Apparently the foil has a thin, strong, dimensionally stable backing that
remains on the foil after etching.

Also, surplus PCB blanks are the preferred hobbyist material primarily
because we have no alternative, other than wirewrap and point to point.
 The special foil used here is US$45 for 5 8x10" sheets and US$80 for 10
8x10" sheets, and this method has very little waste, one sheet can make
several smaller boards.  Convenience, ease of use, and final results count
for a lot.  This method doesn't require a darkroom, exposures, UV light
source, or any chemicals except the etchant.  Plus there is no time
required for drilling, and aligning both sides of a double sided board is a
snap.  Anybody with just a laser printer can use this method, and a copier
will work well too if you don't use prepunched perfboard (it's hard to get
perfect 1:1 copying on any copier).

In any case, this certainly looks like it is worth trying.  Incidentally,
the author now uses this method for all his prototype boards, event those
that will have a high volume production later.

CIAO - Martin R. Green
elimar@bigfoot.com

----------
From:   William Chops Westfield[SMTP:billw@CISCO.COM]
Sent:   Tuesday, September 30, 1997 6:44 PM
To:     PICLIST@mitvma.mit.edu
Subject:        Re: [OT] A new way to make PCB's

    After all our discussions recently about plotting directly on a PCB
blank,
    the November 1997 issue of Electronics Now has details of a new method
for
    making PCB's that promises to be the easiest yet.
        :
    In a nutshell, this method involves printing the copper pattern
directly on
    a special flexible foil, which is then etched in a relatively benign
    etchant solution, all before actually affixing the pattern to the PCB.

Um.  What supports the copper pattern after it's etched, before it goes
onto
the backing board?  Better be pretty tough stuff.

This neglects that the preferred hobbyist PCB material is "surplus" scraps
sold at about $0.01 per sq inch of copper (ie, $0.02c/sq inch for double
sided boards.)

BillW