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From: email@example.com (Tom Bruhns)
Subject: Re: Etching!
Date: 18 Oct 2002 12:38:04 -0700
NNTP-Posting-Date: 18 Oct 2002 19:38:04 GMT
John Popelish wrote in message news:<3DB011CC.firstname.lastname@example.org>...
> Sounds like you did everything right, except wait long enough for the
> ferric chloride to finish the job. Most people heat and agitate the
> etchant but I prefer a different method for single sided boards.
> I put the etchant in a plate or saucer and fill it just far enough
> that the board will sit on the surface copper side wetted in the
> etchant while it rests o the plate at the 4 corners.
I use basically the same technique as John describes. For small
boards, I just float the board on the surface of the FeCl3 solution.
Surface tension is enough to hold up several square inches (tens of sq
cm) of board, generally. For large boards which don't seem to fit any
available etching tray, I'll put little holes in the margins and
install nylon screws to hold the board up. If I'm impatient, I'll
heat the etchant a bit, but room temperature works fine with patience.
The method has an additional advantage of producting very little
"undercutting" because the spent etchant seems to accumulate on the
little shelf of photoresist as the undercutting starts, and protects
it from more etching there. At least, that's my theory; in any event,
I can see a distinct difference between a board etched "inverted" like
that and one with the etched surface facing up, when looking under a
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