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The truth about Retr0brite – busting myths with science…

I have been using the Dupli-Color spray (a very old product), for metals and plastics and restoration jobs, for how long ?.......thinking back I first used it when I was about 15 years old, so about 45 years now. I have a lot of experience with it. I have some objects that I sprayed over 30 years ago still, look unchanged. The paint is not only excellent for every plastic I have used it on, it is quite UV resistant, being designed for automotive use. Indoors, it seems ageless. I cannot see any obvious need to go looking for an alternative paint and it comes in nearly every conceivable shade & clear.

PS: the clear Dupli-color is superior on Brass to any other lacquer I have tried, very adherent, have a look at this radio with brass escutcheons that I restored over 15 years ago, they still look the same today, so the clear provides a very waterproof / moisture proof layer too:

https://www.worldphaco.com/uploads/THE_GREBE_MU-1.pdf
 
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If you want really shiny brass, after you're through buffing with rouge, good old nitrocellulose lacquer gives the best results. Dangerously explosive, however.

I speak from experience, having spent lots of time in the "pink cloud" with brass musical instruments... :)
 
Chuck(G) said:
If you want really shiny brass, after you're through buffing with rouge, good old nitrocellulose lacquer gives the best results. Dangerously explosive, however.

I speak from experience, having spent lots of time in the "pink cloud" with brass musical instruments... :)
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I have lots of nitrocellulose lacquer, in spray cans, from the Luthier Supplier Stewart McDonald, I used it for electric guitar restorations, a couple of my guitars:

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

Stewmac also has interesting engineering materials & tools that find other applications outside guitar restorations, one is their Tortoise shell scratch plate material, I used this as the front panel for a 1920's style vintage amplifier:

https://www.worldphaco.com/uploads/UX-171-A_Class_AB1_push_pull_amplifier..pdf
 
Different suppliers for me--Allied, Strege-Wuttke, Ferree's... Less woodworking and more industrial arts. Don't do it much anymore--life's gotten too busy. Lacquer supplier is Nikolas; perhaps their formulation is different from "guitar lacquer"; I have no idea.
 
Chuck(G) said:
Again, I'd want an explanation why two pieces of identically colored plastic on a system can exhibit yellowing differences, even when adjacent to one another.

No, we're a long way from "truth"--and that word in today is particularly loaded, what with fake cures and protocols being shamelessly promoted by people in the public eye--who have no business doing so. How about the "truth" of hydroxychloroquine or Ivermectin as a cure? Various governments have bet the house on those with disastrous effect. How many needless deaths have occurred because someone claimed to have the "truth"?

We don't know the TRUTH about the causes and the retrobright "remedy". All we've got is some anecdotal evidence.

Show me mass spectrograms, photomicrographs, detailed chemistry and I think that we'll be closer to the "truth".

Until then, we're just messing around with the Phlogiston theory.

I commend Jeff for his hard work and diligent efforts, but I don't think we've got the "truth" yet.
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Because the plastic is NOT identical. They could be from different batches, with different brands of bromine containing flame retardant added, etc. I actually laid out the whole path from where color come from, what causes yellowing and what effect bleach has on the yellow color. All of these individual subjects have been well researched and I included multiple papers for your perusal in the file set which is available for all do download. If you want to take the research further than have at it. I made my source material available.

Please keep your political views out of it. Nobody cares about your politics...
 
Agent Orange said:
Bromine is/was used as a fire retardant in plastics back in the 80's. It contributes to the discoloration when it breaks down.
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Bromine is very unstable, in facts its oxides can't exist above 0C. It's only real contribution to yellowing is that some bromine containing flame retardants in some formulations of plastics will catalyze the oxidation that causes yellowing. Covered all of this in great detail in the video...
 
thenzero said:
p.s. there are academic papers that talk about the accelerating oxidation effect of bromine on plastics it is added to
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Yes, and I went into this in the video...sigh...I even added a paper about this very effect in the file set. I'm not sure how much more clear I could have been.
 
Jeff_Birt said:
Please keep your political views out of it. Nobody cares about your politics...
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Has nothing to do with politics--today we're beset by people claiming to have the truth, without any scientific data. I could well have used Laetrile as my demonstration case. I want to see the scientific evidence, not just conclusions drawn from anecdotes.

Chemistry, mass specs, photomicrographs, peer-reviewed papers get closer to the truth. If you can proceed inductively, that's even better.

Had you simply titled your post "Observations on the use of Retrobright", I would have no objection.
 
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I don't think there is enough interest in the scientific community about preserving old plastics to put the effort into doing proper research into it. For the most part the cars and computers (to name a few things made with plastic) are generally disposed of before the plastics can get brittle enough to worry about ( and few people care about yellowing).

Some research I think was done by car companies (or their suppliers) many years ago because of cracking dashboards on cars left out in the sun. It used to be very common for vinyl seats to crack along with dashboards and plastic parts in cars to turn into dust over time from direct sunlight and heat during the summer months.
 
The "Truth" if there ever is such a thing, is so far off on this plastics issue, I could not comment on the Retro-brite idea with any degree of certainty, except for the knowledge that I am fairly certain of; is that oxidation and bleaching processes, either chemical or light mediated, break chemical bonds, this is their method of action. And that sunlight especially is very long term destructive to many plastics, accelerating the decomposition.

So for my restoration projects with plastic housings, cabinets, the goal for me is a good cosmetic appearance and protection from more light exposure. So if the surface is damaged, aged and badly yellowed, this is the primary reason I went for the Dupli-color paint and avoided the two commonly used whitening methods, sunlight bleaching and Retro-brite products.

I'm sure when the plastic degradation processes are better understood, there probably, for each type of plastic, will be some "ideal method" but for now, like Chuck, I'm not convinced we know what it is.

To throw some humor into the mix, somebody once pointed out that the better scientific trials (in medicine at least) were double blind controlled trials, where both the investigators and the patients had no idea who was receiving the real treatment and who was getting the sham or placebo treatment.

But then somebody made a couple of observations:

1) That life is bad enough when even one person doesn't know what they are doing, let alone two.
2) The double blind methodology has trouble testing parachutes.
 
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One thing I would like to point out that occurred to me.

There is an assumption made in the video, and in other places, that the amount of UV light used for Retrobrighting will have insignificant effects on the plastic in comparison to the amount of UV that a plastic part has in the course of it's life up to that point.

Isn't it possible that, as the plastic item ages, and chemical bonds are disrupted, the effects of UV exposure will become more significant? In other words, once the deterioration begins, could UV exposure have an increasingly detrimental effect?

I'm not saying I have research to back this up, but I wouldn't feel comfortable making an assumption to the contrary without checking it out first.

Also like to say that I have never been a fan of painting plastics, because of two things.

1) It can ruin the texture of the plastic 2) it can peel off

Of course, many consumer products are painted plastic, and they look great. The main different is the skill and care taken in the prep work. This creates a very high barrier for entry to painting vintage plastic items. The painter must be very skilled and spend a significant amount of time and care on the prep.

Retrobrighting is orders of magnitude easier because you are just dipping something in liquid and leaving it for awhile. Because of this, it's going to persist, and it will be important for the longevity of these vintage items (in general) to continue working on the science behind it.
 
vol.2 said:
Also like to say that I have never been a fan of painting plastics, because of two things.

1) It can ruin the texture of the plastic 2) it can peel off
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That is true, but I think what has happened in the past, when folks have tried it, is that they have used an inappropriate paint. Neither of these two problems happen with the Dupli-Color spray. In fact it is excellent at allowing the underlying texture to be preserved and its reaction with the surface allows bonding to the surface preventing peeling.

The only way to be convinced is to buy some and try it for yourself. It even adheres well to brightly polished or shiny ABS surfaces.

Have a look at the attached photo. The story behind this is that over the years for my tube equipment restorations, amplifiers,TV's etc, I have largely abandoned electrolytic capacitors in favor of film ones. Some of the better film capacitors are motor types or pulse grade types (the one on the left in the photo) this started out with a shiny blue plastic body. To make it look vintage I sprayed it with silver dupli-color paint. It micro-etched the plastic surface in the minutes before drying, a super good bond and doesn't peel off.
 

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I would trust you, Hugo, to paint any of my vintage plastic stuff. However, you are uncommonly skilled at these things, and there is an art to painting an item with a rattle can without getting runs, orange peel and fish eyes. Fewer than "not everyone" will be able to get a good result.
 
vol.2 said:
I would trust you, Hugo, to paint any of my vintage plastic stuff. However, you are uncommonly skilled at these things, and there is an art to painting an item with a rattle can without getting runs, orange peel and fish eyes. Fewer than "not everyone" will be able to get a good result.
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Second that. My spray paint work doesn’t come out great…
 
I just found a really interesting photo. Recently I restored a 1966 Australian made vintage car radio (big job as all the metalwork was rusted and required re-plating). One interesting feature that the clear plastic dial was yellowed, the plastic brittle and it was broken. So it got replaced with a reproduction dial.

But the interesting thing is, that relates to this topic, that where the plastic was shaded from sunlight, by the upper and lower edges of the metal escutcheon, the plastic is still clear and pristine looking (see photos).

Another interesting thing, it is not surface yellowing, the plastic has yellowed through its full thickness, where exposed to light.

This is elegant proof of the destructive effects of sunlight, on plastic, and the yellowing effect it appears to have on it. Because in this case the plastic was perfectly clear originally, its easy to see the yellowing. So coating the plastic, and shading it from light with paint, is almost certain to have a protective effect on it, slowing down the degradation.

(Apply spray paint well merely requires some practice, preferably on some unimportant surfaces)
 

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I think that's common with a lot of plastics. I noted that my eyeglasses with polycarbonate lenses eventually take on a yellowish tint; it's faint, but visible. My current pair uses real glass--resists scratching and stays clear.
 
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