Undoing marble effect after retrobrighting? Heat shielding the badges?

[Gordon Fecyk]

I managed to restore two Commodore 64s, one of them in a strange Australian-made case. These machines were left in pretty poor conditions, and as a result they were both yellowed and faded at the same time.

 

I used a peroxide cream, plastic wrap / cling film and UV light to remove the yellowing. This worked, but left a marbling effect on the cases. Then I remembered YouTube videos of stadium seats being restored using flame throwers:

 

 

To test this I tried a long stem lighter on a 1541 drive case that I treated similarly. It wasn't as badly yellowed or marbled after peroxide treatment, but it did have several bright spots on it and the lighter was able to remove these bright marks without damaging the case texture. I'd rather use one of those wood-working torches or maybe a strong heat gun.

 

If I try this on the 64 cases, I might melt the badges and labels, which are in good shape. Is there some kind of reflective material I could apply to the badges that I could easily remove afterward? I should have thought about not applying new labels right away, but they're attached now and I might damage the new labels if I try removing them. 

Edited December 21, 2023 by Gordon Fecyk

[+OLD CS1]

I would remove the badges and labels.  It will take a little heat to soften the adhesive holding them in place, and care will be necessary to prevent bending the badges and stretching or tearing the labels.

 

Godspeed.

[Boschloo]

2 hours ago, Gordon Fecyk said:

 

I used a peroxide cream, plastic wrap / cling film and UV light to remove the yellowing.

This worked, but left a marbling effect on the cases.

I love the Aussie Slimcase64, I wish I had one. If you don't want it, I'll be happy to buy it. Let me know.

That being said, you should not use the cream and cling method unless you first run the case through the dishwasher (turn off heated dry) for three hours. Any dirt invisible to the eye will cause the marbling effect. I prefer the immersion method. It depends on how much you are willing to invest in this project. My preferred method involves UV lights from Amazon, immersed console shell in clear plastic tub, and Salon Care 40.

[Gordon Fecyk]

20 hours ago, Boschloo said:

That being said, you should not use the cream and cling method unless you first run the case through the dishwasher (turn off heated dry) for three hours.

Interesting you bring this up. I did exactly this, and the dishwasher did a phenomenal job cleaning the cases. Also used a pair of 150 W LED UV lights. I would have used my peroxide in submersion, but I've had marbling happen even with that method. The yellowing was so bad and my peroxide stock was very low, so I had to adapt. You'll see once I put the video together.

 

I also already had to replace the original badges on the breadbin. An overseas eBay vendor sells replica badges using vinyl. I can remove them if needed.

 

[Boschloo]

36 minutes ago, Gordon Fecyk said:

The yellowing was so bad and my peroxide stock was very low, so I had to adapt.

Why not do it again, this time submerged? It's what I'd try...the second retrobrighting would just remove the yellow streaks, right?

[Gordon Fecyk]

6 hours ago, Boschloo said:

Why not do it again, this time submerged?

I did this too, partially to rinse off the cream and also partially to even out the effect. The cream dissolved into the water to get to about 5% peroxide solution to finish things of. All of the yellowing is removed, just need to work on the marbling. 

 

I won't be following this thread for a couple of days, but I'll post a follow-up once I've had a chance to try some kind of heat treatment. The 1541 case's white spots disappeared nicely with a little bit of heat. I also have way too much footage to sort through but I want to put together a video. There was a lot more going on than retrobrighting.

[+OLD CS1]

2 hours ago, Gordon Fecyk said:

There was a lot more going on than retrobrighting.

If there is no video with a flame thrower, I ain't watching.

[Boschloo]

Another day, another C128 in the dishwasher. This time I removed the keyboard from the case. It's in the backrow on the bottom. This is because I'm retrobrighting the case tomorrow. All the keycaps are in the side baskets. You can see the spacebar sticking out.

I'm hoping not to get any marbling. For that purposes I added a cup of baking soda to the bottom of the dishwasher. You know, just in case.

Edited December 24, 2023 by Boschloo

[Boschloo]

On 12/22/2023 at 4:04 PM, Gordon Fecyk said:

I did this too, partially to rinse off the cream and also partially to even out the effect. The cream dissolved into the water to get to about 5% peroxide solution to finish things of. All of the yellowing is removed, just need to work on the marbling. 

 

I won't be following this thread for a couple of days, but I'll post a follow-up once I've had a chance to try some kind of heat treatment. The 1541 case's white spots disappeared nicely with a little bit of heat. I also have way too much footage to sort through but I want to put together a video. There was a lot more going on than retrobrighting.

Funny coincidence but, I just accidentally ran into your video of your C128 restoration and the setup you have there is similar to mine. I hope we both get good results.

[Gordon Fecyk]

No flamethrower yet, but I want to explore that in the next episode.

(Video is still uploading as I post this reply.)

 

Edited December 26, 2023 by Gordon Fecyk
Paragraph spacing

[Boschloo]

20 hours ago, Gordon Fecyk said:

No flamethrower yet, but I want to explore that in the next episode.

(Video is still uploading as I post this reply.)

 

Gordon! Sell me that Aussie case, please!

[Boschloo]

On 12/21/2023 at 9:04 AM, Gordon Fecyk said:

I'd rather use one of those wood-working torches or maybe a strong heat gun.

I was thinking of you yesterday when I was distraught over marbling in a retrobright-gone-wrong situation. So I took out my hot air reworking station and went at an orange stain with the hot air pencil. It didn't change the color of the stain but I had the wind speed too high and it drew a bead of plastic from the case. Luckily this was on the bottom. 

[eightbit]

On 12/23/2023 at 8:21 PM, Boschloo said:

I'm hoping not to get any marbling.

 

You won't if you do it right and not use the "cream method". I have no idea why people are still doing that.

 

Just use Salon 40 Clear Developer mixed with water (I used a 50/50 mix) and submerge the piece on a sterilite tub. I covered the top just so that leaves or whatnot would not get inside.

 

That's it. No "spreading the cream" around every 30 minutes, no BS and no marbling. Which is specifically caused by the piece being wrapped up in cling wrap by the way.

 

 

This is the top half of C128 I did around 3 years ago. This was a pretty bad case scenario as this case was not very evenly yellowed to begin with. But it came out OK. I have had much better results where the case were evenly yellowed. I have more pictures of other machines I have done somewhere...

 

 

Edited January 15 by eightbit

[Gordon Fecyk]

A moderate heat gun (1100 W) removed marbling from a 1541 case that was exposed to the elements and was also faded by sunlight at the same time. It also re-darkened some of the plastic, which I was able to undo with more retrobrighting. The end result still had the odd blemish but those blemishes resembled typical wear from indoor use, as opposed to being exposed to the elements for decades.

 

I repeated this on the breadbin 64, which removed the marbling but also re-yellowed the case. I ran out of peroxide, or I would have redone this one too. Since it's the same plastic as the 1541 I redid, I think this is fixable.

 

The whole cream / cling film thing was trying to conserve what peroxide I had left, plus it seemed to be needed for the really yellowed cases I was dealing with. I submerged a C128 but it still had marbling. I submerged a PET style VIC 20 but this left a yellow streak on one side. The cream and cling film helped me deal with a spot treatment in this latter case, and no marbling.

Edited January 15 by Gordon Fecyk

[roots.genoa]

You do what you want with your systems, but it's important to understand that the yellowing of plastic can't be reversed. It's a chemical reaction at a molecular level. Retrobright is only temporarily bleaching the plastic, and it actually damages it in the long run.

[Boschloo]

1 hour ago, roots.genoa said:

Retrobright is only temporarily bleaching the plastic, and it actually damages it in the long run.

I don't see a lot of people saying "Oh no! The computer I retrobrighted so well 10 years ago looks like crap, now!"

 

Where are the long term studies?

[+OLD CS1]

1 hour ago, Boschloo said:

I don't see a lot of people saying "Oh no! The computer I retrobrighted so well 10 years ago looks like crap, now!"

 

Where are the long term studies?

https://deskthority.net/viewtopic.php?t=6084

[+OLD CS1]

11 hours ago, eightbit said:

[...]no marbling. Which is specifically caused by the piece being wrapped up in cling wrap by the way.

One night, a friend of mine thought it would be funny to Saran Wrap my 1979 Chevy Monza.  As it was my day off, I slept in.  Around noon or so I found my car in its newly-wrapped configuration, and also that the moisture in the air at the time of its special event was trapped under some of the wrap.  The morning sun heated that moisture, which then found itself trapped in the plastic wrap and, unhappy in its inescapable predicament, took out its frustration on the paint of my car.

 

Not so much marbled as stripped in odd geometric shapes.

 

This experience alone has led me to be critical of the plastic wrap and peroxide cream method.

 

BTW, I did get my revenge upon him.  He was so very pissed.  He did not speak to me for months.  It was glorious.

[eightbit]

Yeah, I don't make it a habit of retrobrighting personally. I tried it with the C128 (because it looked BAD in person) and with a really nasty VIC-20, but that's about it.

 

I don't really have anything else that has yellowed badly except for some old Altec Lansing PC speakers.

 

There are probably ways to keep the plastic from re-yellowing such as applying some sort of clearcoat on the plastic after retrobrighting. But there I would think it would ruin the original texture. EDIT: The article OLD CS1 posted actually has Tez speaking about how he thinks that will not even help.

 

I'd say do it only if you really have to or don't care if you may be weakening the plastic, otherwise leave it alone and consider the yellowing as a fine patina on a well lived console/computer. 

Edited January 16 by eightbit

[+OLD CS1]

47 minutes ago, eightbit said:

I don't really have anything else that has yellowed badly except for some old Altec Lansing PC speakers.

OMG, I have a yellowed set of those, too.

 

As has been pointed out many times, but I think merits mentioning here, the yellowing is caused by a chemical reaction of the bromine used as a fire retardant and the base polymers of the ABS plastic.  It is inevitable.  Not all plastic batches are the same, so yellowing is different across even the same product.  There is a lot of conjecture as to what accelerates or retards this yellowing.  In my experience: age has been enough for some devices; fluorescent lighting, as evidenced by shadows left by the light (thus my switch to halogen lighting); acids in cardboard have been disastrous.

 

Of course, the yellowing is bad enough, but some plastics become brittle or even crumble.  I have had this happen with a couple breadbox Commodore 64s.  Later plastics from the 90s, were no better.  I recently had a Zip Plus drive (ca. 1997) which just crumbled in my hands a couple of years ago, among others I have come across.  I have a printer which has become brittle with its age, including some of its primary drive parts -- very sad.

 

I would like to lament the lack of foresight given to the uses of these plastic amalgamations, but then I must consider we are maintaining stuff well past their life expectancy.

 

EDIT: As an afterthought to this, I have used Krylon on an Amiga 600 case before.  It looks very nice, but that is not stopping the aging underneath.

[Grimm1966]

I have heard that people have tried a UV protectant (Armor All?) thinking that it would help to protect the plastic from yellowing.  Has anyone had any luck with that?

 

[+OLD CS1]

3 minutes ago, Grimm1966 said:

I have heard that people have tried a UV protectant (Armor All?) thinking that it would help to protect the plastic from yellowing.  Has anyone had any luck with that?

It would only prolong the inevitable.  A UV protectant cannot stop the chemical reactions happening within the plastic.  Some chemicals might even catalyze the process.

 

That said, I bet it would make the plastic nice and shiny.