Due to the break down of the chemical bonds in the plastic. You might find that items that have gone through the retr0brite process will return to yellow over time.
The only method I am presently aware of that prevents this. It's through sealing the plastic with a clear plastic spray. This starves the plastic of oxygen and prevents the unstable chemical chains from latching on to oxygen atoms and beginning the yellowing process all over again. I can say this suits work as I've done it on multiple Commodore Amiga's. That suffered some pretty awful yellowing. James On Sat, 23 Oct 2021, 4:14 pm Justin Poirier, <[email protected]> wrote: > I’m glad to hear that it worked! Thank you for letting us know. So often, > we never know whether our advice was used or successful, so thank you for > taking the time to give feedback! > > —Justin > > > On Oct 23, 2021, at 10:37 AM, Jamil Alioui < > [email protected]> wrote: > > > > Hi, > > > > Thanks to Justin and Jeff for their valuable advice and references. > > > > I did the procedure with the hair bleach gel and indeed, the result is > wonderful. > > > > Thanks to Jeff's video, I was also able to understand what happened > during the chemical reaction. > > > > Thanks a lot to both of you: now I have a nice computer to use and I am > less stupid. > > > > Have a great weekend! Best wishes, > > > > Jamil Alioui > > > > Le 21.10.2021 à 15:28, Jeffrey Birt a écrit : > >> Hi, > >> > >> While 'Retr0Brite', i.e. using hydrogen peroxide to whiten plastic is a > bleaching process other types of bleach do not work the same. Bleaching > agents, hydrogen peroxide, chlorine bleach, etc. do not work exactly the > same so can't be interchanged for this use case. > >> > >> If you want to learn all about the process from where the color comes > from to why the bleaching process works I did a video about that: > https://youtu.be/YPl356YKcVs . In the video description is a link to a > folder which has a paper that goes along with the video and other resources. > >> > >> Someone has already mentioned obtaining hydrogen peroxide in the form > of hair developer. Indeed, this is usually the least expensive source. You > can also use sodium percarbonate which comes as a powder (it is hydrogen > peroxide and soda ash). Mix the sodium percarbonate with hot water to > dissolve it. The drawback is the soda ash is alkaline and may corrode any > bits of metal given enough time. > >> > >> You can also use 'SunBriting' which is plain old fashioned sun > bleaching. > >> > >> Lots of details in the video and paper. > >> > >> Jeff Birt > >> > >> > >> > >> -----Original Message----- > >> From: M100 <[email protected]> On Behalf Of Jamil > Alioui > >> Sent: Thursday, October 21, 2021 2:37 AM > >> To: [email protected] > >> Subject: [M100] Bleaching of yellowed plastic > >> > >> Hello to all of you, > >> > >> I have a small practical question, which will be my first on this list. > >> I quickly looked in the archives but found nothing about this. I hope > to knock on the right door. > >> > >> What is the best method to whiten the yellowed plastic of a Model 100 > without damaging the screen or sanding (=smoothing) the relief or erasing > the inscriptions? I found several possibilities on the internet. > >> One of them is to rub the material with a baking soda paste. But the > one time I tried this, the matte plastic turned shiny. I considered dipping > the case and keyboard keys in household vinegar, but wanted to make sure it > wouldn't affect anything else. I also imagined bathing the yellowed parts > in hydrogen peroxide, but this product is very expensive in Switzerland. > >> > >> Thanks in advance; kind regards, > >> > >> Jamil Alioui > >> (Lausanne, Switzerland) > >> > >> > >> > >
