Front Panels - PDP8 and PDP 11

Brent Hilpert hilpert at
Wed Mar 9 21:54:51 CST 2016

On 2016-Mar-09, at 3:35 PM, Rod Smallwood wrote:
> On 09/03/2016 18:36, js at wrote:
>> On 3/9/2016 1:03 PM, COURYHOUSE at wrote:
>>> In a message dated 3/2/2016 3:32:48 P.M. US Mountain Standard Time,
>>> rodsmallwood52 at writes:
>>> ...
>>> The only  process deviations I have allowed myself are as follows:
>> Rod, very interesting!  Do you have a description of the full process?   Or what is the process after the screens are made?
>> Thank you-
>> -John
> Well after the screens  are made Then to do the actual printing you need a very skilled hand screen printer with
> at least ten years experience.  Getting five or six layers (some on the front and some on the back) to register   (line up) is not for the amateur.
> My two girls are very good but even then we do not get 100% yeild.

Oh, this reminds me of the first task I was assigned in my first job, as a teenager in the 70s.
Local electronics engineering & manufacturing company with a contract to produce parts of the microwave-network remote control & monitoring system for the provincial hydro-electric utility.

I was presented with photo-developed silk-screens stretched onto wood frames, the hinged framework that holds the screen and panels in alignment, stacks of lucite and painted-steel rack panels, the goopy paint, and the squeegee/wiper that you run along the screen to wipe the paint thru the screen and onto the panels, and given a rudimentary tutorial in what to do.

It wasn't complex in that it was single-color/one-screen artwork, but the lettering was very fine, about the type-size of newsprint. It was near-impossible to get a smudge-free print. When the screen was sitting such that it contacted the panel the ink would wick between the panel and fabric screen, and blur the print. I improvised and adjusted the frame so the screen would sit a fraction above the panel and be pressed into contact as the squeegee passed over. But the screens were so large that they would inherently be stretched and pulled as the squeegee passed over, so again, smudged print. Every panel seemed to take multiple attempts. Being summer, while I was cleaning the panel of the fouled print with some noxious solvent, the paint would dry in the screen, so now the screen would have to be cleaned as well.

Maybe more experience would have helped but my impression was they wanted to do too fine a resolution for the screen size (panels around 19" square). 

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