24 Oct
1999
24 Oct
'99
12:41 p.m.
First of all, I haven't read ALL of this thread, but I recall Tony or
someone else replying to him saying something about the method for making
plated through two-sided boards in your home. I've never met anyone aside
from professionals with scads of equipment who could do
that, but it seems
to me that the method which was described to me was to start with
bare
fiberglass/epoxy panels, drill them, then apply a slightly conductive
coating in liquid form which had to be forcibly dried (perhaps baked) before
the resist was applied. The boards were then exposed, the films applied to
registration targets on each side, to a powerful UV light, for which some
prefer to use direct sunlight, and the boards subsequently developed, then
etched.
Has any of you ever encountered an approach to this that could be managed in
the home environment with equipment costing, nominally, less that a k-buck
or two and achieving nominally 10-mil traces with 8-10 mil separation or
anything close to that? How about a dry-film solder mask?
Please share your experience, real or semantic.
Dick
-----Original Message-----
From: Roger Merchberger <zmerch(a)30below.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, October 24, 1999 5:21 PM
Subject: Re: OT: how big would it be? - PCBs at home
On or about 07:15 PM 10/23/99 +0100, Tony Duell was
caught in a dark alley
speaking these words:
work.
Oh, don't get me started on trying that... And
that toner-transfer film
isn't that good either...
Isn't that good? My, you're certainly in the mood of understatement today,
Tony. I've tried that stuff (thinking... This is cool. I can finally
prototype PCB boards for my classic interfacing projects relatively
easily...) and I can officially say that it really, really, really sucks.
And the worst part? It's not that cheap, either.
(certainly affordable, if it worked... which it doesn't.)
For the problems with acetate, try getting a transparency film designed for
the actual printer that you intend on using. Toners are quite different,
including their fusing temperatures, fineness, and other factors. Another
thing to watch for with this iron-on crap (or laser film, or whatever):
Don't run it thru the printer twice. The high fusing heat changes something
in the media that seems to make it right close to worthless the 2nd time
round.
I think that's what happened to me; the 600 DPI HP's use a
"micro-toner"
which fuses at a higher temperature, and I think it changed the media so it
wouldn't "iron-on" easily, not to mention I don't think the iron got
hot
enough to xfer the toner if that's a factor on the process working right.
Some of the newer "photo" inkjets might work pretty well for artwork,
too... My wife's Epson Photo 700 does this thing called "micro-weave" for
the photo papers. It essentially takes 1/4 swipes at the image, and prints
the image 4 times at 1/4 density with the full printhead, so there's
virtually no banding. I've not tried it (have a laser) but it just might
As always, YMMV and all that...
Roger "Merch" Merchberger
=====
Roger "Merch" Merchberger -- zmerch(a)30below.com
SysAdmin - Iceberg Computers
===== Merch's Wild Wisdom of the Moment: =====
Sometimes you know, you just don't know sometimes, you know?