New technique for whitening yellowed plastic

[Major Havoc 2049]

 

nice. but you can still see there's a difference

the yellow is now the colour that the rest of the case was and

the rest of the case is now slightly lighter still.

Ya, it isnt perfect, but it still looks way better than before. It helps to keep it out from sun up to sun down, as it hits different angles for a more even look. Considering this technique requires almost no effort, the results are pretty awesome.

[snicklin]

I live in Queensland, with excess sun here, more than I like. I just hope this process won't warp my case.

[Osgeld]

I live in Queensland, with excess sun here, more than I like. I just hope this process won't warp my case.

 

yes 100% yes it is a real concern if you live in an area where the sun gets INTENSE might I suggest putting it in a water bath to prevent that (never had warping issues with liquid retrobrite formula's in the south east USA August sun, where its so narsty your grass turns to dust)

 

I set some 5 mm accrylic out in the sun one day just to see what it would do and it started to make a 90 over the deck rail by the end of the day, you dont want that messing with a thin, old ABS part that's hard to replace

Edited May 30, 2019 by Osgeld

[Sugarland]

An Atari picnic!

 

Exactly. Quite similar to this

 

https://youtu.be/_6ohoHtTNcY?t=7

Edited June 13, 2019 by Sugarland

[Mclaneinc]

I live in Queensland, with excess sun here, more than I like. I just hope this process won't warp my case.

 

You still coming to terms with the sun Steve?

 

But yeah, I'd be worried about warping in that heat too...

[flashjazzcat]

I think there's a greater risk of items being carried away by flood-waters in the UK.

 

Anyway: I tried this briefly on Monday when we had good, strong sunlight, but since experiments were rapidly curtailed by the subsequent deluge of rain, it's still unclear whether anything is actually happening to the plastic.

[displaced]

My XEGS’s plastic bits have been out on a bit of cardboard on the lawn for two days now.  Been a bit overcast here in the UK, but we don’t want blazing heat anyway!

 

Seems to be doing the job!  I’m using the keycaps as a reference since they’ve got a visible line between the yellowed plastic at the top of the key and the unyellowed sides.  That was very visible to begin with, but is very nearly gone.

 

Reckon most of the parts will be done by the end of tomorrow. The spacebar and the grey joystick top on base might need another day or two as they were worse to begin with.  

 

Will post some some before and after pics when it’s all back together.

 

This has worked so well I’m tempted to do the same with my STFM and Falcon. Neither of them were as bad as the XEGS, but they’re not quite what they once were.

[Mr Robot]

You might want to hold off for a little while and see how the XEGS fares over time, if it re-yellows or gets brittle or something. 

 

[adam1977]

I have a white PSOne controller that has yellowed badly over the years, i've been putting it out in the sun on and off for the last couple of months and it's at the point where the yellowing is barely noticeable; i'll post some pics of before and after 

[mimo]

wow, some of my previously retrobrighted stuff is looking a bit yellow again, time to hit the sunbed

 

[KLund1]

Post one, This takes too long!

Wow, I've posted this several times. It works.

1. Beauty supply store, get 'developer 30' cream white.

2. Have a clear plastic container, when upside down, will cover your parts. 

3. wash your case and parts.

4. Paint your parts with developer cream with a 2"-3" paint brush.

5. use a very low nap paint roller to 'smooth' out the cream on all surfaces. THIS IS THE MOST IMPORTANT STEP!!

  I use this:

https://www.amazon.com/Shur-Line-3060C-3-Inch-Touch-Roller/dp/B000FGZMHK/ref=sr_1_8?keywords=paint+roller+kit&qid=1562908925&refinements=p_n_size_four_browse-vebin%3A17870928011|17870929011&rnid=17870926011&s=hi&sr=1-8

6. wet cement with water where the case/part will sit facing the sun.

7. Place case/parts over cement so the water dose not touch parts. cover with plastic clear container.

8. Container should make a good flat/sealed contact with cement. Try not to let moister out.

9. Do this during mid day. At 70' wait 40 minutes. 80' - 30 minutes, 90'-20 minutes. 100' will risk blooming (white discoloring) check progress.

If done, wash, wash, and wash again.

10. if not done, add water to cement. You want a very humid/hot environment for the case/parts. Wait minus 10 minutes from schedule above. Check again. They should be done. If not wash, wash, wash, wash, try again the next day. If you do the same day you risk 'blooming".  Morning, Evening do not work, only midday when the cement is warm/hot.

 

Easy simple, works

 

[adam1977]

That doesn't sound very simple at all, with that method you have to buy products, containers etc. plus it's time consuming...

 

The beauty of this new method is that all you do is put your retro device in the sun and leave it till the yellow is gone, it's simplicity itself 

 

https://www.youtube.com/watch?v=8P1OVj0IcqY

[_The Doctor__]

Don't want to re yellow? use this and the keep the computer cool and in the appropriate light...

[mimo]

I'm impressed. I had a spare 400 cart flap that I left out over the weekend (half of it covered)
It really did work, my camera can't pick up the subtle difference as the flap was not too badly yellowed. 
I have since left it out totaly uncovered and the yellow half is now the same colour as the rest.
I now have a previously retrobrighted and re-yellowed 800XL sitting in the garden, obviously we now have a total blanket of cloud

[_The Doctor__]

gah, folks just don't understand... keep the plastic cool, or the the bromides will migrate.. and again it's suggested to use what I listed... you are shortening the life of the plastic otherwise...

[drpeter]

Scientific literature on the effect of various wavelengths of light on degradation of ABS and similar polymers suggests the following:

 

1) Yellowing is accelerated by UV light, both UVA and UVB across the spectrum

2) Weakening is similarly accelerated by UVA & UVB but as the plastic ages and yellows, visible light also becomes increasingly damaging

3) Bleaching out of yellowing is due to visible light at the blue/violet end of the visible spectrum

4) Yellowing is accelerated by dark because, particularly in normal indoor lighting conditions behind glass, the bleaching effect of visible light exceeds the yellowing effect of UV light

5) Normal glass filters UVB completely but UVA only partially. Laminated glass/windscreen/windshield glass or UV-filtered glass completely filters out UVA also

 

The conclusion to be drawn from this is that in theory the best and safest way to reverse yellowing without damaging the plastic should be by exposure to bright light  in the visible spectrum e.g. bright daylight behind laminated or UV-shielded glass.

 

Note that although the windshield/windscreen of a car is usually UV-shielded, side windows usually are not and the dash of a car in full sunshine might get VERY hot unless it is very well ventilated.

 

Refs.

Searle, N. D., Maecker, N. L. and Crewdson, L. F. (1989), Wavelength sensitivity of acrylonitrile–butadiene–styrene. J. Polym. Sci. A Polym. Chem., 27: 1341-1357. doi:10.1002/pola.1989.080270418

Abstract

The wavelength sensitivity of unpigmented 100 mil thick ABS exposed to sunlight and filtered xenon are radiation was determined by the sharp cut filter technique based on three types of photochemical changes: bleaching, yellowing and loss in impact strength. Bleaching of the yellow‐colored species formed in the processed material is caused by wavelengths between 380 and 525 nm with maximum color change by the 475–485 nm region. Photochemical yellowing is due to wavelengths between 300 and 380 nm with all wavelengths being almost equally effective. The spectral sensitivity based on change in impact strength shifts from the UV to the visible region as photochemical yellowing progresses.

 

Pickett, James. (2004). Reversible post-exposure yellowing of weathered polymers. Polymer Degradation and Stability. 85. 681-687. 10.1016/j.polymdegradstab.2004.03.008.

 

Abstract

The commonly observed effect of weathered polymer samples continuing to change color in the dark was studied in some detail for polycarbonate, styrene–acrylonitrile copolymer (SAN), and various combinations with SAN–polybutadiene rubber graft (SRG) copolymer. All of the formulations became more yellow upon storage in the dark after accelerated weathering, and all behaved very similarly. There was a fairly rapid shift of 1–2b units (as defined in CIELAB color space) over the first two weeks followed by a slower, linear shift that continued for many months. This amount of color shift is enough to be visible to the eye in side-by-side comparisons. Most of the additional color generated in the dark could be bleached by exposing the samples to sunlight through a south-facing window. The samples usually reached the original color after 2–4 days of window exposure. Putting the samples back in the dark caused the yellowing to start up again, although the rapid yellowing often was not as much as the first time. Samples aged under natural conditions outdoors also underwent a small color shift upon storage for 5 months and substantial color shifts after two years.

[Gunstar]

Well, I finally got around to trying to de-yellow my slightly yellowed XL equipment with the straight sun technique. Two days of 10-12 hours a day. The results are quite good. I can still tell by my 1020 printer that the color is not quite back to original judging by the plastic hidden by the 1020's tinted dome, but it's very close! One of my 1050's was quite yellowed, and I was going to paint it instead of attempting the traditional retro-brightening, as masking would have been easier than disassembly due to all the upgrades and port mods I did on it, but now I can happily say I no longer need to paint it! All my XL components now match, close enough, probably needing an electronic eye to tell any difference now. And best of all, my 1200XL which I did paint, after PBI mod body work, with Rust-olium's Antique white, the closest I've found to original XL white, also matches it all much more closely after all the other peripherals got the sun treatment. Don't mind the 1030 and 1010 still looking more yellow than the rest, in real life they match, they just happen to be close to a light with a yellowish glow, and out of the camera flash more, making them look darker in the photo.

 

I also did my Dreamcast and controllers, but they were much worse and need at least another day in the sun.

 

 

Edited September 18, 2019 by Gunstar

[Gunstar]

After another 6-8 hours of 95 degree Oklahoma sunshine (not that the temp means anything) my Dreamcast still looks the same as it did the end of yesterday, marking about 4 total days in full sun shine over the last 2 weeks or so. I don't think I can surpass the whitening process I have achieved, without introducing Peroxide to the equation. It looks really good, much better than it did (I wish I'd thought to take "before" shots on any of these), and especially the controller which was very yellowed; it look fantastic in comparison! But there is still a difference in color between the plastic under the disc door/hood/bonnet or by comparing to the modem on the side which has never yellowed at all. I still have to remove a couple scuff marks on the side. 

 

The Xbox 360 under it is next on the list for sun-whitening, I have to replace the DVD drawer mechanism in it anyway. (I have a half dozen 360's right now I'm using for parts and eventually get 2 or 3 working units out of them) The original Xbox on the bottom is recently repaired and restored.

 

And just for the hell of it, since they were partially in another picture anyway, my two favorite game consoles of all time, the Atari Jaguar w/CD unit and the Panasonic 3DO FZ-1. No retro-brightening required, custom paint on the Jag from a decade or two ago.

Edited September 18, 2019 by Gunstar

[+DrVenkman]

21 minutes ago, Gunstar said:

After another 6-8 hours of 95 degree Oklahoma sunshine (not that the temp means anything) my Dreamcast still looks the same as it did the end of yesterday, marking about 4 total days in full sun shine over the last 2 weeks or so. I don't think I can surpass the whitening process I have achieved, without introducing Peroxide to the equation

I tried sun ("air") brightening a Commodore 64C I have that has a bad "tan" on one side and oddly, along just the very front edge of the curved part of the case. The keys on that side all had horrible tan-lines between the exposed parts of the left side and and where they were shaded by the top. After two full days on two consecutive weekends, I has some decent (not perfect) whitening of the left-side case tan, but zero effect on the yellowed little strip along the front edge. The keys showed no effect at all, sadly.   Fortunately, removing them all, dunking them in a clear container of warm water and liquid 40vol cream peroxide conditioner and covering them with Cling-Wrap film took care of it; it took two days out in the sun - and I left them in the solution covered overnight on the porch in between! - but they came out perfect. 

 

So tl;dr: the type of plastic and degree of yellowing definitely seems to make a difference. I have yet to try my most-yellowed 800 yet, but I will do so perhaps this weekend. 

[tjlazer]

So I have been trying the sun only method and it just doesn't work too well and takes several days or weeks of all day sun to give some improvement.  But never back to original color.  But with the addition of some 40 Volume Creme Conditioner and some hot sun, all it takes is a few hours!  So, which is better for your 30+ year old vintage plastic case?  4 hours with some peroxide brushed on (NOT coverd in plastic wrap, or submerged in a container!), or 1-3 weeks of direct sunlight?

[A8Watcher_808]

I tried the sun method a couple weeks ago for 2 hours on my SNES. It made a pretty noticeable difference. Still far from the original color which you can see from the cartridge cover but much better than the darker brownish/yellow color. I stuck a coin on the bottom right so I could see the color change. It's much easier to spot in person. Haven't tried this with my 130xe yet but that isn't nearly as bad.

 

[_The Doctor__]

I can't stress how much a serious scrubbing is needed before either process is attempted...

[siccoyote]

I like this method because it requires that I do barely anything and have to buy nothing.

 

I'm in the UK, Heat and Sun are in short supply. But I am willing to leave a tub of keys outside for weeks and just see what happens. Even if it's not back to mint condition it's better than nothing, and worth the amount of effort put into it.

 

 

That's the Before, lets see in a couple of weeks. I've kept the space bar on the keyboard as a control.

[displaced]

1 hour ago, siccoyote said:

I like this method because it requires that I do barely anything and have to buy nothing.

 

I'm in the UK, Heat and Sun are in short supply. But I am willing to leave a tub of keys outside for weeks and just see what happens. Even if it's not back to mint condition it's better than nothing, and worth the amount of effort put into it.

 

 

That's the Before, lets see in a couple of weeks. I've kept the space bar on the keyboard as a control.

I did the same with my XEGS in the UK last year. Took a good couple of weeks but there was a noticeable improvement!

[siccoyote]

Well I've had the keys outside for 2 1/2 partially-sunny-mostly-cloudy days

 

I guess i's oo early to expect any type of results. But I was surprised.