--- In
Homebrew_PCBs@yahoogroups.com, "cunningfellow" <andrewm1973@...> wrote:
>
> > rolynd33 wrote:
> >
> > What speaks against using a bernoulli type
> > sprayer for spray erching ?
>
> Volume.
>
> You don't need a mist.
>
> You want fairly large droplets.
>
At the moment I am etching with a bubbler tank and ferric, this works ok for pcb but I have begun fabricating small parts from sheet metal. As I am using 0,5mm thickness and it needs to be through etched undercut on fine details becomes a problem. I use double sided etching and have cranked up the temperature of the etchant to 55°-60°C to speed up the process but dimensional accuracy is not where I want it to be.
(BTW: I am using toner transfer with the oracal 651 plotter vinyl and I am getting better and more consistent results than with the thin glossy magazine and catlouge paper I used before. I use the transparent one for double sided designs.)
I was looking into methods that give less undercut and as far as I could discern spray etching gives the least undercut, right?
I have no experience with building a spray etcher and as far as I was able to see its difficult and costly to get the right pump and on the rotating tube type its not the easiest part to get them to run smoothly set the right speed and get the impeller to function perfectly.
As I already have a compressor I wanted to explore the idea of a sprayer without motors and pumps which would be a little easier to build and uses no costly parts. But the consensus here and the fact that no one has build a system this way leads me to the conclusion that this would not be the way to go.
I will be looking into the splash etching tank idea and do a little research into this direction.
Regards