I expected a deep dive but my goodness, you really dived right in there. Some very interesting results over other experiments I've seen. Thank you for putting what was clearly so much effort into this.
Great work on the video! Vast amount of research work put into, congrats! I had very good results using 12% hydrogen peroxide, mixed with clean water 1:1, keeping yellowed plastics in the warm (50c) bath (in oven) for several hours. Higher temperatures lead to intense bleaching rather than "brightening"
Bromine is a rabbit hole that needs to not be explored, as this has been found not to be the reason for yellowing. As there are plastics that yellow that have 0 bromine content, especially since Bromine is no longer used as a fire retardant in plastics, and yellowing still happens. But the you did finally hit the cause... HEAT. And Heat is also the catalyst to reverse the yellowing. If you vaporbright and raise the temp to 40-45c, I am pretty sure you will see some interesting results.
Bromine does play a (tiny) part but as you say no where near a part as other causes. It probably plays about 1% - I’m planning a follow up to this video soon
A deep rabbit hole indeed. I had a good result with sunbrighting in the garden. I did an experiment with Vanish oxo-action powder, it did nothing. You can really tell that sunbrighting works when you see really old cars that have lived outside all their life. The car might look pink, but it probably started off closer to a deep red.
Nice work! You have put a lot of effort into this and I like your approach! I have always been hesitant with hydrogen peroxyde method, precisely for the lack of control you have... I also made the experience that the absolute worst in terms of yellowing is LED light. We moved appartments and my Amiga 1200 got into a room that is hardly exposed to any sunlight, but frequently to LED lights. Even being in the closet, It yellowed at the side that was pointing towards the gap in the doors! Since it got in this room/closet half a year ago, it yellowed more than in like 5 years prior...
About ozone: I have a 20000mg/h ozone generator. That's massive, when you turn that thing on you get a literally breath-taking whiff of ozone within 2 seconds. It's actually dangerous already. I put the generator and a yellowed case in a big plastic bag, put everything in the spring sun and let it rip for 3 hours. That should have been a nominal concentration of 60 *grams* of ozone in that bag. And it did nothing. Not a bit of a change. Now I think, just like you mentioned, if there would have been some kind of brightening it would have been because of the sun anyway. So, ozone doesn't seem to work, which is a shame, actually, if you have, say, a bottom case with a paper label and don't want to soak it in bleach. If just UVB/sunlight works, this would be a great alternative for those (literally) cases, though.
Yeah agreed. I guess alternate approaches can work on things that ‘traditional’ ones can’t. I’m sure there’s something missing re ozone but I don’t know what it is
As an educated chemist, I always like it when people learn about chemistry through a hobby or related interest. The enthusiasm is completely opposite to what you get in a classroom. Literally 20 minutes ago I was helping my daughter do last-minute revision on electronegativity, UV induced homolytic fission of bromine, and organic chemistry for her A-level exam that will have started, ooh, 10 minutes ago...
It was fun learning it all, and I still don't claim to be even remotly an expert lol. There seems to be so much more in this area that could be researched but I suspect that requires more expensive equipment than I have. Glad you enjoyed the video. I only took chemistry as far as GCSE (and physics to A-Level) so was a real stretch of my knowledge!
I need to find the page someone posted to me, it had a really in depth breakdown of the chemical reactions - something to do with the various acids in the plastic reacting.
I think the reason people equate sunlight to case yellowing is because you often come across a case where there's a clear line of delineation between where part of the plastic sat in direct sunlight (or some kind of light) and the other part wasn't. For example I have an A1000 keyboard thats deeply yellowed but only the front lip where it was obviously exposed to continuous light with the rest of the keyboard safely slipped under the shade of the A1000's keyboard garage. Based on what you're saying here, it seems more likely that while light was the cause of the yellowing, it was actually heat from a light and not the light's UV range that was the cause. I wonder if sitting a machine under an infrared light would accelerate the yellowing.
Would be an interesting test… as long as you don’t melt the plastic! Some plastics maybe different, it’s possible some react to light in different ways. Regarding your keyboard, I assume it was used a great deal over a long period of time, maybe heat from hands contributed. Difficult to know but it absolutely could be a combination of different factors
I remember working at a location in the early 2000s where the receptionist was still using a CRT. The areas facing the window were nearly brown and the rest only slightly yellowed. It was tinted glass but still hotter than hell when the sun was low so I also suspect the heat might be more damaging than the UV.
This is quite an interesting experience. Heat may indeed be a big factor as I’ve had a few pieces becoming extremely yellow when I sent some stuff from Hong Kong to Dubai on a container. After only 30 days these pieces looked dark brown, and they were not exposed to UV.
@@deborahberi3249 Maybe, although UV may still be damaging the plastic in some other non-visible way, like making it more brittle. That would need some more testing though
Really interesting, Especially as I dug out my escom A1200 yesterday thats been left on a bottom shelf, near the radiator and window, but not in direct sunlight, and its become my most yellow amiga, My other a1200 has been in the same room on my desk, and has hardly yellowed. The other slightly interesting thing is the yellowed case, the outside has yellowed but the inside hardly has, even the bottom that would be facing the shelf yellowed. My monitor is has also yellowed being sat there in the same corner.
So, is the answer to put our yellowed plastic into a bowl of titanium dioxide? It seems that that was the one that worked. And what concentration was it?
Well to be honest I haven’t been able to replicate this, and I have been trying. I think I know what caused this, and it was what happened after that failed. I’ll post more when I have a more definite answer
I am currently planning a way to retrobrite my yellowed~white JVC Videosphere CRT with only heat and led strips... I guess this is the safest way for the electronics inside. Still not sure of which wavelenght should work best !! I had retrobrite a lot of NES/SNES console with liquid peroxyde, RGBWW led strips and a "sous vide cooker" for the temperature with great succes but never tried without peroxyde!
@@RobSmithDevInteresting... My friend recently tried to put heat + UV led strips on an ugly yellowed NES cover and it became really good. He also tried the "new" technique of just putting some peroxyde in a tray around the object to retrobrite + UV + heat (retrobrite vapor method) and it also works very very well (faster than UV + heat)...
@@RobSmithDevI'll test with the UV only to begin but the led itself create some heat. Retrobrite is something so fascinating and confusing at the same time. 🤣 I really appreciate the video you made and I hope there will be some updates and experiments soon!
