Removing Yellowing from Plastics - Part 3

[tezza]

Actually it doesn't look too bad being a pale lemon colour. Adds a bit of contrast

But I go with what Lorne suggests. If you can find a piece of the part that's never been exposed to the sun, that should show you what you're aiming for. With enough time it should get there.

Tez

 

[snq]

Let me post some pics of my first retr0bright experience

So I had an Amiga 600 keyboard that looked like this


In case it's hard to tell how bad it was, here's another "before" pic.


So after a day in the sun, here's the result!
Some of the white keys are still slightly yellow, I'll put them back in the bath for another round tomorrow. Other than that, I'm very impressed by the result!


Some more comparisons.. Before the treatment, the keys on this A500 looked bright white in comparison, so I put those in the 600 meanwhile.


And look now! And the "P" is one of the treated keys that is still slightly yellow.


My mixture was: 600 ml hydrogen peroxide 3% strenght (weak but that's all I could get at the pharmacy), a teaspoon of glycerol as it's labeled here, and finally about 1/3rd of a teaspoon of Vanish Oxy. I put it in a jar, put in the oxy, mixed, put in the key caps, and then put it outside in the sun. I also stirred it a couple of times during the day.

I'll post pics of the final result once I'm completely satisfied with it

 

[Lorne]

My mixture was: 600 ml hydrogen peroxide 3% strenght (weak but that's all I could get at the pharmacy), a teaspoon of glycerol as it's labeled here, and finally about 1/3rd of a teaspoon of Vanish Oxy. I put it in a jar, put in the oxy, mixed, put in the key caps, and then put it outside in the sun. I also stirred it a couple of times during the day.

Nice results. I hope you wash your hands before you start typing now - you don't want those keys getting dirty !

FYI: you don't need the glycerol if you're making a pure liquid solution. The glycerol is used to help the Xanthan Gum mix better with the H2O2, for the paste version.

 

[snq]

Nice results. I hope you wash your hands before you start typing now - you don't want those keys getting dirty !

FYI: you don't need the glycerol if you're making a pure liquid solution. The glycerol is used to help the Xanthan Gum mix better with the H2O2, for the paste version.

I always wash my hands before touching any of my old stuff

That's good to know I don't need the glycerol. Altho it's not like this bottle is going to be empty any time soon, the smallest container they had was 300 ml

I bought some thickener as well, tested a bit with pure water to get an idea of how much is needed, it seems to be about the same as the xanthan gum. I just need to get some more H2O2 and then I'll start experimenting with that as well and I'll post the results afterwards.

 

[Merlin]

Thanks for that snq, it's all good stuff!!

 

[snq]

A bunch of keys are still very very slightly yellow, but I think it's only visible if you're really looking for it. I might do them again sometime once I get a hold of some stronger H2O2.

So here's another before pic, the only pic I have with the keyboard actually in the case.


And now.. Ta-da

 

[tezza]

Nice.

I found a had a few "stubborn" keys on my Apple IIe which didn't de-yellow entirely. I gave them some extra time in the H2O2 and found the yellow disappeared but they became streaky and the lables faded a little. You probably did the right thing stopping where you did. It looks just fine.

Tez

 

[snq]

Today I tested the paste version, with great results I must say!

My recipe for today:
250 ml H2O2 17.5%
1 teaspoon of glycerol
2 food spoons of food thickener
1/3rd teaspoon of Vanish Oxy
And about 3 hours of full exposure to the sun.

Just for the heck of it, I tested with one of these panels. They are from a late 90s tower case and already this yellow even though they've been in a closed cardboard box the past 5 years.
I think it's pretty easy to tell which one of them got the treatment...


Then I had an external Amiga diskdrive which was amongst the yellowest objects I have.. I'm not sure what happened, I put some tape on it right in the middle and only put the paste on half of it to be able to see the difference. But the other half came out pretty much just as bright.. The only place where it was still yellow was where the tape has been. It's pretty windy today so my best guess is that the foam must've blown over to the other half which caused a reaction there as well.
Luckily I only did the top half of the casing, so I can still show the difference.


The largest object for today was the top of a cartridge holder. Here's the best before picture I could find..


And it came out like this! The brighter spots on top are because the plastic is thinner there. There are no miscolorations whatsoever.


I'm extremely satisfied with this result Especially because it only took a little under 3 hours. I had to add more paste every hour and there was no foam, probably because of the wind.

Out of curiosity, I'm wondering how others work with the paste? I made 250 ml at once, and used maybe about 100 ml the first round, and I had enough left to reapply another 2 times. But I'm wondering if you make everything at once or if you create a new mixture just before reapplying?
I mixed my stuff in a catfood tin and placed a dark dish on it to keep the sunlight out. It did foam a bit while in storage for an hour, but not too much.

 

[tezza]

Good result!

I use my original paste for all reapplications. I just keep it in a dark place until I need it again. In the past it's been almost all used up by the time I get around to the final re-application, which has sometimes been as long as day 3.

Tez

 

[snq]

I use my original paste for all reapplications. I just keep it in a dark place until I need it again. In the past it's been almost all used up by the time I get around to the final re-application, which has sometimes been as long as day 3.

Do you get any foaming if it's stored in a dark place? I'm wondering why I got some foam even if I don't see any way for light to get into the tin. Perhaps I used a bit too much Oxy?

I know this has been said before but I think it doesn't hurt to mention it again.. This H2O2 is very aggressive stuff at 17.5%. I apparently got some on my thumb while taking off my protective gloves. A couple of minutes later it started to sting repeatedly, it felt a bit like insect bites. I also got a white spot on my thumb that wouldn't wash off. About an hour later it was completely gone, both the stings and the white color. But make sure to wash your hands (and anything else that may have come in contact) properly after using this stuff, even if you've used gloves!

 

[tezza]

Do you get any foaming if it's stored in a dark place? I'm wondering why I got some foam even if I don't see any way for light to get into the tin. Perhaps I used a bit too much Oxy?

The foaming is not caused by light. It's as a result of the chemical reaction between the Oxy and the H2O2.

I'd say you got a lot of foaming because your H2O2 is fairly strong. A hot mixture can also increase the foaming. Did you heat yours as I did with my arrowroot food thickener?

I got some foaming with my efforts but it was mild. But my H2O2 was only 6% so I think that's the difference.

Tez

 

[snq]

The foaming is not caused by light. It's as a result of the chemical reaction between the Oxy and the H2O2.

I'd say you got a lot of foaming because your H2O2 is fairly strong. A hot mixture can also increase the foaming. Did you heat yours as I did with my arrowroot food thickener?

I got some foaming with my efforts but it was mild. But my H2O2 was only 6% so I think that's the difference.

Tez

Aha, okay.
No, I did not heat it at all. So I guess it's the strength then.

About the strength, if I want to make it weaker (and have more..) can I use regular tap water or does it need to be distilled?

 

[Lorne]

Do you get any foaming if it's stored in a dark place? I'm wondering why I got some foam even if I don't see any way for light to get into the tin. Perhaps I used a bit too much Oxy?

I also got a white spot on my thumb that wouldn't wash off. About an hour later it was completely gone, both the stings and the white color.

I've always used my batch of paste the same day, and if I needed more, I just mixed some more the next day.
I'm surprised that you are mixing it in a cat food tin. I've always used plastic or glass containers, as I've found that the H2O2 solution/paste reacts with metals.

Having accidently splashed myself, touched a part without gloves on, etc, etc, numerous times, I can tell you that the white spot on your thumb was a layer of skin that you killed, and it just washed off afterward. Repeat that in the same spot several times, in quick sucession, and you'll get to see your flesh, that was under all that skin.
Wash your gloves off with the garden hose or in the sink, before trying to take them off !

 

[snq]

I've always used my batch of paste the same day, and if I needed more, I just mixed some more the next day.
I'm surprised that you are mixing it in a cat food tin. I've always used plastic or glass containers, as I've found that the H2O2 solution/paste reacts with metals.

I didn't see any reaction, the tin looks just like it did before and I didn't see any weird stuff in the paste either. But I emptied the tin within 2 hours and washed it afterwards, I wasn't planning on letting it sit for several days.
But I'll keep that in mind next time.

Having accidently splashed myself, touched a part without gloves on, etc, etc, numerous times, I can tell you that the white spot on your thumb was a layer of skin that you killed, and it just washed off afterward. Repeat that in the same spot several times, in quick sucession, and you'll get to see your flesh, that was under all that skin.
Wash your gloves off with the garden hose or in the sink, before trying to take them off !

I'm not planning on repeating that, but I guess it was a good way to show that this stuff can actually be dangerous. Hope this prevents someone else from making the same mistake, it wasn't the most pleasant experience even though there wasn't too much damage done.

 

[tezza]

I'm surprised that you are mixing it in a cat food tin. I've always used plastic or glass containers, as I've found that the H2O2 solution/paste reacts with metals.

Yes, I've always kept mine in a (non-reactive) plastic container between applications.

I would imagine normal tap water would be ok for dilution. It may have traces of chlorine/flourine and aluminium salts in it (most tap water does). I'm no chemist but I can't see these trace amounts as having any detrimental effect?

Tez

 

[Yzzerdd]

I don't think this has been mentioned yet....

I was talking with my chemistry teacher, and he was pretty interested in what we are doing. I'm going to show him the site tomorrow. We did a lab using really strong hydrogen peroxide (40%, I think), and he said that the stuff will naturally start breaking down into a weaker solution. He said the best way to stop this is to keep the hydrogen peroxide in a dark place and cold, so the refrigerator would be ideal to keep the maximum concentration longer. Just thought those buying this stuff in bulk would want to know, or storing it for a while.

--Ryan

 

[Lorne]

He said the best way to stop this is to keep the hydrogen peroxide in a dark place and cold, so the refrigerator would be ideal to keep the maximum concentration longer.

--Ryan

Correct, I've found that the H2O2 degrades to nothing after about three days in the UV.
The stuff I buy comes in a white plastic container to keep the light out.
If you store it, don't store it in a clear plastic or glass container, and if you have young kids at home (or who visit), I wouldn't be putting it in the fridge either.

 

[TrekkiesUnite118]

I am thinking of trying this on my old Gameboy. Has anyone done this yet on a Gameboy and have any tips? I was thinking that since it's small it might be easier to do the liquid version instead of the gel as from what I understand there would be less chances of it getting damaged from not reapplying soon enough.

 

[Merlin]

You should be Ok with the liquid version. Keep the strength of the H2O2 below 10% and you should be fine.

 

[Lorne]

I am thinking of trying this on my old Gameboy. Has anyone done this yet on a Gameboy and have any tips? I was thinking that since it's small it might be easier to do the liquid version instead of the gel as from what I understand there would be less chances of it getting damaged from not reapplying soon enough.

My son was wanting me to do his gameboy as well, but I haven't got around to it yet. Take before and after photos - I want to see how this one turns out.

And I'd definately use the striaght liquid H2O2 & Oxy solution for something that small. Just make sure you stir it up about once an hour, as the bubbles collecting on the underside, tend to make the pieces float up out of the liquid.