There are keys (push buttons) on the front panel of an avionics device that fits inside the aircraft cockpit. I need to know the material of which those key-tops are made from.

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I can guess the material is some type of clear transparent plastic and then its painted with black color. The text on it is un-painted key surface. There is green light under the keys (buttons). That green light glows the text (due to transparent plastic) on the key-top as green in color.

This cockpit device is from a very old aircraft model of 1950's so we can say it is not using any modern high performance thermoplastic or composite material. How can I best identify the material of these key-tops?

Do i need to delete this post from here as now I have posted it here also?

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    $\begingroup$ This question will fare better in the Aviation StackExchange. $\endgroup$ – kamran Sep 15 '20 at 7:45
  • $\begingroup$ Seems unlikely to be painted - more likely a two-shot moulding. Paint would have shown signs of wear in 70 years! $\endgroup$ – Jonathan R Swift Sep 15 '20 at 11:24
  • $\begingroup$ Do you have a sample of material that you are able to destroy? There’s processes for determining what plastic something is, but it usually involves burning to observe the flame and smell! $\endgroup$ – Jonathan R Swift Sep 16 '20 at 7:18

Have you heard of double shot moulding? In this process, the white is a separate molding that is actually embedded behind the black key. This would not show wear and might narrow down your material choices. Nowadays this is done with ABS or PBT. I don't know about your application though.

  • $\begingroup$ A common example of double-shot moulding you'll be familiar with is soft-grip toothbrush handles. $\endgroup$ – Transistor Sep 15 '20 at 21:38
  • $\begingroup$ @DKNguyen I need to glow the text on button using the LED light that is situated under the button body. How will the double-shot molding work in this case? Do you mean the white color text on the button-top will be the second-material used in the injection on top of the base black button body material? $\endgroup$ – scico111 Sep 17 '20 at 10:01
  • $\begingroup$ @scico111 Two materials, but the white frame is actually an insert that enters from underneath. Google double shot button images. $\endgroup$ – DKNguyen Sep 17 '20 at 13:28
  • $\begingroup$ encrypted-tbn0.gstatic.com/… $\endgroup$ – DKNguyen Sep 17 '20 at 13:31

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