Hi Guys,
I'm surprised there is little if any mention of the Retrobright process for plastics.

The site lists a lot if ingredients that aren't likely to be sitting around,
but I had good result with just Vanish (the commercial stain remover) on it's own.

Anyone else tried it for plastic restoration? What about darker colours?
Cheers, Art.

I am pretty sure that it must be this one,
and have a hydrogen peroxide warning under Safety Directions.

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In my experience just about any cleaning detergent that claims "oxy" action will have some apparent affect on yellowed plastic.

There are purists, some of them chemists, who insist that only their own specific pet formula should be used.

There are also people who warn that the effects of Retrobright and similar treatments is temporary, and may in the long run shorten the life of the plastic.

I think the reality is that no two plastics are the same, and no two items of the same plastic have had the same lifetime exposure to light, various ambient gases, chemical stains, heatloads and vibration, all of which can contribute to the decay of the plastic. (A bit like ageing humans, really).

So I think of Retrobright as like hair dye - can be spectacular but always a bit suss.

A good scrub with Napisan or similar will get rid of external greases, give a mild oxidising refresh to the original plastic colour, and not bite too deeply into the chemistry of the plastic. That's what I do, and I have scores of vintage computers..

Maven

Didn't really have a choice short of manufacturing a new dial cover Maven.
It was so bad, even the lamps behind the dial markings might not have been enough to see it!

I understand the need for the recipes that form a paint on gel.
It was pointed out on EAB that you can't really immerse a CRT monitor case in liquid vanish,
so their own "pet formula" would have merit there,
just as if I work up the guts to treat the non-printed side of a plastic dial face.

Depending on the radio, there are several sources of replacement dial covers. If its a reasonably common radio, and it is just the lense thats discoloured you're in luck.

Complete dials are made for some radios as well.

I have used Brasso in the past to polish a dial cover. Its not really effective, but replacements just weren't around 20 years ago.

Post a pic of the radio/dial in question??

In all honesty, the less you muck with plastic the better.

Ben

If you want to polish the non-lettered side of a plastic dial cover, you could try Megular's PLASTX, available in auto spares shops, designed for polishing plastic light lenses. I've used it effectively on a plastic iPod case and screen. You should test on a small area, as not all plastics are compatible. PlasteX won't touch any deep discolouration. For a badly deteriorated perspex dial cover, I replaced with a sturdy polycarbonate, offcut from a sign shop.

Maven

It's my 1931 Airzone, I've already got a thread about it,
but the before and after of the dial face cover:


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The haze in the cover isn't the Vanish's fault,
it already has what looks like a lot of fine cracks through it.

The actual dial face isn't all that bad, just very brittle. It's colour does vary a bit:

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I got a copy of that Radio Waves magazine, and there's a guy that makes them.
Hopefully he will have one of mine.

A lot of perspex dials develop those hairline cracks as they age. It's irreversible, as is the discolouration. Some purists think it retains authenticity, I prefer restoration if possible.

If you can't find a replacement to buy, you can make your own with a scanner, photoshop, and visit to a sign-printing shop to print it on perspex or a modern polycarbonate. I've done that for one of mine, and shared the re-made image with others on this forum.

Maven

I don't know what colour it's supposed to be.
It couldn't have been totally clear or you'd see radio guts through it.
Maybe it was just a bit yellow.

One advantage of photoshop (or Gimp, or whatever) is that you can make copies of your dial image with backgrounds of various hues and opacities and print them on cheap transparency sheets to see how they look in situ, then go for a structural print when you are satisfied.

Am I right that the dial face is translucent and backlit, and there is a separate clear transparent dial cover? If the dial face is not backlit but lit from the side, then your task is much easier because you won't need professional printing on plastic. A decent inkjet would do, perhaps with a slightly matte lamination if you need some diffusion of light source coming from sides.

Maven

Yes, it's a dial face and separate cover, and the dial face is backlit.
I'm inclined to see how the yellowed original dial face looks if I get a brand spanking new cover.
That might happen.. the NSW guy advertising in Air Waves has my model.

This guy Richard in NSW did quite alright.
The only thing he's lacking is a guillotine to cut the final cover
out properly, but since I got more material, rather than less, it's ok.