I don't know if the "bake" operation would really be helpful. The bake
step was important with the spirit-based polymers like Kodak KPR, etc in
order to
drive off any volatiles that might be remaining that could damage the
artwork, which was usually a piece of lithographic photo film.
If the Ulano emulsions can be thinned down to allow spin coating and
still do good imaging, then the scheme might work quite well.
If the Ulano emulsion has a spirit base, then perhaps a short term
mild-temp "bake" might be beneficial.
Someone needs to bite the bullet and purchase some of the Ulano stuff
and start experimenting.
I find that I'm usually "rolling the dice" when I use the toner transfer
method in that I'm never quite sure
how good result will be, even though I've tried to standardize my
technique as much as I can.
Roland F. Harriston, P.D.
∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗
David wrote:
>
>
> I think the general concensus is it will probably work, using the
> spinning method to achieve a thin uniform layer and baking it for a
> short while, then expose as normal, one less chemical to use as
> unexposed resist just washes off, not sure how well the exposed area
> will stick to the copper clad though, a few experiments should wrap it
> up though!
>
> Another interesting alternative to the various PCB and Silk Screen
> chemicals available is to make it yourself!
>
> A mixture of Potassium Dichromate [or bichromate] and Egg yoke, or
> dairy cream, will make a UV sensitive emulsion.[how this stands up to
> etching though........] not sure of the mixing ratios, but, it is
> toxic!! a carcinogenic, and chromium dermatitis are two of the more
> unpleasant results of getting in contact with the stuff!! it is sold
> on ebay amongst other places;
>
> http://www.ebay.co.uk/itm/Potassio-bicromato-Kaliumdichromat-potassium-dichromate-/180861035286?pt=Laboratorio_e_Scienze_Mediche&hash=item2a1c286316
> <http://www.ebay.co.uk/itm/Potassio-bicromato-Kaliumdichromat-potassium-dichromate-/180861035286?pt=Laboratorio_e_Scienze_Mediche&hash=item2a1c286316>
>
> if anyone would like to experiment?..........
>
> David
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "mark" <STRIPES97_USA@...>
> wrote:
> >
> > That's a good question as I was thinking about the same thing when I
> got a screen printing setup a few months ago, but haven't had time to
> even do more then open the box to make sure everything was in the kit...
> >
> > --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "David" <dgh2259@> wrote:
> > >
> > > Hi All,
> > > After looking at Craig's fasinating PCB spinning methods, an idea
> came to mind, seeing as the regular chemicals seem to be rare and
> expensive, has anyone tried silk screen printing emulsions? this in
> not the inks but the chemical used to make the pattern in a very fine
> mesh, the emulsion is spread over the mesh with a squeegy and after
> exposure to UV through the pattern[design] blocking transparency, the
> unexposed area is washed out with running water, the exposed area
> remains and is really pretty tough, is this resistant to etching
> chemicals? would this method work? has anyone tried?
> > > There would be no need to "develop" the PCB, just wash off with
> water!!
> > > I may be way off track with this but any comments and/or suggestions?
> > >
> > > David
> > >
> >
>
>
[Non-text portions of this message have been removed]