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Summer, sun and what to do with faded plastics Answered

A lot of us have machine, bikes or such with plastic parts.
And if you are in a country where a UV rating of 10 is a nice spring day already plastics seem to fade away and fail quicker.
Over the years I experimented with a lot of things to either prevent this or to fix it.
If you ever had your old farm basher parked next to the same but sun protect model you almost start crying LOL
Colors look like you painted a white haze over it, white plastics turn yelloish and clear plastic, like on the head lamps of your car go dull and yellow.
You might know what I mean if have really nice and long summers...

So what is the reason for this problem that only seems to affect things in hot and sunny countries?
A lot of plastics are actually fully UV resistant and they won't be harmed or changed.
Great but they still suffer! ?
Not really, it is the softeners, fillers and pigments that suffer most.
In the case of clear plastics it is usually polycarbonate mixes and the culprit is the scratch resistant coating applied on it.
The hard UV rays promote the oxidisation and break down.
So whatever is not resistant to UV will suffer in and mostly on the outside of the plastic.
Problem is that UV penetrates quite deep and as a result we often find that UV protecting agents are added.
Sometimes as a coating, sometimes as a mix throughout.
Older cars often show peeling paint onthe roof or boot lid - the UV protecting in the coating has failed or was just bad.
Back in the old days there was whiteners in washing powder, we had white sheets for the beds and other things and leaving them in the sun to dry actually made them whiter and kept them looking fresh - a positive use for UV bleeching ;)

In terms of real prevention options are almsot fully limited to keeping the xposure as low and short as possible.
There is no clear coating you can apply to keep the UV out that won't affect the looks of the paint job or plastic.
And not all of these coating work on all plastics.
One option though is to keep the plastic clean and shiny.
A highly reflective surface will not scatter the sunlight as much throughout the plastic.
Oxidisation is limited as well, especially if you add some polish every now and then.
In a lot of cases though this is either no option or way too time consuming for us to keep it up.
As a result we start to neglect the routing here and there andover they years the plastic ages faster than what it should.

How to fix or restored faded plastic without paying an arm and a leg for specialised products?
White is always nice and if you have a washing machine or fridge close enough to a window you might have noticed over the years that the plastic parts now appear a bit darker or slightly yellow, often just on one side of the thing...
Old electronics, like Gameboys are doing this too.
Red is my other favourite as like black it produces a white haze easy.
Either way the solution is pretty much the same: reduce the oxidisation by oxidising it more ;)
Whatever is really oxidised in a bad way changed the color instead of just breaking dow the pigments.
UV does this...
On the other hand hydrogen peroxide bleeches and breaks down stains....
As long as parts are small enough it is quite easy to put them in a zip lock bag to submerge them for a few hours or over night in hydrogen peroxide.
Otherwise use a suitable container and keep turning and moving the parts around every hour or so until all looks even again.
In severe cases and if the plastic permits it you can also add a small amount of diluted hydrochloric acid.
Talking diluted! So that means of a low concentration!
In most cases though a day or two with just hydrogen peroxide will suffice.
Do a little test first though as some plastics might just be caoted and either show no reaction at all or the coating has pigment that break down in the peroxide - I never had this happen to me but I have read reports of it and seen the pics of the results.
When it comes to really big parts, like the spoiler on your car or plastic covers on your bike and boat it can be impossible to submerge them even partially.
In most cases people try to fix these by polishing them until the faded areas are litterally removed.
A much nicer and easier way to cheat is to use a simple car polish that is suitable for plastic parts.
Means it should have no warning on it to keep away for plastic parts ;)
Wearing proper gloves you can add some hydrogen peroxide to a small amount of the polish.
And I mean polish, not the stuff to fix a dull or bad paint - what you would use on a new car...
The trick is that the polishing cleans the surface while the peroxide works on the staining and fading.
You just don't let the stuff dry after applying it and polish the dry stufff of, you keep going wet until your color comes back ;)
After that give it a final polish the normal way with just the polishing compound and no peroxide.

Clear plastic...
If it is just yor headlamps or other smaller parts for a once off it might make sense to go to a auto shop and buy a head lamp polishing kit.
Thing with clear plastics is that only too often they come in shapes or installations that make a full access impossible.
Like your head lamps that you can only reach from the front as they are glued into the assembly.
Another problem is that they are aslo almost always coated with some protective stuff.
If hydrogen peroxide alone does not help here then polishing will always remove some of this coating or even all of it.
If the coating happens to be the culprit of the fading and yellowing then you of course get it all nice and shiny by just polishing the coating off - but you also loose all benefits of the coating.
Some car models have headlamps where just the coating discolors and once removed the plastic start to crack under the exposure from UV and through all the tiny damages it get when driving around.
For things like clear covers over a little display there is the problem as access as you might not be able to remove the window pane, a replacement might be the best option.

Hey! Why all the fuzz? I use just oil and it works perfectly!!
You can find online videos and full tutorials where people show you that just a bit of some oil and polishing it off with a lint free cloth brings all you faded colors back out again.
Don't be fooled just because it works so great!
Take a frosted piece of glass and put some oil on it and it becomes clear enough to see through again.
Even works with very thin paper...
What the oil really deos is to coat all these microscopic imperfections.
And with the light now having a very easy way to get through it won't scatter anymore and the fading appears to be gone.
Once the oil is gone the plastic looks as bad as before, hence the need to use an oil that dries off.
Worst thing is that these oil affect the softeners in the plastic.
In some cases this might be benefitial in most it is really bad though.
Like any other solvent the oil mixes with these softeners and over time they are removed from the plastic, the more you use oil to keep it shine the more brittle you plastic might get.
Once you did that it is next to impossible to remove the oil from within the damaged plastic and only way out i to polish it off after sanding it.
The benefit of seemingly protecting the plastic from dirt and water is short lived as well.
Some old oil you got on it would just wipe off but with the added oil in the plastic it can now penetrate.
And that little black dot becomes hard to get rid of...

Last words of wisdom:
Check the type of plastic before you decide on anything!
Especially when it comes to the black plastic with fibre re-inforcements.
Do a tiny spot test in an area that is not so important before going full scale!
Trust me, nothing is worse than only realising too late you selecting of choice is actually removing the pigments from the plastic - hint: if your cloth tunrs into the same color as your plastic then something is wrong.
Use PPE! Gloves and face shield or at least goggle are a must have when working with hydrogen peroxide or acids.
Even at just 3% the peroxide will bleech your skin quickly and long exposure won't be better either.
Once you got a drop of peroxide in your eye you will never forget the googles, so just wear them right away please ;)
If the fading is due to the breakdown of pigments that give the color like a white haze on red or blue plastic you might still have to polish off that thinnest layer on the surface to remove the fully bleached out layer.
This however is really quickly done and after that the smooth surface will last much longer.
Work clean!! It is of no use to start before you actually fully cleaned the plastic!