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Removing yellowing from plastics - Part 2

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I just used hydrogen peroxide from my local pharmacy at only a 3% strength - It did a phenomenal job - took 6 hours outside in 38 degree temps.

There is no reason that I can see to use such high concentrations of hydrogen peroxide...

This process does produce unbelievaby good results.

Edit - pictures added per Merlin's request below

Before: http://www.flickr.com/photos/34964865@N07/3244960518/
After: http://www.flickr.com/photos/34964865@N07/3244960944/

Materials used: http://www.flickr.com/photos/34964865@N07/3244962958/

I'm working on an HD20 case and my keyboard. I'll post pics too.
 
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@ Lorne

The consensus of opinion between us chemists is that the plastic has been restored to original condition; as Bromine is still present it will still yellow in time.

It shouldn't yellow quicker, as the only catalyst for the degradation is UV light.

The process should work again on a piece that has re-yellowed as Bromine will still react to UV light, although do you really want to wait around for 20 years to prove this?

Just coat it with clear acrylic lacquer and be done with it.....;)

LOL

Edit: Nice job Lumpydog, considering the peroxide was only 3%. I am glad you are impressed; trying it for yourself is the only way to see how well this works. It's quite elegant chemistry under the deceptively primitive skin.
 
@ Lorne / Tezza & all

I see that we are at 160+ posts in this thread; I propose that we get to 200 like the first thread then roll over into thread number three.....:eek:

I never ever expected to get to nearly 400 posts on here about this, it's brilliant....:-D
 
More unreal results at even lesser H202 percentage

More unreal results at even lesser H202 percentage

Here are more examples of de-yellowing that I've done per my prior post in this thread.

Today I put my HD20 case in the H202/Oxy solution and left it outside for 6 hours. Note that I actually used 1/2 water and 1/2 3% Hydrogen Peroxide solution. You can really cut the H202 and STILL get good results.

Case before (you can see the footprint where the Mac used to sit on top): http://www.flickr.com/photos/34964865@N07/3245545696/

Case in the solution (used clear plastic to allow max UV penetration): http://www.flickr.com/photos/34964865@N07/3244719829/

Case outside in the sun (UV): http://www.flickr.com/photos/34964865@N07/3245545344/

Case after: http://www.flickr.com/photos/34964865@N07/3245552112/

Really amazing results... Gets the plastic back to the original color.

I have my keyboard surround in the solution now - sitting in my basement with a UV bulb. Pics forthcoming. I will add them to this post.

Lumpy
 
Wow

Wow

Lornes Pictures of the keyboard in the second post in this thread.. WOW that look's good..

I use 2 scoops of oxyclean mixed into 1 gallon purple power then I add 2 cups of boiling water and grab my girlfreinds electric toothbrush and go too it.

I am going to try your method and see the comparisons...I'll let you see results when I have time to get on that.
 
@patscc

I've done some more research on this and it would appear that the specific PDBE we are dealing with is one called Tetra Bromo Bisphenol A (abbreviated to TBBP-A). TBBP-A is extremely photo sensitive to UV light and can under go selective debromination and further photolytic degradation, ending up as chemicals such as 2,4,6 tribromophenol and Bisphenol A. The half life of TBBP-A can be as low as 2 1/2 hours under UV light (which explains quite a bit when you look at our results). There is a possibility that these get extracted from the surface and end up in the liquid, although I'm not 100% sure about this.

I have a few abstracts and technical papers to trawl through over the next couple of days, after which I can be a bit more specific on the actual mechanism.

If you 'Google' UV photolysis of TBBP-A, there's quite a lot out there if you are having trouble sleeping.....;)
 
A little StyleWriter II restoration. It wasn't too bad, but definitly needed a dip.

Before:
100_4668.jpg


After:
100_6116.jpg


I also finally finished the Mac SE. The last thing to do was the keyboard:

Before:
100_4178.jpg


After:
100_6126.jpg


And here is the final result:

Before:
100_4201.jpg


After
100_6138.jpg
 
Yes, very nice!

Just on that spacebar key. Hard to tell from the photo but did it come out a little streaky or spotty where the de-yellowing was a little inconsistant?

Certainly looks much better than it did though.

Tez
 
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