Removing yellowing from Amigas with peroxide

[chiark]

peroxide = hydrogen peroxide, availble from chemists typically in 3% or 6% concentration. 30% recommended, and maybe available from hairdressers

oxy = vanish oxy powder (tradename of a cleaning product). In the UK, it comes in bright pink containers and is sold in supermarkets, etc.

[AlfaRomeo]

If you could post some photos so I see if could recognise from any supermarket...

[Zetr0]

Originally Posted by AlfaRomeo

If you could post some photos so I see if could recognise from any supermarket...

meh... its a post count

OXY ( contains the ingredient TAED, an accelerant to the process)


anything with (Oxy Action will contain a source of TAED) all though the process doesn't need this, it will speed up reaction and result times emensley.


HH2O


peroxide, or its full name Hydrogen peroxide, can come from many places, like hair saloons /barbers or just about any Hair dying product.

the above is its most common 6% form from the chemist, however you can get (*and will need*) stronger concentration, around 25% or higher.

Dark Light / UV


This is another accelerant to the process, by blasting the component with UV rays we destablize the weak electron bonds of the oxygen atom that is attachted to the bromine atom from the flame retardant chemical in the plastic.

by inducing a pull on that oxygen atom, (surrounding it with hungry Hydrogen atoms) as well as bathing it in UV light this will essentially de-oxidize the plastic to its original colour, or there about's.


I will say this process is ONLY TEMPORY and the component will need to be treated to stop future oxidation.

[AlfaRomeo]

Thanks for the explanation and photos Zetr0 now I will try to find this products on the supermarket

[tonyyeb]

Originally Posted by Merlin

.... and 1/8 teaspoonful per gallon of Oxy.

Ha! That is where I went a bit wrong. About a dessert spoon to 1 litre I did! No wonder it foamed up quite a bit! We were expecting more of a reaction... so we kept adding more! lol!

[DDNI]

Tonyyeb, you also went wrong by hitting your mouse with a sledge hammer

[tonyyeb]

Originally Posted by DDNI

Tonyyeb, you also went wrong by hitting your mouse with a sledge hammer

Lol!

Thankfully some kind Amiga users have sold/sent me a replacement (or three! ooops!) They will come in handy as my A600 didn't come with one, also I now have a spare. Amigakit threw an old second hand one with my last order as well which was very kind as I was mouse-less until then. Cheers Amigakit!

[rkauer]

Originally Posted by AlfaRomeo

Thanks for the explanation and photos Zetr0 now I will try to find this products on the supermarket

@AlfaRomeo: the product is called "água oxigenada" and the oxy thing have a common brand of "Vanish 'poder O2' " on any supermarket.

The peroxide is more easily found on "women cosmetic stores" sort of. It's the very same intended for "blonding" the hair.

[T_hairy_bootson]

Best Hydrogen peroxide I can find on the net in Australia seems to be 19% It comes in one litre or five litre bottles and is sold from pool/spa shops. So you guys are submerging the parts in the stuff you must need a lot more than 473mil depending on the part or are you diluting it with water?

19% Hydrogen Peroxide


We also have Vanish Oxy Action here it is sold under the NapiSan brand name, not sure if it contains TAED though.

NapiSan Vanish Oxy Action

[Merlin]

@ THB

If it says "Oxy Action" it's the right stuff.

Regarding peroxide, you may be able to get it larger quantities at 30% strength if you look around pet supplies for something called "Urine Rescue" (ewww.....)

Lorne of The Vintage Computer Forums found this stuff, it's a lot cheaper too.....

[laser]

I have made lots of experiments recently with h2o2 and I found that the best accelerator is heat...
UV light doesn't works ....I think is a myth

I used a stove which produce hot air as accelerator...and I can guarantee that on 24 hs and 20% h202 bleach totally anything yellowed ...plastics and gums

also I have bleached the keys of some of my remote controls (gum)....keys originally gray but yellowed after some time...and now of course returned to gray

[prart]

but what about those sticker/badge/whatever with "Commodore" and "Axxx" names: do i need to secure it somehow? tape, glue? does this process will wash my beloved "A600HD" name?

[Eclipse]

If you get lots of Hydrogen Peroxide be careful if you live in the UK. Some chemists will report you.

[Dexther]

I need italian to take me a heads

[rkauer]

Originally Posted by prart

but what about those sticker/badge/whatever with "Commodore" and "Axxx" names: do i need to secure it somehow? tape, glue? does this process will wash my beloved "A600HD" name?

Stickers aren't affected. Don't worry.

[Merlin]

Originally Posted by laser

I have made lots of experiments recently with h2o2 and I found that the best accelerator is heat...
UV light doesn't works ....I think is a myth

I used a stove which produce hot air as accelerator...and I can guarantee that on 24 hs and 20% h202 bleach totally anything yellowed ...plastics and gums

also I have bleached the keys of some of my remote controls (gum)....keys originally gray but yellowed after some time...and now of course returned to gray

Sorry dude, Lorne over at Vintage Computer Forums disagrees with your heat theory; he lives in Arizona and heat isn't a problem there. Heat alone doesn't cut it; UV is definitely required.

Read the later posts in this thread:-

http://www.vintage-computer.com/vcfo...light=peroxide

Lorne is working to optimise the process and he has proved to himself that UV is needed, the UV photons destabilise the co-ordinate bond between the oxygen and the Bromine in the flame retardant (the bond isn't strong enough to be a covalent bond, so it has to be shared electrons between the oxygen and the bromine). No UV, the parts only get wet.

Using bleach to remove the yellowing is only replacing Bromine with Chlorine from the sodium hypochlorite in the bleach; Bromine and Chlorine are both Group VII elements (Halogens) and have one free electron space in the outer orbital. The Chlorine is higher in the Halogen series than Bromine and hence displaces Bromine as it is more reactive. Some yellowing will still occur, as Chlorine will share electrons with oxygen atoms in the same way Bromine will, via a co-ordinate bond.

Please feel free to disprove my theories on this, as long as you can provide some kind of logical chemistry argument to back it up.



Merlin

[protek]

I've managed to get whitened results with only 6% solution of H2O2, so it doesn't necessarily have to be the strong stuff.

[Merlin]

Originally Posted by protek

I've managed to get whitened results with only 6% solution of H2O2, so it doesn't necessarily have to be the strong stuff.

I agree; most beauty supplies won't sell stronger than 20%, as above that strength it can burn and damage skin and eyes. A lower strength gives more safety to people and better control of the de-yellowing process at the expense of a little bit more time, I don't feel it's a bad trade off overall.

[tonyyeb]

Anyone know where to a get a cheap, suitable UV lamp in the UK? Mail order / Internet preferable. (Link if possible!)

[Merlin]

Here you go....

http://www.maplin.co.uk/Module.aspx?ModuleNo=33124
http://www.maplin.co.uk/Module.aspx?ModuleNo=24245