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How to remove yellowing from an old Atari case


mimo

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Ok, I know this is 8 bit retrobriting, but I also own a bunch of ST stuff.. and thats what I am looking to retrobrite right now.

 

It is Grey, so.. will it bring it back to grey? or white?

 

James

Be careful with them! The 65/130XE as well as the ST cases are very susceptible to "bloom".

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Not sure it will help, but check out this blog:
https://www.retrohax.net/atari-130-xe-restoration-and-upgrade-job/
https://www.retrohax.net/atari-800-xl-u1m-and-restoration-2/
https://www.retrohax.net/various-hax-part-one/

This guy retrobrites without exposing plastics to sunlight, uses warmth instead. Just covers plastics with 12% peroxide cream, wraps carefully in black foil, then keeps it in dark warm place for one week. This treatment seems to be quite "safe", I mean, looks like prolonged procedure and avoiding UV-light prevent plastics from partial discoloring etc. imperfections.

I think the best way is to retrobrite something cheap and easy to replace first. Such as an old XC12 recorder, or STM-1 mouse. When you fine with the outcome, use the same treatment to your precious ST case.

Edited by martinez
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just like bbq slow and low, with even treatment of sauce = mmm mmm good

 

besides blotching which is mostly due to uneven paste application, my biggest beef if BLEACH WHITE, like that darn 8 bit idiot, everything he does turns titanium white and blotchy, ya that keyboard was platinum silvery grey, not RGB 255,255,255, and that osbourne was medium grey, not winter alps snow

Edited by Osgeld
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  • 2 months later...

I like to do my ST cases, in fact I do all my cases, in the summer time. The sun warms the backyard patio cement.

I use a paint brush to put the beauty supply store 30 Developer on a case. Then use a low nap 3" cheap paint roller to evenly coat the case. This really stops the Blooming. I then spray the cement with water, place the case over it, then place a clear plastic Rubber Maid type box over the case. This keeps things moist and warm. On really warm days, I'll put a coffee mug of warm water in there to keep the moisture up. I check the process after about 20 minuets. By then cream has turned clear. Most cases are done by now, but not all. If not, I'll respray the cement and let it sit for another 20 minuets. By now almost all cases are done. Wash them up, and let dry a day, then spray with a clear lacquer of your choice so it stays looking new. But for those stubborn cases, I will Not put it out again. I'll go wash it off, and let it cool down to room temp for a couple hours, or maybe the next. Then repeat above. I'm in the mid latitudes of the USA, and these times work for me. But you might have to adjust your UV exposure times on where you are in the world.

The paint roller, moisture, summer heat, and UV, seem to be the best combination, imp.

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just like bbq slow and low, with even treatment of sauce = mmm mmm good

 

besides blotching which is mostly due to uneven paste application, my biggest beef if BLEACH WHITE, like that darn 8 bit idiot, everything he does turns titanium white and blotchy, ya that keyboard was platinum silvery grey, not RGB 255,255,255, and that osbourne was medium grey, not winter alps snow

 

I've been reading about Retrobright since it's start in 2008 but only now started to get some experience with it, thnaks to Fred_M.

 

As far as I understand, you actually cannot "overdo" retrobrighting. It is NOT something like bleach. If the process was like bleaching, every part of the plastic would become lighter equally. So, parts that were more yellow would relatively still be more yellow than oher parts, but that is not how retrobright works, it only "attacks" the yellow.....

 

Proof for this are f.i, keycaps which are usually more yellowed on top. Even though completely covered in peroxideand fully exposed to UV light, the outcome of the plastic is very even.

 

I've watched a number of 8 bit guy's videos and most of his results are simply good and look like returned to original color.

The Osborne actually was as light as it turned out, maybe his camera is not the best in color or his lighting is a bit too much, but I've searched the web for printed matter (flyers etc.) and the Osborne was near white....although of course pictures/scans of (old) printed matter is of course also subject of different color appearance....

 

Except for they keys and the leather handle (the last was a very stupid mistake, I noticed he had packed it in the plastic wrap too and immediately felt that that was wrong....) the Osborne wasn't ruined. The streaking can easily be fixed by doing another (good) session.

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I've watched a number of 8 bit guy's videos and most of his results are simply good and look like returned to original color.

The Osborne actually was as light as it turned out, maybe his camera is not the best in color or his lighting is a bit too much, but I've searched the web for printed matter (flyers etc.) and the Osborne was near white....although of course pictures/scans of (old) printed matter is of course also subject of different color appearance....

 

Except for they keys and the leather handle (the last was a very stupid mistake, I noticed he had packed it in the plastic wrap too and immediately felt that that was wrong....) the Osborne wasn't ruined. The streaking can easily be fixed by doing another (good) session.

You can totally overdo it. Dried out peroxide in high concentrations creates "blooming" (the white patches) and the only way to get rid of that is to remove top layer of plastic or paint it. The 8-bit Guy has demonstrated some good Retr0Briting results, but he pretty much ruined that Osborne. Sure: he may have overdone the keyboard and the case went a bit wrong and the leather strap, etc... maybe he'd do things differently next time, but these are bloody expensive mistakes and not fixable by slapping on more peroxide. Best way to avoid this is to keep a close eye on progress and clean off and re-apply peroxide at regular intervals. It's a pain, but saves a lot of problems later on.

Edited by flashjazzcat
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Do you have any cases that it went irreversibly wrong ?

 

I know my buddy Fred_M screwed up keys of a 800XL....it's probably one kind of keyboard that has those "wrong" caps as he told me he hadn't have any problems with others. Personally I would only treat the beige parts of XLs, they're easy enough to separate from the brown stuff....

 

I haven't done any retrobrighting myself so I don't want to sound stubborn, but did you guys watch this part:

 

 

Look from 11.50 where he shows the completely streaked smaller part. After he redid it in a zip bag with liquid peroxide it came out looking just fine IMHO.... the problem is doing the huge cover parts like that and mentions he left it for now...

 

....oh and whatever you think of 8 bit guy, at least he's brave enough to show his mistakes, plenty of people wouldn't do that...

 

O well, I'm in the process of buying stuff to go and try it for myself.

Edited by Level42
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The Osborne case is very pale anyway: like the 800XL case, it's hard to irredeemably mess it up. Darker plastic is a different matter, and no: don't treat the brown XL bits. There's no point.

 

I melted a whole ST keyboard after trying the 8-Bit Guy's heat technique, presumably because I got the temps wrong. Adding more peroxide did not help. :)

 

8-Bit Guy was a tad complacent with the key caps. He'd never treated this kind of machine before so doing a test on the back of one key first might have been a good idea. Happens to the best of us, though. :)

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Yeah the heat technique sounds risky and only possible for really small things....

 

I like Klund1's idea of first applying the Creme with a brush but then spreading it with a roller.

 

It looks like the streaks on the Osborne were caused by using the brush....it seems key to have a very even layer of peroxide.

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It's funny how different "the same" products can be....

 

The upper keyboard belongs to the Mega STE I was kindly given by Fred recently (in return for some (de)solder and repair jobs). It was dirty and messy, but the case didn't seem to have any yellowing at all (the keys did a bit).

 

The lower keyboard I bought at an Atari fair in Germany....must have been 1992 or so...it's clear it's from Germany as it has a German key config (the top one is U.K. config, that was sold here in The Netherlands...) anyway, I used this with my 1040STFM which I had built into a tower case so I needed an external keyboard. I think I must have used it until 1996 or so when I entered my dark-side years of PC use.... after it got in disuse I put it into a metal filing cabinet with those large drawers that normally hold files in offices....so there's was no sunlight ever reaching it for 20 years or so....and yet.....it yellowed like crazy !

 

Fred already retrobrighted the case and the keys are up next....quite a difference :)

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Edited by Level42
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If the sun's very intense, the process can start happening very quickly and you need to be ready to clean off dried peroxide. It's like painting stuff: better several light coats than one heavy one. :)

 

The level of discolouration over time depends on bromine content and storage conditions. Ultimately, I hand-picked machines from my own collection for regular use which showed little or no signs of discolouration in the first place. The rest stay in the cupboard and are (re)treated as needed. I bought a replacement XE keyboard from Best some years ago and it turned yellow pretty quickly, while the keyboard from another machine in the collection never went yellow in thirty years, so that one got promoted. :) Likewise, I moved the pile of STs the other days while working on the walls here and noticed that the 4160STe I treated years ago is yellow again, while the 1040ST I never touched has a case and keyboard which look as good as new.

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or you can use dollar store liquid peroxide boosted by oxy clean and leave it in the sun all day without having to worry about it

 

blogentry-35237-0-12001300-1503890714_th

 

ps level 42, peroxide is a bleaching agent

 

 

Hydrogen peroxide is a chemical compound with the formula H
2O
2
. In its pure form, it is a pale blue, clear liquid, slightly more viscous than water. Hydrogen peroxide is the simplest peroxide (a compound with an oxygen–oxygen single bond). It is used as an oxidizer, bleaching agent and antiseptic. Concentrated hydrogen peroxide, or "high-test peroxide", is a reactive oxygen species and has been used as a propellant in rocketry.[4] Its chemistry is dominated by the nature of its unstable peroxide bond.

 

Edited by Osgeld
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Sun ? What is sun ? Nah...we need artificial UV beams im in our little corner of the world....

 

Osgeld you're absolutely right......but I was more thinking about chloride as bleach...

 

So....I bought all this stuff today.....

 

 

 

Note the only correct way to spell Aluminium ! :D

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Edited by Level42
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doesnt matter, a strong concentration of bleach can and will change color of things, so when yahoo's like the 8 butt guy add nasa approved rocket fuel crap on their victims and set it in the desert sun for hours on end its going to attack the color

 

why do you think they use it in hair salon's, it isn't cause it doesn't effect the natural color of hair

 

:D

Edited by Osgeld
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I hope this stuff will be OK....bought at the local hair-stuff shop....

 

I have to credit Fred M for all this because I simply looked at his set up and method :)

 

First a hole in the bottom of the plastic basket (or whatever the English name is for those things) for the lamp holder. I made sure to have it as far up as possible.....the higher the lamp the more space under it I think....

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doesnt matter, a strong concentration of bleach can and will change color of things, so when yahoo's like the 8 butt guy add nasa approved rocket fuel crap on their victims and set it in the desert sun for hours on end its going to attack the color

 

why do you think they use it in hair salon's, it isn't cause it doesn't effect the natural color of hair

 

:D

Yeah.....but in my way of thinking everything would be affected by what I call a bleaching process. The Retrobright idea is that it only attacks the yellow-brown colors but not the original color of the plastic. How else would a partially discolored item turn out even colored after the process ?

 

Remember that in hair salons they don't add the UV light....

 

But anyway.....on with the preparations....how to fix the aluminium foil to the box ?

 

1) Thought about that I had still this spray glue around....I tried out a small part of foil on the cover of the box and it worked great.

 

2) Next I covered the lamp holder with an old spray can cover...really don't want any glue there....

 

3) tried to get the foil on as straight as possible....not easy....but good enough

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1) While I was at it, and since the box came with a lid, I figured the lid could be used as a reflective bottom for the box to stand on....the more reflection the better and the more the UV gets spread around the object the better too.....I gues.....in most cases.

 

Could even use some stands to put some items on if I need to retrobright them "all around" I guess....

 

 

2) Next was connecting a wire with mains plug to the lampholders wiring and screwing in the lamp....

 

3) Then it was power up time.....the lamps seemed to need some breaking in as the glow only started from the beginning of the tube, after a while the tube was completely lit and very bright....I made sure not to look into it though....well as much as possible....

 

4) all set and ready to go !

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My first guinnea pigs.......compare the color of the 1020 with my most precious 600XL, which doesn't show the least sign of yellowing....the other "victim" is my very comfortable ST compatible mouse.....on which I hacked an original Atari ST mouse lead because it was a lot shorter and less trouble when connected to the STE keyboard....

 

And now....we wait....put it next to the radiator in my kitchen so it's nice and warm :)

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Edited by Level42
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Ah the good old Osborne. The one at my school was probably the first computer I ever touched and wrote some BASIC on :)

 

I can get a Kaypro from someone who bought it new BITD but.....why would I ....yes it's cool but....you know.....no....really don't need it....no....really..... :)

 

Yeah I still think this process can't be overdone but I'm just a few hours into Retrobrighting so who am I to think that :D :D

 

My first test has been running for about 5 hours now and I do see some difference (I think) but it sure is not a quick process....... I'm really interested in that version 8 bit guy used with only heat..... Was thinking about adding some heating under the box/cover I made.....I have a feeling the people who put this stuff in the sun in warmer areas of the world have the combination of heat and UV....

 

Oh and I guess I need to drill a few holes on the top....the box is SO closed up that whenever I take a peek under it, there's really a bad smell of the peroxide....I'm almost afraid to open it for fear of a gas explosion....... well if I'm going to add heat I'll need it to do a bit of conveying anytway, so some air holes around the (now) lower side of the box and some on top.....

 

By the way, do I need to apply new peroxide a few times during the process of is just one time enough ? I did cover everything with cling film....

Edited by Level42
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