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Path: utzoo!mnetor!uunet!seismo!husc6!hao!oddjob!gargoyle!ihnp4!alberta!calgary!amc-vlsi!dale
From: dale@amc-vlsi.UUCP ( AMC Staff)
Newsgroups: sci.electronics,rec.audio,rec.ham-radio
Subject: Re: PC board photo etching kits
Message-ID: <371@amc-vlsi.UUCP>
Date: Fri, 10-Jul-87 11:41:01 EDT
Article-I.D.: amc-vlsi.371
Posted: Fri Jul 10 11:41:01 1987
Date-Received: Sun, 12-Jul-87 14:28:32 EDT
References: <2392@uwmcsd1.UUCP> <885@kodak.UUCP> <5775@pitt.UUCP>
Organization: Alberta Microelectronic Centre, Calgary, AB.
Lines: 37
Summary: P.C.B. preparation for etching
Xref: mnetor sci.electronics:937 rec.audio:2452 rec.ham-radio:1909

In article <5775@pitt.UUCP>, hoffman@pitt.UUCP (Bob Hoffman) writes:

> thing is extreme cleanliness of the board being sensitized -- this means taking
> scouring powder to clean any oxidation and oil off the board.  Use 600-grit
> wet emery paper or steel wool if necessary.  I don't like steel wool for the
> bits of steel it leaves behind.  That board should positively GLEAM when you're
> done.  Then, handle it only by the edges -- the oil on your fingers is enough
> to screw up the photoresist.


      In my most recent employment I was involved in P.W.B. prototype
fabrication both single and double sided. The problems with steel wool
pieces are solved using 600-grit emery paper, however this is still
too abrasive and you remove more cladding than you should. The best
cleaning method that we developed is as follows:

- Cut appropiate size board, and debur edges.

-Hot water, Comet (household cleanser), and Scotch-Brite.
      The hot water and comet remove the oxidization with the
      aid of the synthetic material scotch-brite. I don't
      know the commercial usage of the stuff but it will rip
      your skin off if you miss the pwb as your doing your
      work. The scotch-brite has added advantages, its cheap
      doesn't leave any residue etc.

- Rinse board in clean hot water, towel dry and immediately
  rinse with isopropal and allow to air dry on edge.

      We found that the board would positively "GLEAM" after
these steps were taken. Also process your cards as soon as you
can as oxidization has no concience. If you can't, leave them
in a isopropal bath until your ready.

Try it!

Dale K. Wlasitz