Removing yellowing from plastics - Part 2

[krye]

Sorry about the double post, but it looks like the page 1 thread is dead. I didn't realize until after the fact....


Anyway, moving on....

I'm trying the peroxide/oxy thing with an old Mac LC III. I can't find anything locally that is higher than 12% peroxide. I found a 12% peroxide cream wash at the local beauty supply store. I dumped that in a bucket with my old keyboard and mouse. I sprayed in some liquid "Oxy Clean" that I found at the grocery store. I can't find powder anywhere, so hopefully the liquid spray works.

Anyway, I've had this stuff soaking for a day and I don't see much of a change. Maybe because I'm only using 12% and the Oxy stuff that I bought doesn't have TAED in it.

This stuff is pretty creamy. I hope it works. This is sort of a test run for a Mac Plus that I bought off eBay. I have not received it yet, but I suspect that it is going to have some yellowing on it that didn't show in the pics. I'm trying to nail the process down ahead of time. I think I'll have to pick up a UV bulb today to speed up the process. It's a good thing that we're so close to Halloween. The local party store has Black Lights for $3.

 

[Merlin]

Get a UV bulb; without it, all you are doing is getting the parts wet, the UV light is essential for it to work.

M

 

[krye]

Get a UV bulb; without it, all you are doing is getting the parts wet, the UV light is essential for it to work.

M

I thought baking in the sun all day would have done something. I'm going to pick up a few UV bulbs on the way home tonight.

 

[Lorne]

@ Krye

Sunshine will work fine - it may be that your solution is too weak.

Check out this link: http://www.prochem.com/about/us.php?s=NY
It is a list of distributors of ProChem products in the NY area (proChem manufactures carpet cleaning products).
They will sell you "Urine Rescue" which is approx 30% H2O2 and it costs approx $ 20/gallon.

You should be able to find powdered Oxy in the supermarket - it'll be in a quart sized tub with the powdered laundry detergents.
And pick up a pair of rubber gloves while you're at it.

It looks in your photo, like you are stacking the parts. I found that when I did that, it would only de-yellow the parts getting the sunlight. You might want to use two tubs, or do the parts one at a time (bear in mind that the H2O2 solution will be dead after about three days).

 

[krye]

@ Krye

Sunshine will work fine - it may be that your solution is too weak.

Check out this link: http://www.prochem.com/about/us.php?s=NY
It is a list of distributors of ProChem products in the NY area (proChem manufactures carpet cleaning products).
They will sell you "Urine Rescue" which is approx 30% H2O2 and it costs approx $ 20/gallon.

You should be able to find powdered Oxy in the supermarket - it'll be in a quart sized tub with the powdered laundry detergents.
And pick up a pair of rubber gloves while you're at it.

It looks in your photo, like you are stacking the parts. I found that when I did that, it would only de-yellow the parts getting the sunlight. You might want to use two tubs, or do the parts one at a time (bear in mind that the H2O2 solution will be dead after about three days).

Cool. Thanks for the link.

I picked up some black light bulbs at the Halloween store on the way home from work. I figured they'd be a good source of UV for this project. I tried them and they suck. Can you guys post some pics of the UV lamps/bulbs that you are using?

 

[krye]

Well, it's been 3 days that the LC III keyboard and mouse having been soaking in the 12% H2O2 soup. I didn't think it had done anything since I didn't use the proper Oxy booster and I didn't have a proper UV bulb. To my surprise I actually got some decent results. You really can see a difference!

Before:

After:

Look how clean that mouse is compared to the "before" image! You can totally see how much lighter the keyboard is. Sure, it's still a little yellow, but nowhere near the yellow it used to be. Look at the contrast between the case and the keyboard. It's very noticeable.

Another 3 days in some fresh peroxide and this thing would probably look awesome. I imagine with the proper booster and a UV light and I would have had better results in 8 hours or less. But this definitely proves that with just H2O2, sunlight and nothing else but time, you can get nice results!

 

[krye]

Time to try the case. You can see how yellow it is in the previous shots I posted, but here's a close up.

I picked up some 100 vol peroxide (30%) at the salon supply store. I also found some Oxy powder. I hope this is the right stuff. And some corn starch to thicken it up.

I also picked up some nice UV black lights at the Halloween store for $15 each. I'll let this sit for a few hours and see how it goes. The first attempt at the mix didn't come out as thick as I had hoped, but it is foaming up under the black lights. I'll see how this stuff works and I'll try a thicker batch later.

 

[Lorne]

The Oxy is the same stuff as I used.
And if it's foaming up, it's working.
I found it takes 1/2 an hour or so, for the solution to thicken up.
You should get some good results with this setup.

You might recoat the parts after two or three hours, just to be sure it covered all areas of the parts.

 

[krye]

Nice, no need to try a thicker batch. This stuff is as thick as hair gel now. It's been about three hours and it is so hot that it's warping the bottom of the container. I took off the lights for a half and hour and stuck the bucket in 1" of cold water in the bath just to cool it down. I now have the lights back on.

It's amazing. What was a soapy white liquid is now a hot, clear gel. Very easy to work with. Just don't touch the stuff. I cant imagine what it would do to my skin. I just keep flipping the computer around being sure to dip all the sides in the gel. I'll give it another 3 hours and then I'll rinse it off and check the results. That will put me at about midnight. I'll do another dip tomorrow if it needs it.

Start:

~3 hours in:

 

[Lorne]

What's is creating the heat? The bulbs? I susppect that's the source.
If so, I'd move the bulbs farther away - the process needs the UV from the bulbs, not the heat.
Maybe Merlin could comment on whether or not the corn startch might create heat due to some reaction.

I can tell you exactly what happens when it gets on your hands - it burns, and after ten seconds your skin turns white. Use the gloves and some goggles/glasses. If it does that to your hands, imagine what it would do to your eyes if you got some splashed in them.

 

[Terry Yager]

Use the gloves<snip>

Geeze, even a hairdresser knows that (for sure)...

--T

 

[krye]

What's is creating the heat? The bulbs? I susppect that's the source.
If so, I'd move the bulbs farther away - the process needs the UV from the bulbs, not the heat.
Maybe Merlin could comment on whether or not the corn startch might create heat due to some reaction.

I can tell you exactly what happens when it gets on your hands - it burns, and after ten seconds your skin turns white. Use the gloves and some goggles/glasses. If it does that to your hands, imagine what it would do to your eyes if you got some splashed in them.

Yes, I know. I had goggles and gloves on the whole time. 30% H2O2 is pretty nasty stuff. <sarcasm>Terry, thanks for the great contribution to the thread.</sarcasm>

As far as the heat goes, it's not like the bulbs are warming up the solution. The solution is actually generating its own heat. The bulbs aren't that hot to the touch. There is a reaction happening. I remember this being mentioned previously in the thread somewhere. If not here, then here or here.

It's the next morning and this stuff is now as thick as it can get. I washed it off with the garden hose. It was almost like the frosting you'd get on a donut. Actually, it looks like jizz. Anyway, it's drying outside right now. One thing I did notice is that the solution ate away the paint on the Apple logo. So I am kind of bummed about that. Maybe I can repaint it. I'll post more before/after pictures once I have it dried off.

 

[Lorne]

You need to put something on some of the painted parts or some kinds of decals. I tried candle wax on metal parts and some stickers. It worked sometimes but not other times. I though of axle grease or something thick but that would withstand the heat generated, but haven't tried it yet. A really good painter's masking tape will work with the paste version of the H2O2. You just have to trim around the part you want to protect (and then cross your fingers).

 

[Lorne]

I finally found some time to finish my Televideo 925.

I got it back to the black and white that it used to be.

Here's the before and after photos:

 

[krye]

@Lorne: Looks awesome.

The LC III is done too. Looks like I left it in the sauce for too long. I think I over cooked it. There is no trace of yellow, but the white is a little uneven and even looks a little "frosty" in some places. I knew I should have washed it off at midnight last night, but I got into other stuff and couldn't be bothered. The Apple logo too is toast.

If anything, this serves as a good trial run for the Mac Plus and Mac SE that I'm waiting for. (I bought them off eBay last week. Still waiting for them to be delivered.)

Before:

After:

Before:

After:

Apple collectors be warned. The Apple logo does not survive this process. I'll have to find a way to mask it off in the future. Maybe hot glue?
Before:

After:

 

[Lorne]

Those are some pretty nice results.
What a difference !

I've found that while the paste solution works well for vertical or very large surfaces, the original liquid solution works best for the most even results.
It's either that, or you need to remove and reapply the paste a couple of times during the process to get more even results.

I toasted an Altos label, which are a lot harder to come by than an apple logo.
I wouldn't worry about it - it still looks a whole lot better than it did.

 

[krye]

@lorne: Totally.

Anyway, I figured out a work around for the Apple logo. I hope they are like this on all models. I noticed a hole in the case behind the logo. I stuck a pin in there and pop! The logo came out.

 

[Merlin]

@ Krye

Nice results you got there! Regarding the corn starch, that won't be generating the heat, the heat is due to the TAED in the 'Oxy' catalysing the peroxide.

My recommendation to you if you are getting so much heat is to dilute the peroxide back. Yes, it takes a bit longer, but the heat and possible distortion of parts is much reduced; it's also a lot safer to work with as well.

I'm glad the corn starch worked out as a gelling agent though, it was a bit of an educated guess and isn't that far off the xanthan gum method. I would suggest that you make the gel beforehand with the corn starch (you can store it this way) and only activate it with the 'Oxy' when you need to use it. The gel will be stable on it's own without the 'Oxy'.

 

[Lorne]

And I think Merlin would agree that if you premix it, and store it, you should store it in a container that won't see the light. I'm surprised that your H2O2 came in a clear plastic bottle. Mine came in white plastic bottles, so the UV won't degrade the H2O2. You should probably store it somewhere dark, like in a pantry.

 

[krye]

Thanks for the comments. I think I will definitely tone down the solution next time. It's too white! Almost "ashy". I left it in too long. Next time I'll try maybe 4 hours, wash it off, and then have a look.

Before:

After:

I just have to do the monitor, but I need a break.