Homebrew PCBs

Donald,

Thank you so much for this lead. I just placed the order for the negative photo resist and negative developer.

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of Donald H Locker
Sent: Friday, March 22, 2013 6:34 PM
To: Homebrew PCBs
Subject: Re: [Homebrew_PCBs] Re: etching the OD of a cylinder to create a graduated dial

Might I suggest using a commercial product first (to verify one part of the process using known commercial materials) then move to making your own photoresist? <http://www.vetco.net/catalog/product_info.php?products_id=937> is one example; I'm sure Digikey carries something like it. Many years ago, silkscreen photoresists were made with Elmer's Glue and some additive that I can't for the life of me remember. That would be what I would search for. (The sensitiser was a chromate or bi-chromate, I think.)

HTH,
Donald.
--
*Plain Text* email -- it's an accessibility issue
()  no proprietary attachments; no html mail /\  ascii ribbon campaign - <www.asciiribbon.org>

----- Original Message -----
> From: "Rick Sparber" <rgsparber@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Friday, March 22, 2013 8:25:15 AM
> Subject: RE: [Homebrew_PCBs] Re: etching the OD of a cylinder to 
> create a graduated dial Harvey,
> 
> Pantographs and lasers are all existing technologies. My hobby is to  
> invent new things, especially things that are simple. So if I could 
> apply some homemade mixture to the cylinder, do a contact print, and 
> then etch, I would be happy.
> 
> Rick
> 
> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Harvey White
> Sent: Thursday, March 21, 2013 1:29 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: [Homebrew_PCBs] Re: etching the OD of a cylinder to 
> create a graduated dial
> 
> On Thu, 21 Mar 2013 11:18:29 -0700, you wrote:
> 
> >Andrew,
> >
> >I know that photo etching has been done on flat plates so assumed it 
> >could be made to work on a cylinder. I would wrap the artwork around 
> >the cylinder and rotate it at a constant rate under the UV light. The 
> >missing link here for me is an easy to apply photo resist. I've 
> >always used pre-treated circuit board material and had good results.
> >
> >One option I may pursue would be to coat the cylinder with wax and 
> >then use engraving techniques to scribe through only the wax. In this 
> >way, mistakes can be fixed by reflowing the wax. Not sure how to do 
> >the numbers. This method probably would work but is too much effort 
> >for me.
> >If a spray-on photo resist could be made to work, that would be the 
> >key.
> 
> Try a pantograph and larger patterns to engrave the numbers. Another 
> option would be Laser engraving. You need to rotate the cylinder and 
> move perpendicularly to the axis. Same thing for normal engraving.
> 
> Might be worth the effort.
> 
> Harvey
> 


------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links