The truth about Retr0brite – busting myths with science…

[Hugo Holden]

Not to deviate too much from the Retrobrite controversy, but the paint method I suggested shades the plastic from further sunlight damage, helping to preserve it and in addition, the opportunity can be taken to repair chips and cracks and damaged plastic areas prior to the coat giving a much better cosmetic appearance and in addition to this, because of all the shades available with the Dupli-Color, you can have the plastic any shade of white to off white, or practically any other color you like.

My main goals are: 1) preservation of as much of the original plastic material as possible, perhaps extending its life and 2) having an excellent cosmetic appearance.

I just cannot buy into the notion that photon based bleaching or chemical bleaching of the surface plastic meets the "preservation" directive, even if the optical appearance is improved (it is just my personal view).

On the other hand all the rules are different for metals, and rusted metal surfaces benefit significantly for serious electro-chemical treatments involved removing the rust & corrosion prior to re-electroplating them. I specialize in the restoration of vintage TV sets, this article shows before & after chassis photos:

https://www.worldphaco.com/uploads/HMV__904_ARTICLE.pdf

 

[Chuck(G)]

It wasn't uncommon for some postwar TV chassis to be copper-over-steel plated. I've worked on a few myself.

 

[thenzero]

I specialize in the restoration of vintage TV sets, this article shows before & after chassis photos:

https://www.worldphaco.com/uploads/HMV__904_ARTICLE.pdf

That was a very enjoyable article, thanks for posting that.

 

[vol.2]

Painting or otherwise coating vintage plastics is a very good path to explore. As Hugo noted, the coating will fill the cracks in the surface of the plastic. Also, if chemically compatible, the coating will melt the exterior of the plastic a tiny bit and strengthen the oxidized shell by melting together voids and bonding it.

However, I don't believe that every kind of plastic, or every mix of ABS is going to have the same response to a single variety of solvent-based paint. I think the solution has to be a home-brew that contains a blend of stuff that is designed to do this. If done right, it could even be applied clear over retrobrighted plastic to create a resilient exterior finish, or be colored with tiny amounts of pigment to subtly refresh a yellowing PC case.

 

[thenzero]

Any worry that the plastic might continue to degrade undetected beneath the paint (and be harder to access due to being coated in paint)?

 

[Chuck(G)]

With regards to plastic degradation, go to museum people. The Getty Institute has many papers on the subject..
But you can start here

 

[vol.2]

In theory, the coating and melting together of voids and micro-fissures would create a protective layer to keep new oxygen from further degrading the inside, but it's never going to be perfect. It might also be helpful to coat the inside.

If the oxidation is being caused by chemicals intrinsic to the ABS, and the presence of oxygen isn't necessary to cause it (I think it most likely is), then there is nothing you can do to stop it and it will eventually just fall apart, regardless of how much access you have to it.

Then again, there could be some kind of treatment for it that will neutralize that process. Old nitrate film negatives can be chemically treated to slow and/or stop the combusting process that happens when they are left to deteriorate. Perhaps there is some chemical dip that can stabilize ABS?

I'm not a chemist (but I did work in a chemical engineering lab running experiments for some years), so someone else is going to have to comment on how possible any of this is. I do believe that, with enough work, both a better coating solution and a stabilizer mix could be created. I can't comment on how much work it would take, but it's not trivial.

 

[thenzero]

With regards to plastic degradation, go to museum people. The Getty Institute has many papers on the subject..
But you can start here

Wow great article.

As an aside, I love the Getty. The study they did after they found out that their kouros statue (on display at Getty Villa LA last time I was there) might be fake was absolutely fascinating to me.

 

[Chuck(G)]

In any case, caution is advised. I'm reminded of the "wisdom" of storing acetate-base film in airtight containers. Turned out to be exactly the wrong thing to do.

 

[thenzero]

Presumably the paint helps protect against UV mediated/activated degradation as well.

 

[Chuck(G)]

My first impulse would be to go with a water-base acrylic. We don't know what the solvents in VOC-based paint will do to plastic, long-term.

 

[vol.2]

I was never advocating the use of any of these methods without proper testing through controlled experiments.

My first impulse would be to go with a water-base acrylic.

AFAIK, water based acrylic won't adhere to (most) plastics. It will coat it, but it's not going to bond to it and will be easily ablated. That's not an issue if you're painting a DnD miniature, but it's going to create an ugly mess if you coat a big PC case and it gets any action at all. It can also just peel off over time with age, especially on large flat areas. Also, it will require a thick coat that will mask the surface patterns created by the original plastic molds.

We don't know what the solvents in VOC-based paint will do to plastic, long-term.

VOC-based paints for plastics are widely used and have been for decades.

 

[thenzero]

I was never advocating the use of any of these methods without proper testing through controlled experiments.

I hope I didn’t imply that you did…didn’t think you were.

VOC-based paints for plastics are widely used and have been for decades

Was coming in here to make the same point. I’m sure there’s actually a good bit of data on it, although I haven’t actually looked for it yet.

 

[Chuck(G)]

With the lights out and the curtains drawn, you can't tell the difference anyway.

 

[Agent Orange]

FWIW I've used black acrylic spray paint on hard and floppy face plates and blank-off plates for years and never had a serious mismatch, chiping, or peeling problem. I even did the CDROM cover plate in drab dark green to match a PC case and it turned out fine. also, if I need to to do a 'putty' colored PC case or part I know where to get something very close at Walmart. Painting is the way to go for me. I think this business of scalding plastics is these various chemical is detrimental to their long term longevity.

 

[SomeGuy]

FWIW I've used black acrylic spray paint on hard and floppy face plates and blank-off plates for years and never had a serious mismatch, chiping, or peeling problem. I even did the CDROM cover plate in drab dark green to match a PC case and it turned out fine. also, if I need to to do a 'putty' colored PC case or part I know where to get something very close at Walmart. Painting is the way to go for me. I think this business of scalding plastics is these various chemical is detrimental to their long term longevity.

I'm curious what kind of paint you are thinking of. I used some rust-oleum "Satin Fossil" on a very badly discolored and stained Apple II Plus clone case and it came out acceptable looking. (I did have to use some peroxide to lighten up one side a little. Even after that, and through the paint that side looks a hair darker). Not the color I would use for a PC case, though.

 

[Chuck(G)]

Paint made specifically for plastics can have chemical etching agent to provide something for the paint to grab onto. I've heard that Krylon Fusion is a good choice, but I don't know the range of colors. Once you've got a good primer coat, you're probably good with most anything as a top coat. But surface prep is everything. Try painting a hunk of ABS sewer pipe to see if the paint resists flaking and chipping.

 

[Agent Orange]

I'm curious what kind of paint you are thinking of. I used some rust-oleum "Satin Fossil" on a very badly discolored and stained Apple II Plus clone case and it came out acceptable looking. (I did have to use some peroxide to lighten up one side a little. Even after that, and through the paint that side looks a hair darker). Not the color I would use for a PC case, though.

No big mystery. We did a thing on this very subject about a year or so ago. It's spay paint that is plastics friendly and you can get it at Walmart. I'll try to get you the exact name and spect tomorrow. As a matter of fact I even had the number of the paint and it it came pretty close, if not the same as IBM's. It's here on some thread but I can't remember where.

 

[Chuck(G)]

Probably RustOleum "Painter's Touch 2x Ultra Cover". I've got a couple of cans of it here.

Nice range of colors

Most big-box stores carry it.

Do I paint my stuff, you ask? Yes, in some cases. For example, when I receive a floppy drive with a shattered bezel. I can piece the bezel back together, but small pieces may be missing, so I fill those in with auto body filler, sand things smooth and go with the rattle-can. Looks fine.

 

[Agent Orange]

I'm curious what kind of paint you are thinking of. I used some rust-oleum "Satin Fossil" on a very badly discolored and stained Apple II Plus clone case and it came out acceptable looking. (I did have to use some peroxide to lighten up one side a little. Even after that, and through the paint that side looks a hair darker). Not the color I would use for a PC case, though.

Here's 2 threads:

https://www.vcfed.org/forum/forum/m...-data-yd-580-bezel-have-at-grey-need-xt-black

https://www.vcfed.org/forum/forum/g...ing-for-apple-ii-and-apple-ii-plus-only/page4