Homebrew PCBs

On Sat, 02 Jul 2005 09:33:28 +0200, mihai_hagianu  
<mihai_hagianu@...> wrote:

> Hi guys,
> i have tryed before, and restarted now to experiment with
> electroetching, as an alternative method to FeCl3.
> I and up with the same problem all the time. The electric courent is
> peeling off any stencils i'm using. I have tryed toner, different
> paints i've found here in the house(few oil based,acrilic,enamel), and
> even sticky tape(  ).I have also tryed different acid for
> electrolite ( H2S04, HCl, acetic)in different concentrations, to see
> any improuvement, but the result is the same:
>  -if I put the board, with the selected stencil in the acid,without
> power connected to it, it lasts ok,
> - if I apply electricity to it, to start electroetching, it works ok
> for a while, but after some time, the stencils are peeled off, for a
> reson i do not undestand nor can prevent yet.
> - I have tryed to electroplate the board, to check if the peeling
> happens, and of course it does not.
> - I have tryed different current densities, but the peeling still
> happends...some times sooner, sometimes later.
> any ideeas what am I doing wrong ?
> thanx,
> Mihai


No idea here.
It doesn't sound right that the current should make a differece, if you  
have say a tape over the copper then it isolates it from the fluid at that  
spot, so there is no current acting here one would think? Does it creep in  
 from the edges or also get peeled in the center of large areas?


 From what i remember from the steel spring etching thing, they use  
automotive paint, several layers.


Also, what good will electroetching do? at some point you'll loose the  
return path anyway? How could you ever finish a board?

ST