Homebrew PCBs

Homemade resist of potassium dichromate and PVA/gelatin/egg-yoke does not
stand up to HCl and hydrogen peroxide (I tried it).  It seems to work with
moderate results with ferric chloride though.  

 

Can someone try emulsion with ferric chloride and HCL/hydrogen peroxide?
Could 5 mil lines with 5 mil spacing be included?

 

Jeff

  _____  

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of David
Sent: Sunday, April 15, 2012 3:27 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Alternative photoresist chemicals - Idea?

 

  

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-dichr
omate-/180861035286?pt=Laboratorio_e_Scienze_Mediche
<http://www.ebay.co.uk/itm/Potassio-bicromato-Kaliumdichromat-potassium-dich
romate-/180861035286?pt=Laboratorio_e_Scienze_Mediche&hash=item2a1c286316>
&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
> >
>





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