Removing Yellowing from Plastics - Part 3

[Lorne]

@gerryDoire:
As an ex-canuck I know how it was - lots of regulations.
I got my 30% H2O2 concentration from a company manufacturing carpet cleaning solutions. It was called "Urine Rescue" and was manufactured by ProChem - you might check to see if if they have branches in Canada, or maybe one close to the border (wink, wink).

@Tezza:
Well done man. I've been busy with other stuff, but I'm watching to see what the results are like. It'd be good to get the right formula sorted out. Get some glycerine - I think that makes the drying out process even slower. I can't believe you have to pay that much for a blacklight. The one I got (and sliced my hand opening it) was $ 19 at Home Depot (you don't have those there yet I suspect). I've now hooked up four of them providing some good UV in the garage (no more flies here!).
And I know you're just doing this to get on CNN before Merlin does.

@ALL
VERY IMPORTANT: When mixing this stuff with a hand mixer or whatever, PLEASE make sure your are using eye protection and gloves ! I got lazy, and lucky the other day, and had some splash 1/2" away from my eyeball. Now the safety glasses sit right next to the H2O2 bottle, and I don't touch it without putting the glasses on first.

@JDW:
Thank you - good to know, as I had no idea what the color was supposed to be. I have a couple others to do, and I'll monitor the de-yellowing process more carefully on those.



I guess this means my previous comment that you can't de-yellow something too much, is incorrect, and especially with Apple plastics. I've noticed some blotchiness with Apple plastic de-yellowing as well, that I haven't seen anywhere near as bad on other manufacturers stuff. It's definately something to watch out for.

.

[tezza]

VERY IMPORTANT: When mixing this stuff with a hand mixer or whatever, PLEASE make sure your are using eye protection and gloves ! I got lazy, and lucky the other day, and had some splash 1/2" away from my eyeball. Now the safety glasses sit right next to the H2O2 bottle, and I don't touch it without putting the glasses on first.

Agreed. I wore safety goggles even with my 6% H2O2. Nothing spashed about but it's worth the insurance.

In fact, I didn't want to admit I used a hand blender at all as I consider it less that ideal safety-wise, but it was all I had.

I've now ordered a florescent push-and-screw type light off our local auction site for $35 ($18 US). Much more reasonable. I should be up and running again by the weekend.

However here are some "prelimary" results. The case is only partly de-yellowed so far. The centre strip was covered with tape. The left side had the Xanthan Gum/glycerine mixture, the right side had the Arrowroot.

Both pastes had the same number of applications. I applied it four times on the Saturday as the cases dried out. It was very gloomy and sometimes we even got light rain. I had hoped the sun would come out (it didn't!). At the end of the day I could see only a very slight visible de-yellowing, and that was only when I pulled the tape back to reveal the original colour. Not enough UV that day.

On the Sunday the case got only ONE application of both pastes at the beginning of the day. As explained in an earlier post, I'd run out of mixture as I'd also re-treated my RX-8000. Sunday was a partly cloudy day with about 50% sun and lots of wind. Very good drying conditions. I just let the case dry out and sit outside all day. The Arrowroot formed it's characteristic "scale", the Xanthan gum/glycerine did not.

Even with that one pasting, which dried soon after it was applied, the de-yellowing was noticable once the day was up (even though the process was nowhere near complete). I checked on the cases from time to time and despite both areas being quite dry, a slow and patchy deyellowing seemed to be occuring over the length of the day.

Here is the result.

More treatment is required but you can see both the Xanthan gum and Arrowroot have had an effect. Both are patchy to a degree but the Arrowroot is maybe more patchy than the Xanthan gum. This is what I'd expected.

I'll finish the treatment with a UV light this weekend. I'm confident both pastes will eventually turn the machine back to it's natural grey. My tentative conclusion at this stage though is that the Xanthan gum/glycerine is the superior treatment due to its transparency and the fact it doesn't dry out as fast. My observations agree with yours Lorne.

If that proves to be the case at the end, I'll be recommending that people use Xanthan Gum/Glycerine. Unless they can't get hold of it in which case the more readily available Arrowroot is a useful alternative, but it will need reapplying more often.

There is one concern. I'm wondering with BOTH treatments, if the lighter pieces on the textured part of the case (around the keyboard) are not the natural grey of the case at all but rather a "white bloom" due to very high concentrations of peroxide formed under the dried mixture and attacking the plastic. Similar to what happened with the Atari on the Retr0Brite wiki in the "Perils and Pitfalls" section.

I guess I'll know when the process is complete.

Tez

[AndyR71]

@gerryDoire: @ALL VERY IMPORTANT: When mixing this stuff with a hand mixer or whatever, PLEASE make sure your are using eye protection and gloves ! I got lazy, and lucky the other day, and had some splash 1/2" away from my eyeball. Now the safety glasses sit right next to the H2O2 bottle, and I don't touch it without putting the glasses on first.

To be clear, because I'm the one who mentioned this tool: I'm using 35% peroxide and adding it at the end, by hand, with a plain old wire whisk. The mixer is used only to blend the xanthan gum into the oxy/water mixture. That's kind of the point: isolating the dangerous component expands the space of tools that can be used safely.

[Merlin]

That's why I said to use a hand blender or a liquidiser in the Wiki; hand blenders tend to be taller than hand whisks and liquidisers can be sealed via the lid.

As long as you protect your eyes and hands, there's no reason why you couldn't use a wire whisk; some of the guys on the French forums (such as Fneck) are doing exactly the same thing.

[patscc]

This might have been mentioned earlier, but have you guys tried keeping the temperature of the solution warm, and providing for either agitation of the unit, or agitation of the solution, over time ? Kinda like etching PCB boards with a solution of ferric.
patscc

[Merlin]

@patscc

Absolutely not. Heat doesn't help here and may encourage distortion of the plastic, particularly on large or thin parts.

Agitation is irrelevant, since we are triggering a reaction on the surface of the plastic; simple Brownian motion of the peroxide molecules in the solution is enough. If you are using the gel, agitation is totally irrelevant since it's not mobile.

@ JDW

Baking soda is only added to toothpaste as a mild abrasive that doesn't damage tooth enamel. We don't want to be abrading the surface with anything like this as it's a chemical effect we are generating.

I'm not sure of the food and drug status of TAED, therefore I am unable to comment on it's possible use as a peroxide catalyst in toothpastes. I will have a dig around though and see what I can find out. The only major reference is the US FDA CFR 21 registers.

[lumpydog]

I'm trying the de-yellowing on my first Mac 512K parts.
I'm not sure how they're supposed to look, as I've never had a Mac 512K before.

Look at this before photo of the keyboard.
Is the spacebar supposed to be a different color from the rest of the keys? (Krye's spacebar on page 8 of Part 2 seemed to be a different color as well)

Attachment 1486

In this photo, I've de-yellowed the keys, but the spacebar came out much lighter than the rest of the keys.

Attachment 1487

Now here's the inside of the spacebar - it's much darker than the outside after de-yellowing.

Attachment 1488

And is this the color the keys are supposed to be?
They've changed color after being processed, but I don't know if they've been de-yellowed enough, too much, or just right.
I haven't seen these sorts of colors on anything else.
Are Apple products that different?

All:

I posted in the Part 2 thread, but thought I would follow up on this post since I have been focusing on de-yellowing Apple Compact Mac plastics - specifically, a 512K and a 512Ke (and peripherals). I have been using a very diluted percentage of Hydrogen Peroxide (3% to 1% H202) and seen excellent results. The Apple Compact Mac plastics do not seem to need such high percentages of H202.

Here are the items I have been using: http://www.flickr.com/photos/34964865@N07/3244962958/

For my Apple plastics, I have found that the store bought bottles of hydrogen peroxide (which contain 3% Hydrogen Peroxide) can be mixed with water to fully submerged the plastic. I've mixed the store bought Hydrogen Peroxide with up to 2/3 water to bring the H202 percentage down to as low as 1%.

I use a heaping tablespoon (give or take) of Oxi Clean for each gallon of water/H202 solution.

In general, with the exception of my spacebar, it takes about 6 hours in sunlight to fully remove any yellowing from Apple Compact Mac plastics. I have been cleaning my Apple plastics in batches (each item in a clear plastic container of solution in the sun for 6 hours). I have been throwing the space bar in each batch. The spacebar took about 5 six-hour cleanings to get to the same color as the rest of the keys.

After cleaning, I have been wiping down the plastic with 303 Aerospace Protectant.

Here are some results:

My mouse
Before: http://www.flickr.com/photos/34964865@N07/3244960518/

After: http://www.flickr.com/photos/34964865@N07/3244960944/

My HD20 Case:
Case before (you can see the footprint where the Mac used to sit on top): http://www.flickr.com/photos/34964865@N07/3245545696/

Case in the solution (used clear plastic to allow max UV penetration): http://www.flickr.com/photos/34964865@N07/3244719829/

Case outside in the sun (UV): http://www.flickr.com/photos/34964865@N07/3245545344/

Case after: http://www.flickr.com/photos/34964865@N07/3245552112/

My de-yellowed 512Ke and peripherals:

Photo series: http://www.flickr.com/photos/33624199@N08/3302578478/

Note the photo navigation to the right - this series of photos shows the 512Ke Case/keyboard/mouse, all after H202 cleaning and 303 Protectant. Also in this series are some keyboard closeups showing an H202 treated keyboard and before/after shots of 303 protectant - to try to show the effect of the 303 treatment.

Overall Observations

1) I have experienced no "collateral damage" thus far. That is to say, no logos, screened on labels, serial number labels or model number labels have been harmed or faded. AS you can see in the pictures, I did remove the square Apple logo from my HD20 case by popping it out of the case (push from the hole behind it). The paper serial number label on the bottom of my mouse, HD20 and Mac 512 cases look fine (there was some absorption around the edges of the serial number labels, but it dries out). On my Mac 512K cases I left the square Apple logos on and experienced no damage.

2) The insides of the HD20 case and Mac 512 cases were not effected in any way that I can see (Some have asked if the aluminum-based coating oxidized in any way).

3) Outside temperature does not seem to effect things. I've done this in low 30 degree temps and high 50 degree temps - same results. The sun has been low in the sky (it's winter here in Massachusetts).

4) The percentage of H202 can be very low and still work. When I washed my Mac 512 cases, I could not find enough bottles of H202 to get the plastic bin more than 1/3 full. I used water to fill the bin to the point where the case was fully submerged.

5) The Oxi powder may not fully dissolve at first. It's ok, just leave it in the bottom of the container/solution.

6) After the plastics come out of the solution and are dry, I've been using "Aerospace 303 Protectant" on them. The 303 Aerospace Protectant has a UV block. Additionally, to me the plastics seem dry and very subtly uneven in tone. Adding this solution seems to enrich the plastic, even out the tone and has the nice byproduct of providing some ptotection. Unlike Armorall (which can be oily and wet/shiny looking), the 303 Protectant leaves a non-slick and "more natural" finish.

7) Be careful with steel screws - they do oxidize.

Let me know if you have additional questions.

Lumpy

[Terry Yager]

That's why I said to use a hand blender or a liquidiser in the Wiki; hand blenders tend to be taller than hand whisks and liquidisers can be sealed via the lid.

As long as you protect your eyes and hands, there's no reason why you couldn't use a wire whisk; some of the guys on the French forums (such as Fneck) are doing exactly the same thing.

I get the impression we're bumping up against some language/translation issues here. Would someone please clarify the terms "hand blender," "hand mixer," and "liquefier(?)"? Pictures would help.

--T

[tezza]

All:

I posted in the Part 2 thread, but thought I would follow up on this post since I have been focusing on de-yellowing Apple plastics - specifically, a 512K and a 512Ke (and peripherals). Unlike many in this thread, I have been using a much more diluted percentage of Hydrogen Peroxide (3% to 1% H202) and seen excellent results.

Well done lumpy. Certainly my 6% works well enough given enough UV. Good to know the indications are you can go even lower. Did the increased oxy concentration help with very low concentrations of H2O2 I wonder?

Did you find the immersion technique expensive? Over the counter stuff has a significant markup?

Tez

[AndyR71]

I get the impression we're bumping up against some language/translation issues here. Would someone please clarify the terms "hand blender," "hand mixer," and "liquefier(?)"? Pictures would help.

This is what I'm using:

http://www.amazon.com/Cuisinart-CSB-.../dp/B000EGC9SG

It's also fantastic for any kind of sauce or soup. You can puree tomatoes right there in the pot, and will probably never buy canned pasta sauce again.