Re: [CAD_CAM_EDM_DRO] Re: making PC boards

Jon Elson wrote:

> ---------------------------------------------_->
>
> dave engvall wrote:
>
> >
> > > I used to do boards with Kodak KPR using an intense UV lamp to
> > polymerize the photoresist, then develop with toluene. Still have
> > > some KPR if someone can't resist. :-)
>
> Arrgh! I remember ALL TOO WELL the hassles of using KPR. It was VERY
> touchy. The resist had low contrast, so any quality problems with the
> master
> films would make rotten boards. the exposure had to be just right, the
> development
> just right, and then you had to make the board etch real quick, or the
> resist
> punched through, and you got swiss cheese instead of solid copper.
> The stink and hazards of the developer (111-triChloroEthylene) were
> bad, too!
>
> The Riston dry film resist is SO much better in about 5 different ways!
> No toxic chemicals, the resist is tough as nails, never punches through,
>
> has a VERY wide exposure latitude and wide development latitude.
> You just can't lose with Riston.
>
> All it took was one test with the dry film, I threw all my KPR stuff
> out, and never looked back!
>
> Jon
>
> Hi Jon,

Guess I was lucky. First toluene may be nasty but probably better than tric. I suspect that you may not have been getting full
polymerization...or the tric was tearing up the polymer.
I think Kodak recommended toluene and I had it available in 5 gal cans. :-)
Still is sounds like the Riston is really nice to use. Boards are touchy enough without having to fight the system.

Dave