good way to whiten yellowed ABS?

[jshel2000]

I've heard of the use of everything from peroxide gel/cream, just soaking the object in hydrogen peroxide, and even the use of bleach. Any other ways that can un-yellow ABS for a decent amount of time (like a year or so) without weakening the plastic or (with keycaps) without fade the lettering?

I ask because I got a free focus fk-2001 that did this weird thing where the left three quarters or so of the board is so yellowed it's almost tan like wood or something but the right quarter looks brand new. Looks kind of off. I'd be fine if it were one constant color, but that gradient kind of appearance makes it look like it was burned or something when it clearly wasn't.

I've heard that things like retro bright don't last forever, but does anything really? It will still re-yellow eventually, but as long as it doesn't turn yellow again in like a week I'll be fine, and as long as it doesn't make the plastic as brittle as glass.

[Findecanor]

Hydrogen peroxide (H₂O₂) is the active chemical in Retr0bright, whatever recipe you use.
It is a kind of bleach. You should not use chlorine-based bleach because that its a completely different chemical.

H₂O₂ does need to be activated, however. Either:
1) Heat: Between 50°C and 80°C. It might not be that easy to keep the temperature within that range, and if it gets too warm the plastic will warp. Some recipes contain a bleaching detergent such as OxyClean that contains TAED which helps H₂O₂ work in lower temperatures — but with the drawback that the detergent foams.
2) UV radiation, which is part of sunlight (the rays that that give you a sun-burn). The most common method is to leave it in the sun.
Larger parts such as keyboard and computer enclosures are often coated in peroxide gel/cream, wrapped in cling film and left in the sun to "develop".

Retr0bright should not bleach the letters, only return the plastic to its original colour. Only if you leave it for too long will you get white marks in the plastic.
You could of course get streaks if you apply gel or cream too unevenly.

It could perhaps weaken the plastic, but plastic weakens with age anyway... so I don't think anyone can say how much is due to H₂O₂, really.

And BTW. Congrats on the keyboard!

[jshel2000]

Hydrogen peroxide (H₂O₂) is the active chemical in Retr0bright, whatever recipe you use.
It is a kind of bleach. You should not use chlorine-based bleach because that its a completely different chemical.

H₂O₂ does need to be activated, however. Either:
1) Heat: Between 50°C and 80°C. It might not be that easy to keep the temperature within that range, and if it gets too warm the plastic will warp. Some recipes contain a bleaching detergent such as OxyClean that contains TAED which helps H₂O₂ work in lower temperatures — but with the drawback that the detergent foams.
2) UV radiation, which is part of sunlight (the rays that that give you a sun-burn). The most common method is to leave it in the sun.
Larger parts such as keyboard and computer enclosures are often coated in peroxide gel/cream, wrapped in cling film and left in the sun to "develop".

Retr0bright should not bleach the letters, only return the plastic to its original colour. Only if you leave it for too long will you get white marks in the plastic.
You could of course get streaks if you apply gel or cream too unevenly.

It could perhaps weaken the plastic, but plastic weakens with age anyway... so I don't think anyone can say how much is due to H₂O₂, really.

And BTW. Congrats on the keyboard!

I didn't know that peroxide was a bleaching agent. Learn something new everyday. Also learn how bad american high school chemistry is as a class. But yeah I meant chlorine bleach. I heard of people using that and it made me cringe.

But thanks! The dust cover is in great condition, though it is actually tinted brown instead of gray, but I'm not sure if there is a way to fix that like with yellow abs. But, because of the dust cover and (for better or worse) very low weight, I'm going to make it my 'portable' keyboard that I take on trips and to school. Lugging around my daily driver, which is a model F, would be a bit of a chore.