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Removing Yellowing from Plastics - Part 4

I have a Beige unit and the keys are more gray than those that you've given the 3 day bath to in post #59.
I'm wondering if they had 'soaked' maybe too long. Perhaps 1 or 2 days would have left them a bit grayer and saved some of the fading of the letters on the keys.
Just thinking out loud here :)
 
Yeah, three days might have been overkill but I had to keep mixing the jar because the keys float when they get oxygen caught under them. The keys would have ended up looking drastically different had I not mixed it.

Still, I am satisfied. I'll try something without lettering on it next.
 
Guar Gum experiment - not a great success

Guar Gum experiment - not a great success

Well here in New Zealand Guar Gum is 1/2 the price of Xanthan Gum so I thought I'd give it a try. Note that the environment I used the Guar Gum in is exactly the same as I use with Xanthan with good results (inside a garage, UV bulb). I use a 35% H2O2 diluted to 17.5% (50/50) with a little Oxy laundry booster.

My results are as follows:

1. The mixture seems to thicken after settling a lot more than the Xanthan mixture. I find it a lot harder to get just the right consistency.
2. The mixture is similar in appearance to the Xanthan mixture.
3. After painting the mixture on the parts (in this case an Amiga 500 top lid) I noticed after a few hours that the bubbling was happening on the mixture that had run into the container and not on the parts themselves. Bubbling on the plastic pieces was minimal and the mixture seemed to be drying out a lot faster.
4. Left overnight (around 10 hours) under a UV bulb and pulled the parts. The 500 lid had suffered a LOT of bleaching as to basically call it a scrap part now. Some areas had dried, some not but the blooming was all over.
5. Tried the same mixture again on another 'test' part with the same results.

So...in essence..I'm keeping away from Guar Gum for the time being. I have had consistent good results with Xanthan so will continue using it. Only problem I had with the Xanthan was using the mixture out in our ozone depleted sunlight..dried way too fast and caused blooming again.

Hope this information is useful as I saw reference to using Guar Gum on the Retr0bright II Wiki
 
Hi DM,

Good to see another kiwi posting on here.

Thanks for putting this up. The more info on what DIDN'T work that gets out there the better

Tez
 
Black Plastic (again)

Black Plastic (again)

You might add this to the Wiki too.

I processed another piece with some black plastic parts. The black plastic was glued on, so I didn't want to try to remove it for fear of breaking it.
I used the same old paste mixture I've been using.
Something definitely happens to the black plastic.
What was once a shiny black, was now a dull grey.
The solution to the problem in this case, was a "magic eraser" (very fine abrasive).
With a little elbow grease and one of the erasers, I managed to get though what must have been the faded black layer of plastic, and got to some nice new black plastic. (I imagine any fine plastic or glass polish would also do the same trick - the eraser was just at hand).
I used the eraser on all but the top row of black, so that I could see the results.

Here's what it looks like now (I just have to do the top portion, and it'll look as good as new):

Back plastic.JPG
 
I did an entire Apple IIc not too long ago using a bath instead of paste. I just did the regular 3% H2O2 (Walmart has a special) and a scoop of oxi-clean and left it in the sun for about 8 hours. Worked like a charm. This was on an overcast, 50 degrees Fahrenheit day in Minnesota, but that didn't seem to affect it badly. I also ran out of the H2O2 before covering the parts, and so I just added water to finish covering the parts. I didn't need to add too much, and it worked out OK. I also agitated the mixture whenever it stopped bubbling.

One other thing I did with the IIc- it has some plastic parts with metal embedded in them. Specifically, the area near the handle and the drive slot cover. I was able to remove the spring-pins near the handle, but for the drive slot cover I squirted hot glue over the exposed metal. It remained protected from the mixture and didn't corrode.
 
arfink said:
I did an entire Apple IIc not too long ago using a bath instead of paste. I just did the regular 3% H2O2 (Walmart has a special) and a scoop of oxi-clean and left it in the sun for about 8 hours. Worked like a charm. This was on an overcast, 50 degrees Fahrenheit day in Minnesota, but that didn't seem to affect it badly. I also ran out of the H2O2 before covering the parts, and so I just added water to finish covering the parts. I didn't need to add too much, and it worked out OK. I also agitated the mixture whenever it stopped bubbling.

One other thing I did with the IIc- it has some plastic parts with metal embedded in them. Specifically, the area near the handle and the drive slot cover. I was able to remove the spring-pins near the handle, but for the drive slot cover I squirted hot glue over the exposed metal. It remained protected from the mixture and didn't corrode.
Click to expand...

Do you have before/after pictures of your //c?
I was thinking of doing this to mine at some point in the future.
 
Apparently Kilroy-71 can convert english to swedish quite well.
I wish I could do the reverse.
Nice photos :)

I hope I don't start calling Xanthan Gum, Xanthan Gummi !
 
I tried substituting a liquid Oxy product I picked up at the supermarket, thinking the TAED would be already dissolved in the solution.
Forget about that idea.
It didn't work worth a damn.
The parts smelled real nice as they were processing, though.
 
UV light

UV light

Sorry in advanced for the stupid question, but could anyone point me toward the "right" UV lamp? (IE one that works and provide a link to buy one if possible) and where one could be bought? I assume UV lamps are Different from Black lights right? (if they aren't different then I'm set as I have a couple black lights already.)
 
How should one use retr0bright on a monitor? should the monitor always be disassembled before putting on the mixture? The thing is i'm trying to restore a Commodore 1084S monitor but that thing looks like it can't be taken apart.. i have no idea where to begin.. and it's sooo yellow..
 
Mac collector said:
Sorry in advanced for the stupid question, but could anyone point me toward the "right" UV lamp? (IE one that works and provide a link to buy one if possible) and where one could be bought? I assume UV lamps are Different from Black lights right? (if they aren't different then I'm set as I have a couple black lights already.)
Click to expand...

Not sure where one can be bought where you are but DO go for the flourescent tube-type UV lights (some are small and coiled and fit a standard light socket..these are ok). DON't go for the round bulb-types..the ones that are the same shape as a normal lightbulb. Unless otherwise specificed these are probably just standard lightbulbs painted with a purple paint that only lets out UV light and filters the visible light. The UV that escapes is minimal.

Tez
 
Pavel_ said:
How should one use retr0bright on a monitor? should the monitor always be disassembled before putting on the mixture? The thing is i'm trying to restore a Commodore 1084S monitor but that thing looks like it can't be taken apart.. i have no idea where to begin.. and it's sooo yellow..
Click to expand...

Definitely disassemble it if you can. The retrobright mixture painted on things that are NOT "yellowed" white or light-coloured plastic (like black trim, knobs, labels etc.) can have variable effects.

Tez
 
Mac collector said:
Sorry in advanced for the stupid question, but could anyone point me toward the "right" UV lamp? (IE one that works and provide a link to buy one if possible) and where one could be bought? I assume UV lamps are Different from Black lights right? (if they aren't different then I'm set as I have a couple black lights already.)
Click to expand...


I got mine at Home Depot. They're an about 18" long tube type fixture. (I think they're also called blacklights).
Just be careful how you open the packaging on those things. They can be very hazardous.
 
Pavel_ said:
How should one use retr0bright on a monitor? should the monitor always be disassembled before putting on the mixture? The thing is i'm trying to restore a Commodore 1084S monitor but that thing looks like it can't be taken apart.. i have no idea where to begin.. and it's sooo yellow..
Click to expand...

That's about as good as one of my first posts on the subject back in Part 1, when I was asking if you had to disassemble a keyboard before you treated it. You've taken the torch for the goofy question :) Thank you.
The answer as Tezza replied, is yes. You are only treating the plastic.
As with many things on vintage computers, you have to remember that they put them together, so they have to come apart. While it may not look like it after 30 years, they do come apart. Sometimes parts may be glued together, but I've found most times they're not.
 
hehe, i'm glad someone could take the "goofy question" torch off your hands :)
It's just that this monitor looks like a beast! There's no screws, no nothing.. I'm thinking that if i put something over the vents and the screen itself then maybe i don't have to take the whole thing apart..

btw tezza,
I have a new project ongoing and i'm using your recipe... pics are comming as soon as i get this damn monitor apart!
 
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