PDP 8E Panel Paint Chipping - How to seal edges

rod rodsmallwood52 at btinternet.com
Mon Nov 9 17:04:39 CST 2015

      As you all know all my experience is with new reproductions rather 
than old panels.
I don't expect
I have however seen a lot of pictures of peeling panels.

There are two possible ways a panel could have been made.

      1. Holes first - screen print second
      2.  Screen Print first holes second.

In case 2 above you would be cutting the ink layer and exposing the edge 
to attack.

Forty some odd years ago paints and inks would be have been made 
differently to today.
Peeling would indicate the bond between the ink and the surface to which 
it was applied has broken down.
Transparent film might help but it does nothing for the underlying problem.
I think some kind of penetrating liquid that reestablishes the ink/paint 
to plastic adhesion would work.

We have many examples of plastics and polymers  degrading with time:

             Blue rot in DEC Monitors
             Feet on cases turning to a black goo
             Bump stops in hard drives

So I'm not surprised we get problems with old panels.

Rod Smallwood

On 09/11/15 21:09, Todd Goodman wrote:
> * Doug Ingraham <dpi at dustyoldcomputers.com> [151109 15:00]:
>> Depends on why it is peeling.  My glass panel on the Straight 8 was
>> peeling.  I suspect finger oil was what started it and once it started
>> peeling there was no good way to stop it.  I scraped back to the color
>> change line and cleaned the glass and repainted.  That was around 1985 and
>> it has stayed put so far.
>> Your best bet would be to do something similar.  Mask it off and remove the
>> peeling paint back to the mask line.  Prime the surface and then paint with
>> a color that is close.  If it will be exposed to a UV source you might
>> consider overcoating with a UV block type of clear coat.  I think you can
>> get clear coat in a non gloss if that is what you want.
>> You can try nail polish.  The acetone in the polish might dissolve the
>> original paint.  If possible try it first in a place that is not visible.
>> It could make things worse.
>> Good luck!
>> Doug
> I could be wrong but I believe it's nail polish *remover* that contains
> acetone (unless you get one specifically without acetone.)
> I think nail polish has ethyl acetate?
> I've seen pinball restorers generally recommend Krylon Triple Thick
> Clear Glaze and Krylon Acrylic Crystal Clear.  (Check out
> http://www.pinrepair.com/restore/index1.htm#bg)
> Temperature cycles are particularly hard on pinball glass (hot/cold
> cycles because the paint and glass expand and contract at different
> rates.)
> Pinball glass can get a lot of heating too from the lights.
> I don't know how much of an issue that is with a straight 8 or 8E but
> something to keep in mind.
> Todd

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