangentially interesting, some researchers used
> an "aborted etch" method with multiple dips in etch and
> multiple mask steps, to make copper traces of different
> heights.  Not useful for standard PCB however they were
> able to use it as MEMS for nanoparticle separation.
> They used ferric chloride as the etchant and found it
> to be a linear etch, so the copper "steps" could be
> precisely made.   These steps were 10um to 50um or
> something.
>
>
>
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "jc805sb" <jc805sb@> wrote:
> > >
> > >
> > > I am etching general pcb's and also etching pcb's
> > > for MEMS devices.  The MEMS uses copper pads as small as
> > > possible so I am attempting to get down to 0.125mm (0.005")
> > > and am trying the laminator+toner transfer with treated
> > > paper and "GreenTRF" process.  Others do this for SMT
> > > according to online sources so I am hopeful it will work.
> > >
> >
>