White plastics will turn yellow over time. That’s unavoidable. But you can try to slow down this process and even reverse it temporarily!
If you don’t want yellow plastic, you need to avoid heat and UV light. So maybe not keep your white and shiny helmet on a shelf above the radiator in the sun-filled living room?
But even then I can guarantee that yellowing will occure. You wear the armor on troops. You will be exposed to UV radiation, even in cloudy weather. Just accept this.
But don’t dispair, you can fix it!
The most obvious way is to paint it white. That’s what they did with the helmets in the movies. (These helmets were accually moss green!) But it is easy to make mistakes while painting. Visible brush strokes, paint chips and cracks. No thank you.
An easier solution is to use hydrogen peroxide. This is a chemical often used to bleach things. If you’ve ever bleached your hair, your bleeching solution probably had hydrogen peroxide in it.
My armor hasn’t yellowed that much yet, but my helmet looks terrible. It has a large yellow spot on the left side of the dome, and the faceplate looks like it has gotten a sunburn. So I decided to try to fix it.
Hydrogen peroxide is a blank, water-like liquid. You either need to submerge the parts in it, or get it to stick to your parts somehow.
A word of caution: Hydrogen peroxide can cause severe chemical burns. Do not get it on your skin, in your eyes or lungs. WEAR PROTECTION!
I’ve not seen anyone doing the submersion thing with this costume, but a YouTube channel called Odd Experiments describes a way to do this: https://www.youtube.com/watch?v=JX-RJM8MZpU
The most common way I’ve seen is to mix the hydrogen peroxide into someting sticky. A popular recipe for a home-made solution was shared on various bulletin boards and forums back in the earlier days of the Internet. It is called Retr0bright (or Retrobright), and this recipe currently lives on retr0bright.com.
It can be a bit difficult to find some of the ingredients in some areas. Hydrogen peroxide, for instance, might be a restricted chemical where you live. Check with your local pharmasy.
But you can find pre-mixed variants on the market, such as ArmorWhite from Trooperbay.com. This is what I used to whiten my helmet.
It is a fairly straight-forward process. Coat the part you want to whiten with your prefered hydrogen peroxide solution, and then let it sit in UV light (sunlight) for 12 hours. Wash off and repeat if need.
I coated the entire helmet in the stuff, all of the white areas not just where it was yellowing. I probably should have removed the black rubber bands and protected the eye lenses. Luckily I didn’t get any of this stuff in these areas.
Then I placed the helmet outside and let it sit in the sun for the entire day. Every few hours I turned the helmet around, so that the sun would hit the left side and the front, where most of the yellowing had occured.
I’m very pleased with the result. The large ugly yellow spot on the dome is no more. Most of the sunburn on the faceplate has dissappeared. I still see some slight yellow tinting and spots, but it is barely visible.
Another round will probably take care of this. But that will have to wait – I live up north, so we won’t get another full 12 hours of sun for at least six months now.