Subject: laser vs. acid engraving?

From: Tom Kreyche <[email-masked]>
Date: 3 Nov 1995 07:01:15 GMT

Is anyone familiar with laser and acid etch engraving techniques?

I've worked out the design for a couple sundials, to be engraved on flat
plates. Investigation of engraving costs are shocking! I was quoted $1200
for a 12x18 inch pieces.

I'm ready to build my own laser setup or acid photo-etch setup, yes it
sounds a bit complex and messy, but what the heck. I'm an electronics
engineer and ham radio guy but haven't played with lasers (yet). 

Any pointers appreciated!

Tom

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From: [email-masked] (Rick Cook)
Date: 5 Nov 1995 16:25:12 GMT

>Any pointers appreciated!
If you can make your own printed circuit boards you can surely acid-etch
your own sundials.

The process isn't difficult. Just coat the stuff you don't want etched with
resist and dunk in acid until done. Swimming pool acid works fine.

However as with any process there are details to watch. For example the
piece must be completely clean and grease-free when it goes into the etch,
you will probably need to agitate the piece, etc.

The best simple explanation of the process I've seen is in "Step by Step
Knifemaking" by David Bowe. Also, do some experiments and make sure you've
got the kinks out before you commit to something you don't want ruined.

--RC

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From: [email-masked] (darylb)
Date: Mon, 06 Nov 1995 16:51:32 +0000

> resist and dunk in acid until done. Swimming pool acid works fine.

You should just go to an Electronics supply (components) store and get the
PCB stuff. MG chemicals (Kodak) has stuff called KPR. The whole process as
basically photographic.  And rather than acid get some etchent like ferric
chlorid or ammonium persulphate. Much more user freindly.
I did my own Sundial this way and being a neanderthal I did it in 3/8"
brass (18"dia) with a 1/2" thick gnomen so it wouldn't flex and give bad
time. My gnomen is etched on both sides but if you hear of a good way of
doing this (other than extreme caution against scratches) let me know. I
have an astrolabe design ready to go but have to do a lot of double sided
etching and unless I hear something good soon I'll start enquiring about
farming it out.