Re: Retr0bright

>Hmm.. the Retr0bright site says about 40 Vol, which translates somehow into 
>12%. And warns about stronger ones too. So you say that 6% worked fine. I 
>bought a 35%, which I plan on dilluting appropriately.

The site mentions 6% also (some of the variants). Most probably with 12% you 
can get faster result but I would rather go for a weaker one. You have to be 
here patient. My C128 case needed about 1 day (2x half a day) to whiten. 
Don't forget to mask the label with a tape. Maybe it would not hurt it but 
be on the safe side.

>I see - so the black light UVA was just enough, right?

I have investigated it on the internet and somewhere they said UVA is 
needed. In my case it worked well. They keys whitened really fast.  For the 
C128 case I did not use the lamp because it would not light all sides of the 
case and I had a feeling that the sun makes better work here.

>And how - both of you guys - prepared the mixture? In a blender or? I 
>really would not like to spill such corrosive agent around the house if 
>there is whatever mishap or slight leak somewhere during the preparation.

I have prepared it in the basement and did not use blender. Just a plastic 
box and a wooden stick (+eye protection glass). I have diluted a 30% H2O2 to 
6%, then added the xantan and glicerin. After stirring it I added the Oxi. 
It was not a slow procedure, did not have to stir it for hours. Dissolving 
the xantan took the longest.
Preparing the liquid version is even easier. The only problem is that if you 
put too much Oxi in it then a lots of foam formalizes. There is no need for 
much Oxi!


Istvan


-----Original Message----- 
From: silverdr@wfmh.org.pl
Sent: Sunday, October 07, 2012 11:57 PM
To: cbm-hackers@musoftware.de
Subject: Re: Retr0bright

On 2012-10-07, at 22:36, Justin wrote:

> I did it the first time on an overcast day, and it doesn't take a lot of 
> UV to catalyze the reaction, so I wouldn't worry too much about coming up 
> with an intense source.  If you have a place you can leave them outside on 
> a day that it is not going to rain, you'll be fine.  Since then I've used 
> it to clean up all kinds of yellow plastics in not so great fall and 
> winter sunlight, control knobs on my hot tub, etc.  I think you're 
> over-thinking the UV part.

Might be. I never tried it before but I was lead to believe that the UV is a 
critical factor of the successful process. Good to know that it worked also 
in overcast conditions.


On 2012-10-07, at 22:42, Hegedűs István wrote:

> I have used it on a C128. The case I have done with the gel (xantan 
> gum,glycerin,h2o2 and oxi). Very important is not to use stronger than 6%. 
> Someone mentiones 3% which is even safer but slower.

Hmm.. the Retr0bright site says about 40 Vol, which translates somehow into 
12%. And warns about stronger ones too. So you say that 6% worked fine. I 
bought a 35%, which I plan on dilluting appropriately.

> I have used the sun as UV source and applied a foil on it not to dry (the 
> foil helps a lot!). If the gel dries then you will have white areas where 
> the h2o2 becomes stronger so be careful! It is very important not to let 
> it dry out (reapply gel every hour or more often) ! My result is very 
> good.
> Because of this drying problem the keys must be whitened only with the 
> liquid version and using UV bulb. Otherwise the letters can fade. I have 
> an UVA bulb (black 20W energy saver) and it works fine.

I see - so the black light UVA was just enough, right?

> When you whiten the keys you have to use a transparent box in which you 
> have the liquid and the bulb lights it from the bottom. This is needed 
> because the keys will face down when you put them in the liquid.


And how - both of you guys - prepared the mixture? In a blender or? I really 
would not like to spill such corrosive agent around the house if there is 
whatever mishap or slight leak somewhere during the preparation.

-- 
SD!
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