Thanks for the info Craig - I'm sure photo resist is better than TT, but I'm comfortable with TT, it does what I need. I use large pads and traces so they don't lift while soldering..... for the 3 or 4th time<:) - it seems most of my boards wind up being prototypes as I tend to change as I build/solder on the board. Remove, change, replace components, etc.
Ken H>
--- In Homebrew_PCBs@yahoogroups.com, "designer_craig" <cs6061@...> wrote:
>
> Spin coating has been around for years. In the early semiconductor days it's how they would coat the wafers for processing.
>
> You can get micron accuracy with photo resist processing the best you are going to do with TT is about 600 -1200 dip if you are lucky.
>
> I don't believe the Shipley AZ111 is availabe anymore but there are similar products. I did buy some Genesis AQ3000 a couple of years back to give it a try. It is water based and worked as well if not better in the spin coater than the AZ111. I found it on ebay but had to buy a quart for about $65. Other than ebay I have not found a low cost low volume distribution cannel. It doesn't help that most PCB fab houses use dry film, so the market is not there any more.
>
> Once coated and baked you just use the a film master and a UV light source to expose the board. Development for the AZ111 and the AQ3000 were sodium carbonate based solutions.
>
> Craig
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "sailingto" <sailingtoo@> wrote:
> >
> >
> > Now that is just too cool!!!
> >
> > This is a method to coat standard old PCB boards to use in photo resist? I understand photo resist does better than TT, but have not tried photo resist due to cost of factory boards, etc.
> >
> > Craig - can you provide more info on this method? Cost? Where to buy chemicals? As asked, how to drive dust free?
> >
> > The boards are then handled as regular factor coated boards?
> >
> > Thanks for any and all info,
> >
> > Ken H>
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "David" <dgh2259@> wrote:
> > >
> > > Craig,
> > > Seriously impressive method of applying photo resist, certainly food for thought!! Beats the laminator method hands down!! How do you dry the board after? [and keep dust off it!!]
> > > David
> > >
> > >
> > >
> > > --- In Homebrew_PCBs@yahoogroups.com, "designer_craig" <cs6061@> wrote:
> > > >
> > > >
> > > >
> > > > Wayne,
> > > > I used to spin all sorts of boards. Used Shipley AZ111 for the resist. This was a solvent based, I would pre wet the board then spinn off the excess. I have also tried the AQ3000 water borne resist and that works just as well, possibly a little better.
> > > >
> > > > Small boards are not a problem nore are double sided boards. As the boards get larger it becomes harder and harder to get them centered on the spin table. Also the slinging forces between the center and outer edge vary greatly as the board gets bigger. I think the largest board I did was 8" x 8" though I would bet I could have done 10 x 10. Rectangular boards are the hardest to do.
> > > >
> > > > My first spinner was built from some sort of fractional HP motor and and aluminum plate, mounted in a cardboard box -- you do have to trap the excess resist that gets thrown off or you will have a mess. My latest unit is a little nicer and built from an old computer fan and a wood framed box with a splatter shield.
> > > >
> > > > https://picasaweb.google.com/115378886522213655693/DYIPCBs
> > > > Second photo is a short movie
> > > >
> > > > Board is held on with double stickey tape.
> > > >
> > > > Craig
> > > >
> > > >
> > > > --- In Homebrew_PCBs@yahoogroups.com, "waynehcausey" <wayne.causey@> wrote:
> > > > >
> > > > > Any experience with spin coating small PCBs? Equipment, RPM, photoresist, etc.
> > > > >
> > > > > Wayne
> > > > >
> > > >
> > >
> >
>