I seem to remember that there is some product that is designed(?) to restore old yellowed computer plastic to it's original "whiter" appearance. Can anyone tell me the product's name?
I know that anything containing bleach might help, but I'm wondering about a possibly better solution?
Once you try retrogaming, you'll never go back...
It's called retrobright. It's more trouble than it's worth IMHO.
Next time I want to de-yellow a case I'm going to investigate painting it. I've also wondered what sort of results a gentle bead blast would get.
EDIT: Also, I've read recently that people are finding that the retrobright process doesn't provide lasting effects. One guy had gotten good results but after 3 years or so, the yellowing was back. And that was on cases which had been wrapped and put away, not sitting on a desk in the sun.
Sorry to be such a negative nelly!
Life? Don't talk to me about life.
http://retr0bright.wikispaces.com/
Here's some interesting background info on why plastic changes color: http://www.vintagecomputing.com/index.php/archives/189
Retrobright results look great but its not exactly available at your local supermarket.
most likely you will have to build your own chemical concoction following a retrobright recipe on the net.
there is risk and some horror stories around.
I haven't attempted it and its not on the todo list yet.
Badmofo why do all your cases look like you purchased them new yesterday?
This topic reminds me that a few years ago, I found a Sinclair ZX-80 which was in great shape -- except for yellowing on its case. I had a cannister of Bon Ami (powder-type cleanser containing crystallized bleach), so I gently scrubbed it into "like new" appearance (Bon Ami's motto is "Hasn't Scratched Yet"...referring to it's non-abrasive properties).
The ZX-80 has retained its restored "white" skin, even though I've had it on display in a curio case for years.
I ran out of Bon Ami a long time ago -- and local stores no longer carry it. That's the reason I was inquiring about alternatives like RetroBright.
Thanks for the input, everyone.
Once you try retrogaming, you'll never go back...
wrote:Badmofo why do all your cases look like you purchased them new yesterday?
That's just years of collecting and filtering out the nasty ones 😀 Most of mine come from the local tip, so it's just persistence, luck, and managing to outwit the staff there who fortunately are not the sharpest tools in the shed.
Life? Don't talk to me about life.
wrote:It's called retrobright. It's more trouble than it's worth IMHO. […]
It's called retrobright. It's more trouble than it's worth IMHO.
Next time I want to de-yellow a case I'm going to investigate painting it. I've also wondered what sort of results a gentle bead blast would get.
EDIT: Also, I've read recently that people are finding that the retrobright process doesn't provide lasting effects. One guy had gotten good results but after 3 years or so, the yellowing was back. And that was on cases which had been wrapped and put away, not sitting on a desk in the sun.
Sorry to be such a negative nelly!
The effect will always eventually come back, oxygen will inevitably find a way to re-bind to the bromine in the plastic.
What I've seen suggested is, after retro-brighting, applying a thin coat of a clear low-sheen varnish.
The thing that makes retrobright great is that it doesn't harm decals or logos. Painting will cover them up, and bead-blasting will strip them off. Painting will give your plastics a permanent colour, but the bead blasting just reveals a new layer of plastic to go through the yellowing process.
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Retrobright results look great but its not exactly available at your local supermarket.
The official recipe isn't, but IMO there are all sorts of problems with the original recipe anyway. All you really need is some sodium percarbonate (i.e., 'oxygen bleach'... OxiClean or whatever your local equivalent brand) and water. Just mix it fairly strong... about twice the strongest ratio listed on the box, submerge the plastic parts in the mixture, and leave it in the sun for a few hours.
It takes longer to work, but it's cheaper, safer to handle, and it seems to give better results. Everything I've seen that's been treated with the paste mixture has come out with a mottled/blotchy whitening, whereas the milder liquid mixture doesn't tend to do that.
wrote:...OxiClean... and water. Just mix it fairly strong... about twice the strongest ratio listed on the box, submerge the plastic parts in the mixture, and leave it in the sun for a few hours.
While I haven't tried any brightening processes yet, I am curious to try this. When you say "leave it in the sun for a few hours", are you refering to leaving the submerged plastics in the vessel in the sun, or to remove the submerged plastics from the vessel and set the plastics in the sun, which I assume will dry out the oxiclean. For either case, what rinsing step is needed, if any?
Plan your life wisely, you'll be dead before you know it.
Leaving computer plastics in the sun is the WORST thing you can do. It is the sun that discolors them in the first place because the sunlight interacts with the brominated flame retardants in the plastic causing them to turn that disgusting yellow-brown that looks like tobacco stains.
When you say "leave it in the sun for a few hours", are you refering to leaving the submerged plastics in the vessel in the sun, or to remove the submerged plastics from the vessel and set the plastics in the sun, which I assume will dry out the oxiclean. For either case, what rinsing step is needed, if any?
You leave the plastic parts submerged, and put the whole container out in the sun. For best results use a clear-ish container so that light can disperse more evenly throughout.
Leaving computer plastics in the sun is the WORST thing you can do.
Sunlight, or more specifically UV light, is simply a catalyst that destabilizes the bromine compounds in the surface of the plastic. Generally that is a bad thing, because it causes the bromine compounds to oxidize and turn yellow. But it can also be used to your advantage if you want to reverse the process... if you expose it to UV while it's submerged in a hydrogen peroxide solution, the bromine compounds will turn loose the oxygen atom and bond with hydrogen atoms instead, which gets rid of the yellow color.
wrote:Sunlight, or more specifically UV light, is simply a catalyst that destabilizes the bromine compounds in the surface of the plastic. Generally that is a bad thing, because it causes the bromine compounds to oxidize and turn yellow. But it can also be used to your advantage if you want to reverse the process... if you expose it to UV while it's submerged in a hydrogen peroxide solution, the bromine compounds will turn loose the oxygen atom and bond with hydrogen atoms instead, which gets rid of the yellow color.
