Homebrew PCBs

Brad

The simple answer is no.  Laser printers did not exist then so toner transfer was not possible.  Silk screen materials were available and you could do a screen if you had access to a college art department.

Again you could cheat by doing a colour laser printout thermal transfer.  You  need some means of aligning the image to the board.

Malcolm

I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.
Ha-ktovet al ha-kir

--------------------------------------------
On Wed, 9/30/15, 'Brad' unclefalter@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:

 Subject: RE: [Homebrew_PCBs] G-10 questions
 To: Homebrew_PCBs@yahoogroups.com
 Date: Wednesday, September 30, 2015, 5:51 AM
 
 
  
 
 
 
   
 
 
     
       
       
       Thanks muchly Malcolm.  That
 makes things a lot clearer.  Question – did you do any
 silkscreening back then for parts placement?  I notice in
 the plans printed by Radio Electronics, they had the
 printouts for the copper side, but also silkscreening for
 the non-copper side to aid in parts placement.  I’m
 wondering how a home hobbyist at the time might have pulled
 that off, or if they did.  From: Homebrew_PCBs@yahoogroups.com
 [mailto:Homebrew_PCBs@yahoogroups.com] 
 Sent: Tuesday, September 29, 2015 4:15
 PM
 To:
 Homebrew_PCBs@yahoogroups.com
 Subject: Re: [Homebrew_PCBs] G-10
 questions    Back in those days I used two
 methods:
 Copper clad FR4 was available, but
 a lot of SRBP was used as it was much cheaper.
 The first method was to paint, by hand, using
 mothers thinned nail varnish onto a carbon paper print
 traced from the layout printout.
 There was a
 great negative photo resist, KPCR, made by Kodak, sadly no
 longer available that you exposed to ultra violet light
 through a negative transparency of the of the layout.
 Then developed in a solvent based solution that
 coloured your fingers red for at least a week if you got it
 on them.
 
 So you would not
 be cheating if you used modern pre-sensitized copper FR4
 from companies such as Mega,
 <http://www.megauk.com/pcb_laminates.php>
 or a dry film:
 <http://www.instructables.com/id/Fantastic-Double-Sided-PCBs-at-home-using-photores/>
 or
 <https://www.youtube.com/watch?v=cRCFGZxmob0>
 
 Malcolm
 
 I don't suffer from insanity I enjoy it!
 Mene, mene, tekel, upharsin
 The
 writing is on the wall.
 Ha-ktovet al
 ha-kir
 
 --------------------------------------------
 On Tue, 9/29/15, 'Brad'
 unclefalter@... [Homebrew_PCBs]
 <Homebrew_PCBs@yahoogroups.com> wrote:
 
 Subject: [Homebrew_PCBs] G-10
 questions
 To:
 Homebrew_PCBs@yahoogroups.com
 Date: Tuesday,
 September 29, 2015, 11:51 PM
 
 
  
 
 
 
 
 
 
 
 
 
 Hi guys,
  I’ve been continuing to
 research and
 amass parts for my TV Typewriter replica build.
  I have a blog of it here:
 http://bradhodge.ca/blog 
 -- mostly working
 on the case right now to inspire me to
 push
 forward, but I’ve succeeded in getting almost all of
 the vintage 1973 or earlier chips I needed. 
 Now I’m down
 to the PCBs again.
  I guess I’m still
 kind of
 ‘green’ on this sort of thing.  Ideally, I’d
 like to do my PCBs the way they would have in
 1973.  But I
 still don’t understand how
 that worked.  Don Lancaster
 said the boards
 used were green G-10.  I found this on
 ebay: 
 http://www.ebay.com/itm/16-Green-G-10-FR4-Sheets-032-Thick-x-28-x-7-25-G10-Material-/141719358328?hash=item20ff21cb78
  I guess what I’m having trouble
 with is
 understanding how a home PCB maker in 1973 would
 have gone about getting copper onto these
 boards and copying
 the artwork from the
 article.  Is there any really good,
 baby-steps reading out there?  I just want to
 understand
 the original process and if it is
 possible to replicate it
 here in 2015.  I
 sort of understand the idea behind photo
 lithography.. I’m just not understanding how
 copper ends
 up on board, etc.  Much
 appreciated!  BRad     
 
 
 
 
 
 
 
 
 
 #yiv0643880995 #yiv0643880995 --