Homebrew PCBs

> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]
> Sent: 29 February 2016 16:26
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Plotter ink as resist? (was: Re: [Homebrew_PCBs] Re: drill pcb)
> 
> 
> 
> On 2/28/2016 11:55 PM, Stefan Trethan stefan_trethan@...
> [Homebrew_PCBs] wrote:
> 
> "As far as I know Staedtler Lumocolor red is the best resist ink.
> It is still available and I am not aware of any change in the formulation?"
> 
> Hello, Stefan--
> 
> Thanks for your question.
> 
> IIRC, the ink may not have been a Staedtler product. The topic arose around
> the time that HP introduced its 7470 desktop plotter (early 1980s), and
> various experimenters were trying direct-writing PC resist application. One
> red ink in particular proved to work relatively well but then was withdrawn
> and reformulated which degraded its performance as resist.
> 
> Maybe it's time to dig out those mothballed HP plotters and try again....
> 

I have a number of plotters and plotting with a Staedtler Narrow Red gives enough etc resistance for reasonable boards, but a Narrow Red isn't very narrow, and is rally only suitable for pitches down to 0.05 or so.
I personally wouldn't use it on anything fine.  I must say I also have a 3d printer with an attachment to allow me to Mill PCBs with a Dremel but I have yet to try that in anger. 
I built it to drill holes for switches for a computer project...

> Thanks again, and 73--
> 
> Brad  AA1IP
> 

Dave
G4UGM