Removing yellowing from Amigas with peroxide

[dJOS]

None of my stuff has turned yellow again, despite living in Australia.

[Mr B]

Considering how different the batches of plastic were, it's no shocker that people have different experiences. I got lucky, and my A1200isn't yellowing at all. Bought a "spare" empty case, if i ever want to return it to original, and it is now what, 10 years old, with so far no signs of changing either.

[ReadOnlyCat]

Originally Posted by dJOS

Indeed, I'll be using it in future.

Be careful with the Peroxide and heat combination though, Peroxide is a nasty corrosive and explosive chemical and heat makes it even more potent.

Use eye protective goggles and gloves at all times when manipulating peroxide solutions as well as some cold water at hand and towel in case you spill some over yourself.

Originally Posted by RiotRetroGaming

I get no problems using my method:

[ Show youtube player ]

Nice.
The 8 Bit guy (shown in a previous video on this thread) uses a similar method with good results indeed.

As for the tingling and yellowing that is normal for peroxide water, even at 0.03% in volume. This is used as an antiseptic and will sting if it can find its way into the skin. The effects are temporary and will reverse in a matter of hours but as you said, using gloves is recommended.

Note though that with higher temperatures and concentrations this effect becomes much more dangerous as peroxide is a very potent chemical (corrosive and explosive).

Another thing: the designation "12 volumes" is misleading, this is actually not 12% peroxide by volume but rather a consumer friendly way to designate under about 5% of peroxide by volume (I do not recall the exact amount).
Getting 12% peroxide on your skin would harm you badly.

Originally Posted by dJOS

None of my stuff has turned yellow again, despite living in Australia.

Did you try exposing some of your equipment to the sun (even if partially) to measure any yellowing or did you just avoid exposure altogether?
I am asking because it would be interesting to know what are the factors which prevent-or-favorize re-yellowing in order to avoid it in a systematic way.

[dJOS]

Originally Posted by ReadOnlyCat

Did you try exposing some of your equipment to the sun (even if partially) to measure any yellowing or did you just avoid exposure altogether?
I am asking because it would be interesting to know what are the factors which prevent-or-favorize re-yellowing in order to avoid it in a systematic way.

My Study has a big window in it that only has the blind pulled down when it's above 30c.

[Retrofan]

Come on, I've seen that it doesn't keep white as original if it was very yellowish after a year.

Of course if it isn't so yellow then it will keep white for a longer time.

Also, if you apply the peroxide for a second or a third time, it seems that it will stay white for a longer time. That's my opinion and what I've seen.

[Mr B]

Originally Posted by ReadOnlyCat

Getting 12% peroxide on your skin would harm you badly.

I would have to disagree. I used 30% hydrogen-peroxide to make (quite illegal) explosive, so i had it... available. Used it to clean all sorts of things for the aquarium, and occasionally that meant i got it on my skin. If you notice, and rinse it of straight away, nothing happens. If you don't notice, and rinse it of first after you get a slight burning sensation, you end up with a red spot, which turns white over a couple of hours, and tends to itch. (like a bitch) Goes away after a few days, and i simply used a moisturizing hydro-cortisone cream, to make it go away immediately.
That said... I don't suggest making explosives, nor washing your hands with peroxides. The first ended up with me getting some plastic shrapnel stuck in various body parts, and the second... as i said... itch. The itch was a bitch. So cheating to the point where you no longer feel it was my way of dealing with it, but ideally, just don't get exposed.
Oh yeah... The first also managed to get me in to some trouble with the law. For some reason they don't like it when you make primary explosives, and use it for fire-crackers.
Party poopers.

[Supamax]

Originally Posted by Mr B

I used 30% hydrogen-peroxide [...] after you get a slight burning sensation, you end up with a red spot, which turns white over a couple of hours, and tends to itch. (like a bitch) Goes away after a few days, and i simply used a moisturizing hydro-cortisone cream, to make it go away immediately.

Based on the effects you described, I would say you definitely got a burn...

That said... I don't suggest making explosives, nor washing your hands with peroxides. The first ended up with me getting some plastic shrapnel stuck in various body parts

OUCH!!!

[Mr B]

Originally Posted by Supamax

Based on the effects you described, I would say you definitely got a burn...

I wouldn't call it a burn. It tries to oxidize the skin, and in doing so, bleaches it, and irritates it. The later makes it red, i suppose from blood flow to the skin, and when it figures out that the irritant is washed of, it slowly turns white. You don't get blisters, dead skin falling of, and so on. Definitely not anything along these lines:

Originally Posted by ReadOnlyCat

Getting 12% peroxide on your skin would harm you badly.

12% hydrogen-peroxide is used on hair, and hence the scalp (skin) regularly. Over exposure bleaches the skin, and causes itching. 30-35% stuff wont eat your skin for lunch, and then try and melt the fat tissue under to sludge.

Again. I REALLY suggest that people are careful, i mean, there is a reason the hairdresser puts a rubber cap on the head of someone getting 12% strength peroxide in the hair, and uses latex gloves, but getting it on you will cause a minor issue, a annoyance, not major harm.

Originally Posted by Supamax

OUCH!!!

Hey... I got two pickup lines out of my experiences with... um... improvised explosives. "Hey, you wanna feel my plastic shrapnel?" and "Do you know anybody else who blew up a cop in a bomb suit, wrecked two cars, and still purs like a kitten when a cute girl gives him a hug?" (Funny tho.. Both works a lot better then you might expect.)

No worries. The cop made it out just fine. It was a "bomb disposal tech" who managed to make a REALLY stupid mistake. He fessed up to it at my day in court, so i suppose i'm the only guy around that did that *points above* and got of with having to see a parole officer once a month for a year. No fine, no slap on the wrist. In todays environment they would have called it an act of terrorism, and i'd be locked up for a long time to come. But i swear. I was only making firecrackers. Primary explosives are very... suitable for such activities. Most high explosives wont light of by flame. Primaries will. Sure, they are also shock, static, and friction sensitive, so you pretty much just don't want to handle them. But back then i was young, and immortal. Just like everyone else who just stopped being a teenager.

Sulfuric acid & hydrogen peroxide, 3:1, (98/30%) now that gets nasty. You can still dip your hand in it, and walk calmly over the the sink and rinse it of. Just don't leave anything you like in it for a prolonged time. Commonly called Piranha solution, or Piranha etch. It eats pretty much all organic material, and oxidizes metals like it had been invented for it.

Anyway, i guess this is a bit to far of topic. 12% hydrogen peroxide isn't going to hurt you, it will just teach you to use safetygear the next time. Use a moisturizing cream if you screw up badly, no reason to be scared.

[ReadOnlyCat]

Originally Posted by Mr B

12% hydrogen-peroxide is used on hair, and hence the scalp (skin) regularly. Over exposure bleaches the skin, and causes itching. 30-35% stuff wont eat your skin for lunch, and then try and melt the fat tissue under to sludge.

Again. I REALLY suggest that people are careful, i mean, there is a reason the hairdresser puts a rubber cap on the head of someone getting 12% strength peroxide in the hair, and uses latex gloves, but getting it on you will cause a minor issue, a annoyance, not major harm.
[...]
12% hydrogen peroxide isn't going to hurt you, it will just teach you to use safetygear the next time. Use a moisturizing cream if you screw up badly, no reason to be scared.

Ok, I should have phrased that better.

It won’t harm you in most cases but safety is not a matter of handling most cases but of making sure the worst cases are handled.

Even 12% peroxide has the potential to hurt you if you have open scratches on your skin or if you get some in your eyes, especially if it is heated at 60C. The burn of the heat plus the peroxide is a nasty combination.

Regardless of what the actual exact damages can be the message I want to convey is “wear goggles, wear gloves and be careful and prepared” and we seem to agree on this one.

[Mr B]

If you get 12% hydrogen-peroxide in a open wound... Well, now it's sterile at least. But yeah, i suppose that would hurt like a mother tru... Bia... Um. Hurt like... hurt like.. I dunno. Trying to come up with something not that offensive, yet forceful enough, and failing. Anyway, yes. We are in agreement. Chemical play requires certain safety measures, if for no other reasons then creating good secure habits.
A mate of mine ended up quite sick from barium nitrate due to stupidity. It's used for green in firework compositions, and he had the stupid habit of storing, and eating food in his "workshop". "I keep my sandwiches way over there in a cabinet, and i work over here, it's fine."
Guess it wasn't fine. The circumstances are still somewhat unclear, but he supposedly had been making green stars while snacking on one of those sandwiches, considering him self safe, since he was working with a moistened mix, so, no dust, was wearing gloves, using tools to manipulate the powders, and so on. Ended up quite sick over a weekend. Didn't learn, still keeps sandwiches in the "workshop".

Good safe practices, above all else. Stay safe, live longer, be happy.

I recently cured my ingrown toenail problem with some electrical sidecutters, alcohol, and hydrogen peroxide. The alcohol by mouth was the anaesthetic, and the peroxide used to sterilise the bleeding wound.

It bubbled away nicely and no additional pain whatsoever. Quite the opposite after screaming like a banshee after cutting and ripping/peeling back the whole side of my toenail.

(Peroxide was from my previous retr0bright success, Superdrug Bblonde 30vol, so only 9% and nice and creamy - great for restoring plastics. I wanted 40vol 12% but they had no stock - it worked anyway)

[\\.\]

Originally Posted by ReadOnlyCat

Be careful with the Peroxide and heat combination though, Peroxide is a nasty corrosive and explosive chemical and heat makes it even more potent.

Is not explosive, it is an oxidizer which means that given the right circumstances (as in its powdered form with a suitable fuel source will result in a fast burn, like Aluminium powder is used as an oxidizing agent in rockets.

After watching plenty of people doing retro brighting, there is something that seems to be escaping everyones attention and that is the wrapping process where people use the peroxide gels and lotions, even distribution but also equally important is to not wrap the item in a way that theres even a micron difference as this can have an effect on the process. Sunlight has something to do with it, possibly the heat it gives off helps the chemical reaction... There is another process that uses peroxide and water and heat with no UV light in sight and it brightens the keys no problem however temperature tolerances are such that your in danger of melting your keys.

[Methanoid]

Having seen people suggest Sodium Percarbonate as good source of the peroxide.... I am wondering which generates MORE peroxide (translate the terms into equivalents if anyone can!?!!!)

A) 1 litre of 12% 40 volume creme Peroxide or

B) 1kg of Percabonate which has an active oxygen content 13% and equivalent to 27.5% peroxide?

To be honest I would probably prefer the Percarb as it stores well and can be made up as needed.

[icycool]

wb Meth2.2

You all need to smoke more, this yellowing doesn't come free!
Actually it happens in sealed almost brand new products too, so you work it out

[turrican9]

I have a 1200 case which I have retrobrighted two times now. It seems to start to go yellow again after a year or so. This was a 1200 I bought on ebay a few years ago

Now, I am looking for one of those new 1200 cases when they come in stock again. But is there any point in continuing to retrobright this? Will it go less yellow for each time?

[demolition]

Originally Posted by turrican9

I have a 1200 case which I have retrobrighted two times now. It seems to start to go yellow again after a year or so.



Will it go less yellow for each time?

I think it will re-yellow a bit slower after each time. The things I have treated 5 years ago have also mostly reverted, but they are still not as yellow as they were before - maybe only 75%.

[Supamax]

Originally Posted by demolition

I think it will re-yellow a bit slower after each time. The things I have treated 5 years ago have also mostly reverted, but they are still not as yellow as they were before - maybe only 75%.

Would it be useful to spray on the Amiga some kind of invisible coating in order to not let air/oxigen reach the plastic surface again and begin the yellowing process every time?

[demolition]

Originally Posted by Supamax

Would it be useful to spray on the Amiga some kind of invisible coating in order to not let air/oxigen reach the plastic surface again and begin the yellowing process every time?

Someone tried that by taking two parts where one was sealed and the other was not and then comparing them after a year or so. They had both reyellowed the same amount but the sealed one was now impossible to re-treat.

[Anachronist]

I'd be interested in trying this on my Neo Candy 29 cab that is yellowed.

[Supamax]

Originally Posted by demolition

Someone tried that by taking two parts where one was sealed and the other was not and then comparing them after a year or so. They had both reyellowed the same amount but the sealed one was now impossible to re-treat.