Hi Andrew, here is a link to a pretty good PDF for "art" type etching. It gives both etchant formulas and resist formulas. Knife makers and jewelry makers use this and there are tons of other links in Google.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CFYQFjAE&url=http%3A%2F%2Fwww.ganoksin.com%2Fftp%2Fedinburg-etch.pdf&ei=MvlJUZS-Cob9ygH1-YBw&usg=AFQjCNGgUEVmymd6RCPzoZAZLEHVGbUS0Q&bvm=bv.44011176,d.aWccary
PS, hows the EDM working?
--- On Wed, 3/20/13, Andrew <a_wake@...> wrote:
From: Andrew <a_wake@...>
Subject: [Homebrew_PCBs] Re: etching the OD of a cylinder to create a graduated dial
To: Homebrew_PCBs@yahoogroups.com
Date: Wednesday, March 20, 2013, 12:56 PM
I went back and looked at some dials, and revised my estimate -- I think a line of .005" to even as much as .010" would be acceptable, unless the dial is very small. I have made a sample PCB using.005" lines with TT, but it was pretty iffy.
If I understood correctly, you said that a photo resist method of etching dials has been done? It would seem like this would be the best approach for etching. Perhaps a spray-on photo resist would work well?
I've not worked enough with wax to have a feel for how well that could work, either in terms of transfer or in terms of resist.
Again, I look forward to what you come up with ...
--- In Homebrew_PCBs@yahoogroups.com, "Rick Sparber" <rgsparber@...> wrote:
>
> My gold standard are the dials on my Craftsman/Atlas lathe. My guess is
> those scribed lines are around 0.002" wide and the numbers are all perfect.
> It was build around 1964 so probably done with a machine. Not much CNC back
> then.
>
> Rick
>
> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Andrew
> Sent: Wednesday, March 20, 2013 9:11 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Re: etching the OD of a cylinder to create a
> graduated dial
>
> This picture is certainly helpful, but does raise some questions. I notice
> some waviness in the outlines, but I am guessing that may have been
> intentional? For a machine tool dial, anything less than narrow, crisp,
> straight lines will reduce its usefulness. Normally when I make a dial or
> something similar, the width of the line I cut in the metal is in the
> vicinity of .001" to .002" -- just a slice made with a sharp tool. I have
> doubts about the feasibility of producing consistent, clearly visible lines
> of that width by etching around a pattern (leaving the lines embossed) as
> Rick is proposing to do.
>
> Again, half the fun of inventing is proving the doubters wrong! I look
> forward to seeing what Rick will come up with.
>
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