Retro Reproduction 2

rod rodsmallwood52 at
Sat Oct 24 03:05:49 CDT 2015

Er..  Wow!
            Ok the process mimics the original production system.
I draw the panel using Inkscape because it runs on windows and Linux,
produces .svg (scalable vector graphics) files and its free!!

As sources I use photographs, Scans (The best way because there are no 
lens errors) and drawings from print sets.

There’s usually a dominant layer or color.
For example pdp8's often have lines and text in white.

So what I do is to draw all the layers one per color.
As these will become the positives for the silk screens they are always 

To do check prints I have a HP DesignJet T120 (24" wide roll feed)
Printing on reproduction clear film would generate the master positives.
However the girls like to be able to tweak things so they get the .svg 
They have a printer all set up with repro film anyway.

I also have a plastics supplier who will not only laser cut the blanks 
to size
but do holes and cut outs as well.

So armed with my drawing files on disk and a pile of blanks its off to 
my silk screen printers.
If its a repeat order then they go and get the ready made screens. I own 
them and they keep them for me.

If its a new job then they make the screens. The screen on its frame 
gets hand coated with a photo sensitive
liquid which dries in a short time. The coated and dried screens are 
then exposed through my masters.
Where the black lines where can be washed off with water and hence let 
the ink through when printing.

The only real skill so far is getting the right amount of resist on the 

Now for the skilled bit.
The place is run by two very nice girls age about mid twenties.
They both have art degrees and are qualified colourists.

Getting the colors matched and getting the right mesh size saw them
sit down with their ink and screen rep and after about an hour I'm
told came up with the answers.

They can match way beyond a just noticeable difference and
being female (and there's no doubt about that) don't suffer from color 
blindness (which I do)

The final stage is the actual printing. They use vacuum printing tables.
They are about five feet square and about a foot deep. Also very heavy.
There’s a pattern of holes in the bottom and a domestic vacuum cleaner 
is used as an exhaust pump.
They also set up corner references to get each panel in the same position.
The screens are mounted on a sliding bar arrangement .
Getting this lot to register is a highly skilled job and not for the 

I can duplicate most panels (metal as well) but as they say in the USA 
"custom costs"

I'm setting up for my next run now. (artworks done) Its for PDP8/e (two 
types) 8/f and 8/m
I'm in the drawing stage for 11/45 11/55 11/70 (common blank size)

So given a scan and measurements  and a panel that's not too big
(max to fit on a 19" rack box) I can have a go at most types of panel.

Now we need a bezel production person/group, switches source and lamp 
panel producer.
3D printing for the switches possibly?

For one off panels I'm looking at flat bed printers. So far way to 

I hope this sets out what can be done.

Rod Smallwood

"If you take and do not give then soon there will be nothing more to take"

On 24/10/15 00:43, Mike Ross wrote:
> On Sat, Oct 24, 2015 at 11:22 AM, rod <rodsmallwood52 at> wrote:
>> Hi Guys
>> Well my missive on reproductions seems to have generated some interest.
>> There seems to be a lot of will to keep the old systems going and to
>> reproduce parts for them
>> and indeed build complete systems from new parts.
>> The main areas of interest are front panels (Not just DEC), key switches and
>> bezels.
>> Panels I can handle.  Who wants to be the focus for switches and who for
>> bezels?
>> More than one person for each category can only be a good thing. I'll call
>> them "The Makers"
>> Those who want the items I'll call "The Takers"  from 'I'll take one / some
>> if they get made."
> Do you think you will be able to do 'custom' or one-off items if you
> get the process efficient enough? I have a laundry list of panel bits
> I need...
> 1. A replacement perspex for a pdp-12; damaged in shipping :-(
> 2. I have a couple of pdp-15s - and both have the panels that were
> unique to the XVM incarnation of that system, like nothing else DEC
> ever made; stick-on flexible plastic sheets mounted to a metal support
> mask - see - I'd like convert one at
> least of those to the 'traditional' DEC style of perspex panel. I
> think that might end up being the only RP15 and FPP15 indicator panels
> you ever make :-)
> 3. There is ONE IBM system (that I know of) that uses perspex, similar
> to DEC: the System/360 Model 30. All other IBM panels are metal with
> individual lights mounted in separate holes. The Model 30 uses
> perspex: see
> Differences from DEC panels are... all the printing in on the front of
> the panel, there is no 'mask' for the lights printed on the back, and
> the light 'holes' in the print are not round, but characters -
> illuminated captions - and they're not clear holes but colored; some
> are translucent white, some are translucent red: see
> for the effect. Could you make one of
> those; another one damaged in shipping grrrrr? Full panel is split
> into two parts, see:
> 4. IBM metal panel consoles. I have a couple of these - System/370
> models 145 and 155 - which are complete but a bit ropy and rusty and
> damaged in parts; see: - They're
> just sheet steel painted black with the legend silkscreened (I
> presume) on. To restore these I need to remove the rust - which means
> removing the paint and the silkscreening... could you help with those?
> Thanks
> Mike
> 'No greater love hath a man than he lay down his life for his brother.
> Not for millions, not for glory, not for fame.
> For one person, in the dark, where no one will ever know or see.'

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