Experiment on how to restore yellow plastic

[rtfoe]

Hi guys,
I don't know if this is the right place as I'm still experimenting after seeing it on Youtube. I'm restoring my yellowed vacformed canopies back to it's original clear form.
The basic ingredients needed for this process is Hydrogen Peroxide and UV light. Apparently the very thing that yellows plastic it UV light and although it was thought that it cannot be saved someone found a way to reverse it by applying hydrogen peroxide with UV light. The video shows it working so I thought I might as well try it.

Since the canopy part is small, all I needed was a small transparent plastic food container and baking foil. I wrapped the container with the foil to act as a reflector of the UV light rays. Fill the container with the hydrogen peroxide solution which I bought from the pharmacy. Try to get one that's pure or at least more than 3% for it to work better. Then I submerged the canopies inside. For UV I used the natural sunlight. I have only started today and so far I see some bit of clearing.



There is a reaction with bubbles forming on the surface. I will leave it for another two days and see what is the outcome and keep my fingers crossed that it works.

Here's the Video on Youtube if you'd like to see they do it. Obviously it's a better set up with UV LED's.

Cheers,
Richard

[Isitme]

Interesting work going on there Richard and thanks for the tutorial - tomorrow take over the world perhaps?
Mike.

[Tim Marlow]

Intriguing! I’m not sure how this works. Most peroxide is used as bleach, so it could simply be a bleaching effect. Chemically H2O2 can act as an oxidiser or as a reducer, dependant upon the chemical conditions present…..so it may be reducing the clear plastic that has oxidised over time…..the UV is most probably a reaction accelerant in either case. Interesting from a chemistry perspective though…...

[Jim R]

Interesting Richard. Waiting for the results in a few days.
Jim

[rtfoe]

Guys it's still early to tell but the videos look quite convincing. Basically larger objects even an air-conditioning cover.
I just want this to work than to try and cast or vacform a new canopy.

Cheers,
Richard

[rtfoe]

You can't rely on weather and it's been rather rainy and the sun being shy. It would be better if one purchases LED UV lighting so uou can get a full 24hr process and maybe speed things up. Also my H Peroxide is only at 3% so may take a little longer.
Just purchased a new batch that is 6% HP.
Fingers crossed for good weather.

Cheers,
Richard

[rtfoe]

Hi, I'm back.

Totally nearly forgot I had the tub outdoors and it suffered overspill from some rain spells but this is the result. Basically there is some significant improvements but not 100%.
You can see the difference of the two on the left, one is the original discolored and the other after the experiment. The piece that's on the far right used to be in the color of the middle piece so there is some improvement but not totally clear.



As the results show, I need a constant source of UV light and more stronger solution of HP. Also the thicker parts need longer periods in the tub.

I will be using the canopy for the Whirlwind as I can live with the very slight tinge of yellow.

Cheers,
Richard

[Jim R]

Looks to have worked reasonably well. With your new hydrogen peroxide and an improvement in the weather I reckon the next lot will be even better.
I hope the new kittys have settled.
Jim

[rtfoe]

Looks to have worked reasonably well. With your new hydrogen peroxide and an improvement in the weather I reckon the next lot will be even better.
I hope the new kittys have settled.
Jim

I need to get myself a UV light source first, Jim for the next lot or these same pieces to go further.

Cheers,
Richard