Homebrew PCBs

Leon / Andrew,

Sorry, I dont think i made myself clear, I was suggesting the emulsion used in silk screen printing to be put directly onto the PCB using Craig's spinning method, not through a mesh, oven dry it, then expose using UV and circuit pattern on a transparency or tracing paper as normal, the exposed area would remain and the circuit washed off with water ready for etching, if that makes sense! I was also wondering if the resist would stand up to the etching chemicals? the main reason is, this type of emulsion is a lot cheaper and easier to get than the dedicated PCB stuff! 

David

--- In Homebrew_PCBs@yahoogroups.com, "Andrew Volk" <amvweb@...> wrote:
>
> Leon -
>  
> But would the material use in the silkscreen stick to the copper clad and
> serve as a resist after exposure?
> 
>   _____  
> 
> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Leon Heller
> Sent: Saturday, April 14, 2012 3:29 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: [Homebrew_PCBs] Alternative photoresist chemicals - Idea?
> 
> 
>   
> 
> On 14/04/2012 21:24, David 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?
> 
> PCBs were made that way at English Electric Ltd, Kidsgrove, when I was a 
> student there in 1962. The pattern was created on a silk screen, it was 
> placed in contact with the copper, and the resist was applied with a a 
> squeegee.
> 
> Leon
> -- 
> Leon Heller
> G1HSM
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>