Removing yellowing from Amigas with peroxide

[gklinger]

Originally Posted by DDNI

Maybe Laser could test and see what happens when you heat it to say >70'C ....

I'd throw in a few quid to help pay for the H2o2.

Jokes aside, has anyone made a video of this yet? I think it would be really interesting and helpful. I'm a little nervous as I'm going to be taking my first crack at this next week. I've got a Commodore VIC-20 case that could stand a good freshening up. Does the process stop when the plastic is removed from the liquid? I'm concerned about going too far.

[tonyyeb]

Hmmm. Nice link but not what I was wanting. I would prefer something that talked more specifically about computer parts. Plus it talks about watering it down and using a florecent tubes...

Chris

[tonyyeb]

Originally Posted by gklinger

has anyone made a video of this yet? I think it would be really interesting and helpful. I'm a little nervous as I'm going to be taking my first crack at this next week.

Yeah that would be great. Someone should do that. A nice little tutorial video.

[DDNI]

Lets list H2O2 products that are available for purchase:

baquashock is a swimming pool cleaner. It is 36% H2O2.

[Merlin]

@ Tonyyeb

OK,

Wear gloves, and protect your eyes if you can, get some goggles from Poundland in the decorating department; you only get one pair of eyes.

You need H2O2 (as strong as you can get). Add 1/4 to 1/2 teaspoonful per gallon of Oxy to the H2O2 and immerse the part to be cleaned. Leave the tank out in the sun or below a UV lamp. Most parts will clean up in six to eight hours.

[tonyyeb]

Any need to weight the stuff down, or floating on the top is ok?

[Merlin]

Plasticene works as long as you attach it to an area that won't be seen. You could also use a fishing weight and line to hold it under the surface. I don't think the fishing line will leave any 'tan lines' on the finished part.

[Merlin]

Sorry DDNI, I have to feed the troll.....

Originally Posted by laser

I don't care about what Lorne says...who is Lorne? a scientist?
I say what I think and what I experimented....
UV light does not help to accelerate

it's not very difficult to understand that heat is the best accelerator because when the liquid is exposed to severe air heat......
that means accelerated with a stove which produces warm air.....the h202 start immediately to bubble......so the reaction is ready fast

bubble = h202 reaction

there's no rapid bubble reaction using any kind of UV light...I tested that

@ Laser

Yes, I am a scientist; I am a former industrial chemist with 25 years experience in oils and petrochemicals, is that enough qualifications for you? Lorne is working the wrinkles out of the process with my help, which you would know if you had bothered to read the thread.

The UV is required as it destabilises the co-ordinate bond formed between the bromine in the flame retardant and the oxygen. This allows the peracetic acid (formed by TAED reacting with peroxide) to detach the oxygen and it gets replaced by a hydrogen, effectively re-capping the polymer chain.

The UV doesn't create bubbles, that is partly due to how much Oxy you add as the TAED in the Oxy catalyses the peroxide.

I suggest you read the TAED Wiki as it goes into more detail as to what I'm talking about. I'm not going to copy and paste chemical formulae into this post as it shouldn't be necessary and puts people to sleep...

In short, I am telling you what works.....if 99 Fahrenheit's worth of heat doesn't work without UV light, doesn't that tell you something....?

The pictures posted of the results speak for themselves.

[tonyyeb]

Well ive started my second attempt:

Before shot with what the colour should be:



Alphabet soup anyone?:



The process is started:



I was told the keys sould start to sink so no need to weigh them down. I will see if this is correct in about 8 hours!

[Merlin]

This is what we want, this is proper science abuse, this isn't the blowing up caravans, Richard Hammond lightweight stuff!!

LOL

[tonyyeb]

Lol. It looks like it is going well 2.5 hours in. Keep giving them a dunking as they have not sunk (yet!) and a quick stir as well.

[Merlin]

Any chance of a 'during' picture, so that we can see ay change in the time spent so far, before we see the final 'after' ones, then?

[tonyyeb]

I will take one at 3 hours (which will be in 20 mins I think)

Do you think the fact the keys are mostly floating will seriously affect the end result?

[tonyyeb]

Before I started:


After three hours:


There is an improvement. Another 3 hours and ill take another picture.

[tonyyeb]

One thing I decided to do at 3 hours was to submerge a key. I dried and added blutac to the bottom of the 'A' key.:



Lots of bubbles have formed on the surface... i'm thinking I should have done this to the rest now. Ill leave it until 6 hours and see what the 'L' key looks like.

[Merlin]

That's a nice picture there, Tony, that explains a lot in terms of the surface activity.

Just a thought; do the keys sink if you turn them upside down? At the moment, they will fill with gas and float as they are hollow underneath. Maybe we need some sort of grille to hold components down that may float.

Nice work so far.....

[tonyyeb]

Thanks. The keys still float but are most submerged when upside down. But then they wont get any light.

The grill is a nice idea, maybe some kind of mesh. But it would have to be fine for keys. And would it cause tan lines?

[Merlin]

I don't know, mate. One other idea that came to me was to trap them under a sheet of clear plastic, something like Lexan sheet. The sheet won't float but it will still let the UV light through.

[tonyyeb]

Before shot:


3 hour shot:


6 hour shot:


The A has been weighed down for the past 3 hours. It looks a little lighter then the L but not a great deal. Back in they go for another 3 hours, then ill take a final shot.

[tonyyeb]

I think it is safe to say that it has been a success (8 hour shot - had to use the flash but it looks about right irl):



The A key looks a tiny bit lighter than the L. The 1 key is from an A1200 I have waiting to be 'done'. It was in a better condition than the A600 that I did today. The difference is obvious. It would be easier to weigh down all the keys because as the bubbles form, they rise up, get caught by the keys and slowly turn over. I kept having to release the gas from under the keys.