Amiga.org

Operating System Specific Discussions => Other Operating Systems => Topic started by: danamania on January 24, 2017, 12:10:15 PM

Title: Non-retr0bright de-yellowing.
Post by: danamania on January 24, 2017, 12:10:15 PM
Posting in here because I wasn't sure of the best place, not having been here for a long while.

I've used retr0bright a fair bit on my old Macs, and it does the job. Curiosity about the causes of and fixes of yellowing lead me to leave some plastics out in the sun for a bit, to see if I could induce yellowing (and how quickly it might come on).

Turned out a week and a bit in bright summer sun near completely de-yellows old Mac plastics. That was a surprise.

some pics below:

(http://www.danamania.com/tmp/9_days_sunbrighting_imgur.jpg)
(http://www.danamania.com/tmp/q605_final.jpg)

Manufacturer plastics vary of course, so what works on the typical Mac plastics may give a very different result on those used for Amiga cases, but thought I'd share the idea in case anyone wanted to give it a burl. I've only done a few pieces so far, and I've now packed them away with a reminder to check them every month to see if there's any re-yellowing or even extra-yellowing that's yet to show.

The top case in the pics above I just sat on top of a garden shed for 12 days total. I left it out overnight, and all day during midsummer sun and >30C temps (and a couple of thunderstorms). No other treatment than Lots Of Outside.

Dana
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on January 25, 2017, 07:31:49 PM
Hello there. So you didn't treat the plastic except for blasting it with raw sun light? And this actually reduced yellowing? Sorry if I'm being dumb here (wouldn't be the first time), but that sounds like an April fool. :laughing:
Title: Re: Non-retr0bright de-yellowing.
Post by: nicholas on January 26, 2017, 12:34:33 AM
Sunshine? What is this thing you speak of?

Yours inquisitively from Manchester.
Title: Re: Non-retr0bright de-yellowing.
Post by: danamania on May 17, 2019, 05:43:29 AM
Thought I best followup a couple of years later with my results. I didn't check my Q605 for long-term damage after sunbrighting until recently when some other forums picked up on the technique and I saw a lot of folk putting their machines out in straight sunlight. I dragged the 605 out, and it didn't end well for the poor Quadra.


(http://danamania.com/tmp/605_lightbright_failure.jpg)
Title: Re: Non-retr0bright de-yellowing.
Post by: guest21671 on May 18, 2019, 03:47:23 AM
No need to double post with the same overly large photos
I remember those.  The yellowed back in the day when they were in use and sold
Retrobright and Lightbrighting both achieve deyellowing via the same process. That is heating and bonding bromide with free oxygen then evaporating it from the surface.
I wonder if someone in Australia would be willing or has done the same a you did with an A1200.  At least with that you could get a new case
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 18, 2019, 11:54:09 AM
Sorry about your Quadra case. I suppose now you'd wished you'd either left it alone or sprayed it white.  :(
Title: Re: Non-retr0bright de-yellowing.
Post by: Dynamic_Computing on May 19, 2019, 03:36:23 PM
I have tested the #LightBrighting technique here in Tucson, Arizona over the past few days, and can confirm it does work. Just remember, all things in moderation. If I left it out for a week or two, it would likely weaken and damage the case for sure. But two or three days? The difference is very noticeable on my A500 case and keyboard. I put a coin on the left side, right under the grill, as a control spot. You can see that the case is several shades lighter. So far, the plastic seems to be in the same condition it was before. This is a total of 16-20 hours of sunlight over three days.
(https://www.dropbox.com/s/0blez4bcv1qrqa3/2019-05-15%2007.11.05.jpg?dl=1)
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 20, 2019, 11:46:25 AM
Can you do a follow up post in six months to see if it has reverted somewhat?
Title: Re: Non-retr0bright de-yellowing.
Post by: spudmiga on May 21, 2019, 11:56:15 PM
I tried this with my A500 plus a few days ago, the keyboard in particular had yellowed quite a lot.
Just after a day I could see the keys were less yellowed, without even taking a before photo. I will get it out in the sun again when I get chance (and when we have some sun here in Runcorn).
If it works, I am going to have to employ a security guard in my back garden with all this hardware outside  ;D
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 22, 2019, 10:03:40 AM
I tried this with my A500 plus a few days ago, the keyboard in particular had yellowed quite a lot.
Just after a day I could see the keys were less yellowed, without even taking a before photo. I will get it out in the sun again when I get chance (and when we have some sun here in Runcorn).
If it works, I am going to have to employ a security guard in my back garden with all this hardware outside  ;D

Where do you live? I'll volunteer.  :D
Title: Re: Non-retr0bright de-yellowing.
Post by: vince_6 on May 22, 2019, 10:08:26 PM
The pic in the middle is after 3 hours.
The one at the bottom is after 4 days, 3 hours treatment per day.

(https://i.postimg.cc/4xyBNPfk/Just-sun.jpg)
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 25, 2019, 11:21:40 AM
So let me get this straight - Heavy, pure unfiltered exposure to sun will turn plastics back to white, yet intermittent less powerful sun rays such as shining through windows onto your Amiga desk in the morning will turn them yellow? And too much exposure will actually cause them to go brittle (even if they do turn white)? It's all a bit confusing.
Some plastics turn yellow with age anyway right? I have this gel mousepad and the white plastic has turned yellow about 33% I believe from what it used to be yet it has never had any sunrays on it whatsoever.

So, that mouse for example...it looks much better now. How do you stop it returning yellow again? And from what I've read, any treatment will mean a return of the yellow much sooner than it normally would in getting there in the first place? Also, isn't they yellow just on the surface and not below it? I'm sure it rubs off with a bit of abrasive cleaning but at the cost of ruining the textured surface. I have a very yellowed Archimedes mouse so I do have an interest here.
Title: Re: Non-retr0bright de-yellowing.
Post by: Wizard741 on May 25, 2019, 12:51:06 PM
Toothbrush + Toothpaste = White Color
Title: Re: Non-retr0bright de-yellowing.
Post by: vince_6 on May 25, 2019, 01:38:21 PM
Yellowing is on top on a thin layer.
Also it comes back in a  2-3 months or a year.
I had a usb wifi card that turned yellow and used retrobright.
In 2 month period was like a canari again...
Even an A500 was back to yellow in a box.
Maybe just heat does the job.
Title: Re: Non-retr0bright de-yellowing.
Post by: Wizard741 on May 25, 2019, 02:21:52 PM
Read this (here in Russian, but very useful article) -

https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 26, 2019, 05:49:11 PM
Yellowing is on top on a thin layer.
Also it comes back in a  2-3 months or a year.
I had a usb wifi card that turned yellow and used retrobright.
In 2 month period was like a canari again...
Even an A500 was back to yellow in a box.
Maybe just heat does the job.

So the best bet then is a can of white spray paint?
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 26, 2019, 05:54:55 PM
Toothbrush + Toothpaste = White Color

How long does that last?
Title: Re: Non-retr0bright de-yellowing.
Post by: Wizard741 on May 27, 2019, 05:38:52 PM
Hard to say. It all depends on the plastic and how to use it.

Use polishes. Such tools create an invisible film on the surface - it protects against external influence.
Read more: https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html
Title: Re: Non-retr0bright de-yellowing.
Post by: vince_6 on May 27, 2019, 05:46:28 PM
Also some people use UV sprays, never tried them though.
Title: Re: Non-retr0bright de-yellowing.
Post by: Wizard741 on May 27, 2019, 05:52:14 PM
This is also a good option!
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 27, 2019, 08:41:40 PM
Hard to say. It all depends on the plastic and how to use it.

Use polishes. Such tools create an invisible film on the surface - it protects against external influence.
Read more: https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html

I'll get some Mr Sheen on my existing pastics then. As for old yellowed plastics I'm non the wiser!
Title: Re: Non-retr0bright de-yellowing.
Post by: Wizard741 on May 27, 2019, 09:47:02 PM
Do as you see fit for yourself.
Before that advised - the truth.
Believe it!!!

When you clean the plastic or apply a layer of polish on it, it should be otdedelen from electronica.
Title: Re: Non-retr0bright de-yellowing.
Post by: gertsy on May 29, 2019, 09:24:19 AM
I know AMIGANs who have Retrobrighted and applied a clear matt spray paint and their kit has still yellowed. Results vary.



Title: Re: Non-retr0bright de-yellowing.
Post by: F1Lupo on May 30, 2019, 09:12:16 PM
I keep all my stuff in my mancave which is in a room in the basement of my house so no natural light to be found= problem solved for ever (or as long as my mancave stays put which God willing will be another 30+ years  ;)

Be nice to hear from someone who used the clear spray and put the miggie back to exposed natural light to see if the yellowing came back
Title: Re: Non-retr0bright de-yellowing.
Post by: paul1981 on May 31, 2019, 01:01:14 PM
These UV filter sprays and UV filter house window glass do they really stop plastics yellowing? Or is that you'd still have to keep them out of direct sunlight but that they help reduce the effect?
My first A1200 used to get morning sun for a few years, but even on the left hand side of the computer which was in the shade it still managed to yellow. So I think the sunlight (probably mostly invisible UV) must reflect off the walls and back onto the shaded area...yellowing it. This is where I feel the UV filtering may help.

Mancave? That's definitely the best bet. Of course, lock your Amiga(s) in the cellar and don't give them the light of day!  ;)