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Atari 800 Restoration. Retrobrite or paint.


gs80065xe

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10 minutes ago, gs80065xe said:

What is the preferred method of restoring the case on the Atari 800? Is it safe enough to retro-brite? Or would spray painting be Krylon camouflage kaki better and safer option?

I haven't yet tried it myself on old plastic, however my father in law has used it for the plastic on this car's headlight lenses with success.  Perhaps try it out on a inconspicuous spot:

 

https://helloglow.co/natural-oven-cleaner/

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I've done a 400 and an 800 recently using the "retrobrite" method.  Just get some salon creme developer like this:

https://www.sallybeauty.com/hair/hair-color/developer/40-volume-pure-white-creme-developer/SBS-320828.html

Clean the 800 thoroughly and brush the developer evenly on all surfaces, then leave it in an evenly-lit room for a day or two.  You can put it outside if you can't get much sunlight inside the house, but then you have to deal with dirt, animals, etc.  You can also use some indoor UV lights if you want to get fancy, but it's almost no effort and very little risk to try it indoors first to see if that works.  If you get a bit of desired effect but not enough, just do it again.

 

@Colleton tried this method recently and had good results, and his 800 was more severely yellowed than mine:

 

I'd say using paint runs a very high risk of ruining the case.

 

 

Edited by jamm
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43 minutes ago, gs80065xe said:

What is the preferred method of restoring the case on the Atari 800? Is it safe enough to retro-brite? Or would spray painting be Krylon camouflage kaki better and safer option?

NEVER, ever paint (!)

 

It is not needed, at all.

 

You will be surprised what 18% Peroxide cream (like Clairol) + just 1-2 hours of sunlight (around 3:00pm) will accomplish...

 

Check every 15 minutes, keep cream fresh/wet (with brush), and just make sure internal + external colors are close enough (only apply cream on the external surfaces). Use gloves to protect skin.

 

;-)

Edited by Faicuai
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19 minutes ago, gs80065xe said:

OK. I'll try The Peroxide option. Just need to see if the local Sally's is open. (City is under a Quarantie). If not, guess I'll order it. How much does a bottle cover?

 

 

I bought one of those 16oz bottles and I think I've only used about 1/3 of it on two machines.

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  • 3 weeks later...

The peroxide cream finally arrives just as the sun disappears behind the clouds. Looking like next Thursday before it comes out again. And suggestions? Is it as simple as disassemble down to the plastic shell. Apply the cream. Wrap in plastic wrap. And sit it in direct sunlight for several hours.

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35 minutes ago, gs80065xe said:

The peroxide cream finally arrives just as the sun disappears behind the clouds. Looking like next Thursday before it comes out again. And suggestions? Is it as simple as disassemble down to the plastic shell. Apply the cream. Wrap in plastic wrap. And sit it in direct sunlight for several hours.

I think wrapping it in plastic increases the likelihood of getting uneven patterns or streaking.

As a first pass: Just brush the cream evenly over the entire surface of the machine. Yes, it's going to dry out, but it's fine.  If you have a room indoors with decent natural light - not direct sunlight - leave it in there for a couple of days.  Wash the cream off and check on your results.  Rinse/repeat as necessary.

 

If you find that the plastic is very yellowed and this method isn't improving things quickly enough, you can always move to the more elaborate/involved options after you try this.

 

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You want to keep the plastic cool, put a fan on it outside or do it when sunny and breezy. Scrubbing the case can be a real winner, you would believe how much yellow can be washed away... sometimes it turns out to be tar or staining from a smoker or fireplace stoves user.... wash the dinge away...

Edited by _The Doctor__
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Retro Bright is the quick way.  But there was a post on here about just leaving plastics out in the sun un treated also working and I can confirm it does work, but takes longer.  I did my childhood 1979 Millenium Falcon.  I was worried about being able to get the retro brightening process done evenly since the surface of the falcon has so many recesses.  I disassembled the ship cleaned it thoroughly, then left the outer shell sitting on my pic-nic table in the back yard for about 2 week last summer.  Its  turned out very nice and evenly whitened

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5 hours ago, Sugarland said:

Using plastic wrap greatly increases the chance of streaking (ruining) the case's appearance. I think (!!) the key is to keep reapplying the cream. However I also had great results with plain sunlight. Heat is bad for the case, btw. 

I never had an issue when wrapping in plastic wrap, key is to keep the surface wet as you said.

I'm now only using sunlight though, much safer and works well 

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17 hours ago, _The Doctor__ said:

You want to keep the plastic cool, put a fan on it outside or do it when sunny and breezy. Scrubbing the case can be a real winner, you would believe how much yellow can be washed away... sometimes it turns out to be tar or staining from a smoker or fireplace stoves user.... wash the dinge away...

Absolutely, a thorough and deep wash first (with some clorine or mild / medium bleach action, in cold place) will take away all the stuff that you DO NOT want to bake-in with peroxide and sunlight (!)

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9 hours ago, Sugarland said:

Using plastic wrap greatly increases the chance of streaking (ruining) the case's appearance. I think (!!) the key is to keep reapplying the cream. However I also had great results with plain sunlight. Heat is bad for the case, btw. 

Dead-on!

 

Constant monitoring/ re-application of cream (covering evenly and remaining moist), plus good sunlight, will get the job done anywhere between 1 to 4 hours, while keeping plastics' temperature as low as possible. They are already old enough.

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I have a few remaining bits of A8/ST kit that did not get disposed of with my big purge last year, one of which (an 800) I cleaned up the retrobrite way about 18 month ago.

 

BUT I have found it has started to yellow again - and it has been in a sealed box since I cleaned it ?

 

sTeVE

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A recent post in the Atari 8-bit computers group on Facebook is giving me second thoughts. The poster says the yellowing protects the plastic from further chemical changes. And the more you retrobrite, the deeper the damage goes. That leads to making the plastic brittle.
 

I thought I read somewhere the yellowing was a chemical reaction of the fire retardant and UV light.

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12 minutes ago, gs80065xe said:

A recent post in the Atari 8-bit computers group on Facebook is giving me second thoughts. The poster says the yellowing protects the plastic from further chemical changes. And the more you retrobrite, the deeper the damage goes. That leads to making the plastic brittle.
 

I thought I read somewhere the yellowing was a chemical reaction of the fire retardant and UV light.

 

There are a lot of different opinions about this and what exactly causes the yellowing.  I've heard about the fire retardant, also, which seems like a reasonable enough explanation.

 

I can tell you I've now done the 'easy' process I described above on four different machines and don't notice any difference in the feel of the plastic.  I wouldn't do it 10 times, but I can't imagine that even doing it a handful of time would make a difference.  I don't know about some of the other methods, and I also suspect there's a bit of variation in the plastics and what condition they happen to be in.

 

YMMV

 

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2 hours ago, gs80065xe said:

A recent post in the Atari 8-bit computers group on Facebook is giving me second thoughts. The poster says the yellowing protects the plastic from further chemical changes. And the more you retrobrite, the deeper the damage goes. That leads to making the plastic brittle.
 

I thought I read somewhere the yellowing was a chemical reaction of the fire retardant and UV light.

 

Are they referencing sunlight brightening or the hydrogen peroxide method?  I suspect the latter. I've heard several times that peroxide brightening makes the plastic more brittle. It may depend on how it's done, too.

 

FYI apparently compact fluorescent lights greatly accelerate the yellowing. It's bad light in the wrong frequency range.  LED and incandescent lights are fine.  I've never had yellowing plastics with either of them.

 

 

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2 hours ago, gs80065xe said:

A recent post in the Atari 8-bit computers group on Facebook is giving me second thoughts. The poster says the yellowing protects the plastic from further chemical changes. And the more you retrobrite, the deeper the damage goes. That leads to making the plastic brittle.

 

Ehhhh... nobody really knows *anything* for sure about any of this process, to be honest. Or rather, they think they do, but there's all sorts of conflicting "knowledge". All you can say for sure is what's been *demonstrated*. This is how science works - you come up with a hypothesis, and then you test it. But I have not seen a single demonstration of plastic becoming more "brittle" through retrobrighting, anywhere. And I have not noticed this myself in any of the stuff I've retrobrighted.

 

There are a lot of myths about retrobrite (aka peroxide bleaching) out there, and this seems like one of them. I have tested various methods of retrobrighting myself; a lot of what you see on the internet is just plainly untrue (ie. my actual tests haven't backed it up), and many other things people say have no evidence either for or against but don't really pass the smell test (ie. the "it makes things more brittle" argument; all my stuff seems fine to me).

 

The two arguments I often make about retrobrighting is that it's often not worth it because a) you don't really know what the original color even was, especially if you're relying on old magazine ads or videos or something, and you're never going to hit it just right anyway, and b) stuff often yellows again pretty quickly. And both of those arguments are backed up by evidence. But the first argument, at least, applies even more to painting.

 

I sometimes think it's worth doing and sometimes not. If I had something I'd recently bought that was *clearly* yellowed, I'd probably do it. That's why I did it to my 520ST, and that thing came out *beautiful*. It wasn't quite what I think was its original color, but it was *clearly* an improvement over what it looked like when I got it. On the other hand, I've left my Apple IIc banana yellow, because all that yellowing is mine (I've had that computer since 1985), I'm not convinced I'd ever get it close to what I remember its original color to be, and it seems to yellow so easily that I'm sure the yellowing would return very quickly. I tried retrobrighting my Apple IIgs keyboard and it has already re-yellowed.

 

But I would never paint anything. Most of these things were never painted and it's just *really* obvious if someone paints something that wasn't originally painted.

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3 hours ago, gs80065xe said:

A recent post in the Atari 8-bit computers group on Facebook is giving me second thoughts. The poster says the yellowing protects the plastic from further chemical changes. And the more you retrobrite, the deeper the damage goes. That leads to making the plastic brittle.
 

I thought I read somewhere the yellowing was a chemical reaction of the fire retardant and UV light.

Geez... There is no such "enhanced" protection from yellowing.

 

The ONLY thing that protects plastics are the environment (and variables) surrounding it: Stable / ambient temperature, low humidity, air purity or vacuum, and isolation from other (possibly) reactive compounds like styrofoam, synthetic packaging-materials, etc. 

 

And even under the above conditions, yellowing may still be possible to some degree... at which point it may well be inevitable.

Edited by Faicuai
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On 4/20/2020 at 5:41 PM, _The Doctor__ said:

Heat is the enemy in storage, so is Styrofoam, so make sure to bag it with non degrading plastic bag, else styro may interact and stick to stuff... certain clear plastic bags turn stick and yellow, which does the same to whatever is inside them...

 

 

It was in a sealed, opaque, plastic storage box, not touching the sides, kept indoors away from any direct sunlight and sat on a cotton pad, not much else I could do really to protect it ?

 

Interestingly I have an STE that has in one area gone completely brown - not the areas in contact with the foam packing (it is in an original box) - but along the leading edge of the unit - looks very strange!

 

I figure you have old equipment, it won't look new after nearly 40 years...

 

     sTeVE

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