TOPIC:

I have had very good results using 6% hydrogen peroxide in direct sunlight in an open glass container lined on the outside with tin foil, to refect more sunlight

I have done this mainly on yellowed wild willy wheels (I read somewhere they are nylon ?)

Clean first using denatured alchohol (methylated spirits)

I left them outside for 2 days in bright sunshine (Australian summer)

You need to top up the peroxide now and again due to evaporation

Flip the wheels over every so often (with a chopstick) and shake off the bubbles

Watch out for splashing, I got a drop on my finger, it is like a burn

Let soak in water for a while to get rid of any residue

So far no ill effects, they look and feel great

I am considering clearcoating (TS13) or dipping in 'future' acrylic floor wax - (an old slot car trick), to prevent further uv yellowing ?

Welcome and thanks for that.
I think the coating would have to be UV resistant 'cause that's what seems to be the catalyst for the bromine reaction when it's not in peroxide... but I reckon it should work then.

Edou
thanks for the welcome
future is fantastic stuff, read this article
www.swannysmode...uture.html
thinking of dipping my willy in it, snarf

Wild Willy M38 wheels are definately ABS - been there, fixed them...

As for dipping yer willy in it, er, I'd rather not thanks

Thanks terragni ... but I can't help thinking climatic differences are going to be a problem here. I think the last day here with properly bright sunshine was in 2008

And as for topping up due to evaporation ... I think what would be needed here would be a cover to stop it filling up with rainwater

eddrick wrote:

Bromine? Nice, skin cancer all round then....

As for UV reacting with anything, what?! UV is an electromagnetic wave, it's not a chemical.... It's behaving like a low energy microwave on the process, introducing energy, exciting electrons etc

Another thought is that there could be some ion exchanging going on, not really sure as I thought Bromine formed -ve ions. Maybe the end result is H2Br + O2 gas or something.

Yes, the UV is not reacting directly with the plastic - it is providing energy to facilitate the reaction.
The science is explained quite well on the Retrobright page ("The Science Bit") and confirms that "H2Br + O2 gas or something" is exactly what's going on.

Laquers and waxes would stop the initial yellowing, even if they are not UV proof, by preventing oxygen molecules in air reaching the plastic and reacting with the Bromine free radicals.

Jonny wrote:

Thanks terragni ... but I can't help thinking climatic differences are going to be a problem here. I think the last day here with properly bright sunshine was in 2008

And as for topping up due to evaporation ... I think what would be needed here would be a cover to stop it filling up with rainwater

he he

Actually Sydney gets more rainfall than London belive it or not 1200 mm vs 850 mm per year
I guess we get it in one go

Maybe try a uv lamp in a well ventilated covered area ?

Seems counterintuitive to use uv to remove the yellowing caused by uv, but it works a treat

Yeah, don't seal the container or you'll end up with a high concentration of oxygen gas to get rid of safely - pure oxygen can react violently with pretty much anything that will burn, particularly oils & solvents.

I might be just being a bit of a pussy here, but I really don't like the idea of "the unprepared" messing about with peroxide, it's akin to searching for a gas leak with a candle

Jonny wrote:

Thanks terragni ... but I can't help thinking climatic differences are going to be a problem here. I think the last day here with properly bright sunshine was in 2008

And as for topping up due to evaporation ... I think what would be needed here would be a cover to stop it filling up with rainwater

Jonny

Did you have a go at peroxiding ?
Here is a pic of my willy wheels after restoration and peroxiding
Pity I have no before pics to show you the state I got them in



I am soaking the tires in glycerol as per your article as I type this

You can always post your wheels to Aus and I can peroxide them for you under the antipodean sun


Terragni

I haven't even ordered the stuff yet - after 1/2 a day of spring, we seem to have gone back to very late autumn here