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How to remove yellowing from an old Atari case


mimo

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I use pure creme peroxide, since I found Oxy makes the process too "brutal" and risks blooming. In any case, these XL cases and XE keyboards can easily be processed in a day providing there's decent sun, so I find no use for accelerants of any kind.

 

As for frequency of re-yellowing: it seems to depend on the plastic (some XLs re-yellow faster than others), although I'd be inclined to suggest that peroxide treatment would tend to speed up subseqent yellowing if the plastic is not anti-UV treated. The XLs I'm restoring at the moment were all good as new after being cleaned up in 2010, and far from being left out in the sun on a table top, they had been stored in the shade on shelving. However, they steadily re-yellowed. The same thing happened with various XE keyboards I treated around the same time: some were kept in bubble-wrap in a box, and still emerged yellow.

 

However, I'm getting good results with the PrintGuard spray. An XE I restored almost a year ago (case and keyboard were extensively discoloured) and treated with PrintGuard before depatch to the new owner is still (judging from recent photographs) in the same cosmetic condition it was in when I sold it. So - I think anti-UV treatment might be prudent.

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Just found a nice "rain or shine" method. I have a 500W halogen work light from Home Depot. I think it was $20 or so. I took the UV glass out of the front of it and set it in the bathtub (metal tub, btw.. this might not be a good idea for composites- also, don't look at the bulb directly without the glass). I brushed on some Peroxide 30/Xanthan Gum mix and let it blast away, checking in for a turn and a rebrush every so often. It took about 2 hours to restore a fairly browned 800XL top.

post-3606-0-02733700-1329269912_thumb.jpg

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Hmmm! This is starting to look like something I could actually do. Not in my (plastic) bathtub, but definitely in the basement. Get a halogen lamp, some peroxide cream, and some UV protectant spray and I could finally get some of my cases looking new!

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Nope - I should have made it clear that I'm using Lyson Print Guard. That's a UK link, but you should be able to find it elsewhere. I can't speak for the results of any other brands. Maybe the one you've linked to is effectively the same.

Edited by flashjazzcat
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Hmm. Thanks for the clarification. If I Google "Lyson Print Guard," that's what comes up (the one I linked to originally), among others. It appears to be from the same company. The symbol is the same anyway. It's just smaller on the UK version. Or so it appears to me. But nowhere on the front of those cans does it say, "Lyson." Here's a place that claims that stuff is Lyson Print Guard. Maybe different packaging in the US?

 

I may have to buy one and find out.

 

Anyway, thanks again for the clarification that the brand is Lyson. :)

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If memory serves, the first time I started looking for Lyson PrintGuard, a tin with that design on the label came up, but it was from a US vendor. Perhaps Lyson's UK product line does indeed have different packaging, so you might be in luck with that one. It's not exactly cheap over here (£10-15 a tin), but it does last quite a while.

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Wow, that looks really great now!

 

One thing I have trouble understanding is how to get it all to come out evenly. Does everyone use five or six light sources at once, so that every side is bathed in light? Or do you do one side at a time? And what about the crevices? It seems that if light is a critical component of the process, it would be very difficult to get it to come out even, unless you do it a single surface at a time. But that seems far too time-consuming, particularly with items that are shaped like that monitor, with its control panel area.

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Wow, that looks really great now!

 

This is it reassembled and working with a VBXE 1200XL:

 

post-21964-0-28239700-1330277363_thumb.jpg

 

The RGB wasn't working when I dismantled it and I was all ready with the soldering iron... but it somehow righted itself. Tube is super-sharp on this one, and colours extremely vibrant. It also gives the best Y/C picture of any CRT I own. All it required was a slight pincushion adjustment using a pot on the board.

 

One thing I have trouble understanding is how to get it all to come out evenly. Does everyone use five or six light sources at once, so that every side is bathed in light? Or do you do one side at a time? And what about the crevices? It seems that if light is a critical component of the process, it would be very difficult to get it to come out even, unless you do it a single surface at a time. But that seems far too time-consuming, particularly with items that are shaped like that monitor, with its control panel area.

 

It's not easy to get an even result, but this is usually because the discolouration tends not to occur evenly in the first place. If you look at this monitor in certain lights, you'll see that there's a trace of streaking on the front (where it was most severely discoloured), but I decided to call it a day when the chance of blooming, etc, outweighed the likelihood of further improvements. Indeed the objective, in a case like this, is not necessarily to achieve the original colour, but to achieve an even colour.

 

Regarding light sources, naturally with a monitor, the bezel is easiest to position on a windowsill for exposure to the sun. In this case, the bezel also needed the most work. The back cover was in better shape, so I was content to coat it with perioxide and leave it on the bench not far from the window, where it could catch ambient light. It was thereafter a case of washing and recoating, gradually confining activity to the most stubborn areas, and repositioning parts near to the light source as appropriate. I'm becoming more partial to ambient light when Retr0Briting. I think the reaction is most balanced when the light source isn't too searingly intense. A slow reaction tends to produce better results than a fast one, especially when discolouration was severe. I'm never putting OXY into the mixture again (since the last job I tried it with bloomed badly).

 

This monitor was done with pure 40 vol creme peroxide, and took a total of around eight hours in weak daylight.

Edited by flashjazzcat
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It sounds as though there is something of an art to Retr0Briting. One of these days I'll give it a try. The latest 1200XL I purchased has a pretty good case, but it is yellowed enough that you can tell. Not terrible, but not very nice either. I disassembled it and then cleaned it up with soap and water. That got rid of the grime, but the yellow's still there. So it looks like I'll have to give the Retr0Briting a try. But, first, I have to get the modding done. :)

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Somebody needs to test the effectiveness of the spray by treating a some white XL-equipment (say a 1030 you don't care about anymore), spraying it with the protective coating, and then deliberately hanging it out in the sun. I expect nothing would last that, but if you covered 1/3 to protect, sprayed 1/3 to test coating, and left 1/3 totally unprotected, it would make a nice experiment.

 

Maybe a 1027 case would be good for this, no?

 

This is a great thread! Thanks to all for this info.

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