Recent searches
Search options
Administered by:
After watching several videos on #retrobrighting techniques, I started a couple of small-scale experiments to see if my setup works.
This year's Christmas decorations will shine in UV light! 
If you followed my A3000 restoration threads, you can easily guess which yellowed plastic I need to retrobright 
https://mstdn.io/@codewiz/113586277421694238
This cheap PC keyboard will go first to test the effectiveness of my #retrobrighting process.
The very first step consists in a bath in dish soap and hot water. This should prevent grease and other dirt from blocking the UV light and the ozone.
While I was at it, I also threw in the PCB, just to see if my soap is safe for electronics.
Then I rinsed everything with fresh water and wiped with 70% isopropyl, which didn't seem to disturb the key engravings.
Many #retrobrighting videos dip the plastic to be treated in concentrated hydrogen peroxide, or coat it with hair bleaching cream, which may contain other chemicals.
But 12% peroxide is kinda expensive, and I couldn't find any in nearby stores. The fastest delivery I could find wouldn't arrive in time for Santa to admire my first retrobrighted keyboard.
So I decided to try an alternative: sodium carbonate. Pure and natural since 1874... and dirt cheap at $0.10 per ounce!
I'm no chemist. Until yesterday, I didn't even realize that washing soda isn't the same of baking soda (sodium *BI*carbonate).
But I suspect what was actually needed was sodium *PER*carbonate! 
https://en.wikipedia.org/wiki/Sodium_percarbonate
Wikipedia confirms that, in water, percarbonate decomposes into hydrogen peroxide. Which is why it works the same for #retrobrighting.
But I don't have any percarbonate at home, and it won't arrive before Dec 29 either.
Moreover, how much would I need to get the equivalent of 12% peroxide? Now I regret not paying enough attention in #chemistry classes! 
Before realizing that sodium percarbonate was actually what I was supposed to use, I started a small AB-test in my UV chamber using plenty of sodium carbonate.
After spending about 12 hours dipped in the solution, the '+' key (treatment) is visibly less yellow than the '-' key (control).
Despite using the wrong #chemistry, my first #retrobrighting experiment didn't completely fail. Can anyone explain this surprising result?
I also bought a Sterilite storage box large enough for the A3000 keyboard. I believe it's made of polypropylene or polyethylene, which shouldn't block UV too much, but since my led strip is IP65, I figured I can just hang them on the inside of the lid.
While waiting for one gallon of 12% hydrogen peroxide from Home Depot, I started another #retrobrighting experiment with concentrated sodium carbonate solution, just on a larger scale than the minus key.
While the #chemistry is the same, the conditions are quite different:
- I had to weight the plastic to keep it from floating: will the covered areas look different?
- The same UV light source is being diffused in a much larger environment
- 5W of light won't keep this larger reactor warm, so I moved my electric room heater next to it
- This cheap box doesn't have a gasket all around the lid. Will it quickly vent out the radicals produced by peroxide decomposition in UV?
My second #retrobrighting experiment with sodium carbonate for 24h ended with a slightly paler PC keyboard.
The result is very uneven and the engravings look bleached. I'd call it a failure: don't bathe your vintage plastic in sodium carbonate!
The two controls on the left have been kept outside the box (backspace) and inside, but suspended above the liquid (equals/plus).
Meanwhile, the 12% peroxide arrived, and I poured the entire 1 gal bottle in my #retrobrighting reactor for another 24h session with that poor PC keyboard.
Notice the =/+ key sitting on top of a plastic weight to compare the effectiveness of the reaction in air.
While hydrogen peroxide (H2O2) is commonly used to disinfect wounds and even for oral rinsing, at 12% concentration it must be handled with gloves.
I touched the wet plastic with my bare fingers, and after a few seconds they were stinging, and the skin was already partially corroded. 
I guess that's why you can't purchase peroxide at higher concentrations from retail stores in the US.
The sacrificial PC keyboard turned shockingly pale after spending ~30h in my peroxide bath with UV light.
The +/= key, which was suspended above the liquid, is almost the same shade.
The minus and backspace keys are untreated, while the backslash key was only exposed to sunlight and then UV, but never went in with the peroxide.
Contrary to reports that #retrobrighting weakens plastic, as far as I can tell the material remained strong and normally flexible.
The finalized process appears to be safe enough to start treating our venerable #Amiga 3000 keyboard.
Apart from the space bar, the keycaps don't need #retrobrighting. A good wipe with Windex will do.
Before proceeding, I dipped the plastic shell in dishwasher soap and warm water for 15 minutes. This should remove any grease or dirt that might block our reaction.
As an extra precaution, I'll start off with the keyboard case suspended above the surface of the peroxide.
The +/= key has shown the effectiveness of the alternative dry process, which is also said to yield more even results.
I'm kinda concerned that my UV led strips might illuminate things unevenly, so I'll come check every few hours and rearrange the parts if necessary.
After 48h of dry #retrobrighting at room temperature, my #Amiga 3000 keyboard was still yellowish, though a paler shade than before.
The space bar has an uneven gradient of yellow, suggesting that this air-gapped process doesn't guarantee uniform results.
Oh no! My box is too narrow to dip both halves of the keyboard shell side by side, and the peroxide level is too low to cover them together.
I can't leave it like this if I want a uniform #retrobrighting result...
I exposed the reactor core once again to rearrange the parts.
Now the front part is face down, fully covered by peroxide but not lit by UV. Will it still get brighter this way?
The bottom part is still half covered, and will need to be flipped every few hours.
I could just add tap water to rise the level, but it would also dilute the solution, and I still want to #retrobright the #Amiga 3000
front panel and the mouse later.
Rising the level to cover the keyboard without diluting the peroxide wasn't hard after all. Thanks to @RegGuy for suggesting this. 
While I was at it, I also poured hot water into the jars to speedup the reaction a little.
It's time to prepare the #Amiga 3000 front panel and the shell of the "pregnant" mouse for #retrobrighting.
As before, soak the parts in warm water and dish soap for 15 minutes, then rinse in the shower.
Reloading the #retrobrighting reactor core for another 24h run.
The "control bars" keep the parts from floating around, but borosilicate glass absorbs UV, which might result in uneven results.
The #Amiga 3000 front panel came out after 48h in the #retrobrighting pool. The result is uniform and the shade matches the original shade.
As for the PC keyboard, the plastic didn't become brittle or get damaged in any visible way.
Sadly, the #Commodore logo on the front visibly faded 
Is there a way to prevent this?
@codewiz FYI, Oxyclean is Sodium percarbonate - you can probably get some at Target/Walmart/Home Depot/etc
@pixel I happen to have a big bottle of OxiClean, but sodium percarbonate isn't listed among the ingredients, only "sodium laureth sulfate", "sodium bicarbonate" and "sodium formate" 
@pixel Ah, there's also a powdered variant which contains only two ingredients: disodium carbonate and sodium percarbonate, though they don't specify the quantities:
https://www.amazon.com/OxiClean-Versatile-Stain-Remover-7-22/dp/B005GI8UOO
Before I thought all laundry detergents were more or less the same, now I know that even the same brand name can have totally different chemical compositions 
@codewiz yeah. I used the regular original powder for retrobrightibg my Apple IIc and it came out really good. I also used UV lights (it was winter and I didn’t think the Sun would be enough)
@pixel Which UV lights did you buy? I have no idea how to measure the luminosity and the exact wavelength of my UV leds. I just picked these because they were cheap and powered via USB.
@codewiz I bought two of these. I don’t remember why those but I do remember reading a bunch about what would work and got those. It did work well though! https://a.co/d/8IyZDLi
Brave browser
“To prepare 100 L of 12% hydrogen peroxide solution, you would need approximately 465.5 g of sodium percarbonate.
As for the water, you’ll need to dissolve the sodium percarbonate in it. A general rule of thumb is to use a 1:10 to 1:20 ratio of sodium percarbonate to water (w/w). Based on this, you could use:
465.5 g sodium percarbonate + 4,655 g to 9,310 g water (approximate)
Keep in mind that this calculation is an estimate, and the actual yield may vary…”
@El_Jefe Both ChatGPT and Copilot (aka Bing Chat?) claim that you need ~280g of percarbonate to make a single liter of 12% peroxide.
If only we could find an expert human to check their reasoning...
@codewiz I use sodium carbonate (washing soda) to help take oil stains out of my work clothes. I'm not surprised it would lighten the color of plastic, but I'll bet it's done a number on the structural integrity of it.
@codewiz UV light alone already works, that's why you can also just put it outside in the sun in the summer. You don't need any chemicals at all.
@codewiz It's half the cleaning product. Percarbinate adds hydrogen peroxide to the mix. So you got bleaching from the UV alone and cleaning from your chemical. The peroxide will add to the bleaching a little.
I think you lose points for not using the Ctrl key as the Control. 
@jamie The 8-bit guy made exactly the same joke a few years ago: for some reason, he couldn't use the Ctrl key as a control in his experiment comparing various #retrobrighting methods.
And I also couldn't, because both my Ctrl keys are visibly less yellowed than adjacent keys.
I've seen keyboards whose space bar is more yellowed than the rest, but that's the only key having no engraving so it's plausible that it went through a different process.
So, why Ctrl?? 
Maybe somebody lost control?
@codewiz Looks effective to me. What were your ingredients and recipe?
@nop Dipped the key in a highly concentrated solution of sodium carbonate in a sealed plastic box for food, wrapped with a strip of UV leds (5 watts), and further wrapped with a towel to keep the box slightly warm. Cook for 12 hours.
The plastic is slightly opaque, probably polypropylene or polyethylene. I don't know how to tell how well it transmits UV light at 390-400nm. I've read that common glass blocks UV more than most plastics.
@codewiz Thank you kindly!
@codewiz I think the other reason is it's used for making bombs.
And how many gallons of peroxide can I buy online before they raid my house, find this weird box glowing in purple light and go: "aha! take him away!", without letting me finish to explain retrobrighting and vintage computing?
@codewiz ...it's not really a kind of skin corrosion but rather oxygen generated "within the skin" (which also irritates the nerves). Usually the staining disappears after a couple of hours with no skin damage remaining (which would be the case for skin corrosion). Typically, warnings are found on e.g. textile bleaches with peroxide that they may produce white spots on the skin..
@codewiz Thanks for sharing. Can't wait to see the results.
@codewiz Put something into the solution that is neutral to raise the level. A few glasses filled with water until the solution covers both.
@RegGuy Good idea! I'll look for suitable items...
@codewiz Glad to see it worked for you. Using hot water was a good idea too. Cheers!
@codewiz Does that require having to get into the shower naked with the Amiga parts? 
@amca I kinda expected a Rick Roll, but this is almost worse 
@codewiz I wonder if a reflective coating on the inside of the container would help provide reflections for better coverage. Aluminum foil tape or cheap mirrors maybe.
@davet I wrapped the tank in aluminium foil, but the plastic walls will filter some of the UV.
I wasn't sure how aluminium foil would react with peroxide. Some metals will rapidly oxidize, releasing enough heat to melt some plastics: containers:
https://www.youtube.com/shorts/5i3guKmuBUI
@codewiz I didn't see if everyone else has already pointed this out, but you can also use sodium percarbonate for your laundry, once you have some
@dan I've already tested that sodium carbonate to rewash some yellowed kitchen and bathroom towels, but they still look the same.
Guess I'll ask for a refund