I know that restoring yellowed/sunburned plastic cases has been covered before, but this is my first time so I wanted to share (every boy wants to brag about his first time).
I got a Sony TFM-C650W cheap on eBay because the clock was stopped. Seller described the clock as "yellow" and had some crappy pictures that did not reveal the clock's true condition. The clock was originally white, but had been exposed to UV light at a very specific angle for many years. Looking at the clock side of the case there was a vibrant white "shadow" left where the set knob had blocked the light.
A little research revealed that certain older plastics yellow because of instability in the chemical make up of the plastic. ABS plastic has to have brominated flame retardant compounds (BFRs) added to it to prevent it from catching on fire. These BFRs can degrade when exposed to uv light and turn yellow/brown.
Interestingly enough you can reverse the chemical process that causes the yellowing by covering the material in hydrogen peroxide and exposing it to sunlight (uv). Regular drug store hydrogen peroxide is not strong enough, and you need something that will stick to the plastic during treatment. One option is a home made hydrogen peroxide concoction called Retr0bright that many people have used with success on old game consoles. If you are a hardcore DIYer you can get the recipe online and go out and gather the Retr0bright ingredients and mix up a batch, or you can just go to the beauty supply shop and buy Salon Care 40 Volume Creme Developer for $4 instead. Salon Care is a nice sticky high concentration hydrogen peroxide solution.
I disassembled the clock, washed the case with soap and water, then painted the Salon Care on the case and placed it in a ziplock bag. I was only able to get direct sunlight on the case for about 5 hours, so I repeated the process the next day with fresh Salon Care.
I am pretty happy with the results.
Clock side of case before:
Clock side of case after 5 hours:
Clock side of case after 10 hours:
Jeremy
I got a Sony TFM-C650W cheap on eBay because the clock was stopped. Seller described the clock as "yellow" and had some crappy pictures that did not reveal the clock's true condition. The clock was originally white, but had been exposed to UV light at a very specific angle for many years. Looking at the clock side of the case there was a vibrant white "shadow" left where the set knob had blocked the light.
A little research revealed that certain older plastics yellow because of instability in the chemical make up of the plastic. ABS plastic has to have brominated flame retardant compounds (BFRs) added to it to prevent it from catching on fire. These BFRs can degrade when exposed to uv light and turn yellow/brown.
Interestingly enough you can reverse the chemical process that causes the yellowing by covering the material in hydrogen peroxide and exposing it to sunlight (uv). Regular drug store hydrogen peroxide is not strong enough, and you need something that will stick to the plastic during treatment. One option is a home made hydrogen peroxide concoction called Retr0bright that many people have used with success on old game consoles. If you are a hardcore DIYer you can get the recipe online and go out and gather the Retr0bright ingredients and mix up a batch, or you can just go to the beauty supply shop and buy Salon Care 40 Volume Creme Developer for $4 instead. Salon Care is a nice sticky high concentration hydrogen peroxide solution.
I disassembled the clock, washed the case with soap and water, then painted the Salon Care on the case and placed it in a ziplock bag. I was only able to get direct sunlight on the case for about 5 hours, so I repeated the process the next day with fresh Salon Care.
I am pretty happy with the results.
Clock side of case before:
Clock side of case after 5 hours:
Clock side of case after 10 hours:
Jeremy
Comment