Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Saeid on December 01, 2012, 02:30:42 AM

Title: Removing yellowing from Amiga
Post by: Saeid on December 01, 2012, 02:30:42 AM
Hi all,
 
This question might be already answered. I am definitly want to try bring back my Amiga to life by giving it a shiny look both on its body and keys (A500).
 
Can you recommend any safe procedures? I have read somewhere about using some potentially dangerous chemicals (A mix of H2O2 with some other stuff).
 
Just now, I have immersed the case of my A520 modulator in a mix of water and a houshold cleaner (those whitening stuff to clean bathroom). In the first few hours I didn't notice any change! I will wait and see if it gets any better tommorow morning.
Title: Re: Removing yellowing from Amiga
Post by: CritAnime on December 01, 2012, 02:43:00 AM
I recall someone mentioning that using certain houshold chemicals can cause the plastic to become more brittle. The only thing I have heard that works is the retrobrite mix, which you mentioned uses peroxide.
Title: Re: Removing yellowing from Amiga
Post by: Lurch on December 01, 2012, 04:13:59 AM
B Blonde Cream Peroxide 12% 40VOL

http://www.superdrug.com/hair-colourants/b-blonde-cream-peroxide-12-40vol/invt/42293/

Carefully cover everything that is yellow and plenty of it. Being a cream it sticks really well.

The key is to get an even covering over everything as you may end up with streaking.

You then leave it outside in the sun, longer you leave it the whiter it gets.

I found that it dries out quickly though so make sure to glad wrap (cling film) pulled gently over the amiga so it forms a hot house.

Make sure it doesn't disturb the cream though.
Title: Re: Removing yellowing from Amiga
Post by: Lurch on December 01, 2012, 04:14:48 AM
Oh and it has to be 12% or higher as it wont be strong enough if it's less :-)
Title: Re: Removing yellowing from Amiga
Post by: danbeaver on December 01, 2012, 04:33:28 AM
You need an oxidizing agent in a base that keeps it in contact with the plastic and is prevented from drying out. To quicken the process UV light (Sunlight or black light) is used.

One of the easiest agents to obtain is indeed hydrogen peroxide; less than 12% (in hair products this is 40 volume) seems to take too long: 15% oxidizes skin; 30% can launch a V2 rocket and explode. A thickened 12% peroxide cream is found in the UK as "B Blonde."  In the US Redkin makes one. This precludes the mixing as in Retr0brite. It does need to be prevented from drying out as in plastic wrap (or reapplication every 15 minutes -- that was not my recommendation).  Left in sunlight for anywhere from 3 to 12 hours depending on how much it needs. Some folks use black light at night or just leave it longer. The crucial issue is checking on it at regular intervals. Over oxidation will lead to brittle plastic. After you are happy with the color, rinse well. Temporarily you can coat it with a UV repellant like Armor All; long term polyurethane will work. Untreated it will reyellow in a few months as the Bromine redistributes itself.

Caveat: Clean every bit of dirt off the plastic before treatment or you will be unhappy with the results -- like cleaning your bathroom tile and leaving the grout filthy black.

There are tomes on this subject. An informed consumer is a less nasty one.
Title: Re: Removing yellowing from Amiga
Post by: freqmax on December 01, 2012, 06:01:19 AM
Tip: Retr0bright (https://en.wikipedia.org/wiki/Retr0bright)
Title: Re: Removing yellowing from Amiga
Post by: Lurch on December 01, 2012, 06:38:50 AM
I found the Cream Peroxide 12% 40VOL easier than retrobright. Contains similar ingredients and produces the same result without having to mix anything :-)
Title: Re: Removing yellowing from Amiga
Post by: Marcel21674 on December 01, 2012, 11:02:32 AM
Can you use this for the key's as well, or wil it damage the symbols?
Title: Re: Removing yellowing from Amiga
Post by: Saeid on December 01, 2012, 02:36:22 PM
Quote from: Marcel21674;717051
Can you use this for the key's as well, or wil it damage the symbols?

Oh yeah thats the important question!!! Will this retrobrite thingy remove any printed marks ?!
Title: Re: Removing yellowing from Amiga
Post by: Darrin on December 01, 2012, 03:29:46 PM
Here's a handy guide to whitening your Amiga:

http://crap.forumotion.co.uk/t14-how-to-de-yellow-your-old-computer-cases-

Follow this and you can't go wrong.
Title: Re: Removing yellowing from Amiga
Post by: spirantho on December 01, 2012, 04:03:43 PM
Retrobright is so awesome because it whitens the "white" bits, and leaves the printed bits just fine. It really is very good stuff.
Title: Re: Removing yellowing from Amiga
Post by: danbeaver on December 01, 2012, 04:17:06 PM
Quote from: spirantho;717081
Retrobright is so awesome because it whitens the "white" bits, and leaves the printed bits just fine. It really is very good stuff.


I.E., yes it is safe to use on keys.
Title: Re: Removing yellowing from Amiga
Post by: freqmax on December 01, 2012, 04:22:51 PM
Buy some sacrificable keyboard and chassi to test on..
Title: Re: Removing yellowing from Amiga
Post by: hishamk on December 01, 2012, 07:19:38 PM
hyrdrogen peroxide retrobriting is NOT safe on *SOME* keyboard key letterings!

Granted, most Amiga keyboards are fine (my experience: A1000, A2000). You could seriously bleed out/mush the lettering on Amiga 3000 keyboards (again, my personal experience) (possibly 4000 as well?), so watch out!
Title: Re: Removing yellowing from Amiga
Post by: Retrofan on December 01, 2012, 09:38:36 PM
Quote from: danbeaver;717085
I.E., yes it is safe to use on keys.


But not in Commodore 64 front keys simbols, they fade away, I know.
Title: Re: Removing yellowing from Amiga
Post by: bitman on December 01, 2012, 10:21:00 PM
Please also have a look at the retr0bright support thread at amibay (might need an account to view):

http://www.amibay.com/showthread.php?t=1480

Here's a lot of advices and experiences..