Discoloured plastic

[L19MUD]

Is there anyway I can restore this back to former glory? Only thoughts are some compound? 

It is the centre of a light bar and was previously covered with some white vinyl plastic to cover this up (bought used but refurbished a few years ago) but that had also aged. I would prefer to clean the plastic up rather than do that again as it should show up red when the lights inside are turned on towards the rear

The inside is still bright white

[ballcock]

I would try a fine wet and dry to start then a polishing compound works well on polycarb headlights. but try a little spot first.

[Snagger]

I would also suggest simple polishing.

However, there is also the option of flatting it back with progressively finer grades of sanding paper, and then spraying with a lacquer.  The lacquer may reduce the UV reaching the plastic, and should certainly prevent the oxidation.  It’s the combination of UV and oxygen that causes the “corrosion” of plastics, eliminating one of them should work.

[reb78]

Cellulose Thinners perhaps - I had some luck with white uPVC windows that I had splashed creosote on. No way was that just wiping off, but the thinners almost melt the surface and take a thin layer off. Try it on a small area first!

[monkie]

A few more of those beers, then you won't notice it

[L19MUD]

17 minutes ago, monkie said:

A few more of those beers, then you won't notice it

Haha! Was well deserved after a long day in the orifice

 

Thanks all will have a play with the options above. Its 6ft 6 up on the top of the truck so it does not need to be perfect but you can see where stickers have been before

[Nonimouse]

tooth powder, moistened and used as a polish, or in fact any fine abrasive polish, like brasso or chrome cleaner

Edited May 13, 2020 by Nonimouse

[JeffR]

The abrasive polish/cleaner used on glass oven doors (forget the brand) is pretty good, we used it on a polishing mop for headlights.  To get a really fine polish jewellers rouge

[Bowie69]

Lacquer won't protect from UV unfortunately, you could just paint it and be done with it?

[Happyoldgit]

Farecla G3 compound. Sorted.

Or if you don't want to have it lit at any point in the future then just spray it white, or silver etc.

[L19MUD]

51 minutes ago, Bowie69 said:

Lacquer won't protect from UV unfortunately, you could just paint it and be done with it?

Don't be so defeatist 😁

[L19MUD]

46 minutes ago, Happyoldgit said:

Farecla G3 compound. Sorted.

Or if you don't want to have it lit at any point in the future then just spray it white, or silver etc.

It just laughed at the G3, time to break out the wet and dry to take a layer off (or thinners as mentioned above) 

[Happyoldgit]

I used to do a fair bit with lightbars from the States back in the day, I used to buy a product from one of the big suppliers over there that was specially formulated to revive and restore domes that has discoloured, yellowed, tarnished or gone mat through dust and sand abrasion. For the life of me I can't recall what it was called just now but it would work like no other compounds, abrasives or other plastic re-finishers. Clear domes that had been used for years on NYPD or other PD vehicles that had turned beige and mat would restore to virtually new appearance, and what's more they would stay that way too. Some of the segmented Federal Signal domes on the old Aerodynics were stupidly expensive to replace so this stuff was really useful.

So, wet and dry followed by buffing with G3 it is then 😉

[L19MUD]

26 minutes ago, Happyoldgit said:

I used to do a fair bit with lightbars from the States back in the day, I used to buy a product from one of the big suppliers over there that was specially formulated to revive and restore domes that has discoloured, yellowed, tarnished or gone mat through dust and sand abrasion. For the life of me I can't recall what it was called just now but it would work like no other compounds, abrasives or other plastic re-finishers. Clear domes that had been used for years on NYPD or other PD vehicles that had turned beige and mat would restore to virtually new appearance, and what's more they would stay that way too. Some of the segmented Federal Signal domes on the old Aerodynics were stupidly expensive to replace so this stuff was really useful.

So, wet and dry followed by buffing with G3 it is then 😉

How to build excitement and then dissapoint! 😂

[smallfry]

I would have thought G3 is a bit coarse for plastics. Also needs to be used wet to get the best of it.

Screwfix or Toolstation (cant remember which) do a glass polishing kit which works a treat on scratched windscreens. Its very fine and might work ?

[L19MUD]

8 hours ago, smallfry said:

I would have thought G3 is a bit coarse for plastics. Also needs to be used wet to get the best of it.

Screwfix or Toolstation (cant remember which) do a glass polishing kit which works a treat on scratched windscreens. Its very fine and might work ?

The issue is getting rid of the discoloured layer on the top first

[Snagger]

15 hours ago, L19MUD said:

How to build excitement and then dissapoint! 😂

He’s a bit of a tease, isn’t he?  

[Snagger]

13 hours ago, smallfry said:

I would have thought G3 is a bit coarse for plastics. Also needs to be used wet to get the best of it.

Screwfix or Toolstation (cant remember which) do a glass polishing kit which works a treat on scratched windscreens. Its very fine and might work ?

A lot of paints are just a layer of plastic.  But anyway, it works well on plastics.

[landroversforever]

I’ve not done any coloured plastics, but I did the ex’s headlights with the 3m polishing kit and that was night any day compared to various other methods I’d tried in the past. It comes with the backing pad for the drill ad a selection of different grits. All I’d say is keep a squirty bottle of water to hand to keep it wet. 

[Happyoldgit]

...still easier to paint it. Some conventional lightbars, especially the USA stuff like the Federal Signal Jetsonics and Streethawks from the '90's had a black strip painted across the top section of the domes to prevent the sun washing out the flash patterns.