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Removing Yellowing from Plastics - Part 4

I never have been a fan of the goop based recipes. I prefer just a plain old H2O2 and Oxiclean bath. I literally just use the 3% stuff in 1 liter bottles from Walmart. Now, before you say that's a waste of H2O2, I try and pack the bath pretty full of parts. I find that, with some occasional stirring and turning parts over to get optimum UV exposure, this method proves to be very safe and to produce very even results. Now, I haven't tried this with parts which are extremely yellow, since most of my collection is in pretty decent condition. But an average-yellow mouse took only 7 hours in weak MN autumn sun not very long ago.
 
Pavel_ said:
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..
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I've tried various types of masking tape - cheap stuff to real expensive stuff - it all comes off once that paste/solution is applied. Besides you'll have to wash the parts off real well afterward, and whatever you use to cover openings will probably come off during the wash off.
You gotta get it apart - that way you get to clean out the inside too :)
 
arfink said:
I never have been a fan of the goop based recipes. I prefer just a plain old H2O2 and Oxiclean bath. I literally just use the 3% stuff in 1 liter bottles from Walmart. Now, before you say that's a waste of H2O2, I try and pack the bath pretty full of parts.
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Then you mustn't have tried doing something the size of a Televideo 925 monitor case yet. You'd need gallons and gallons and gallons of liquid.
I agree though that for small parts like a mouse or keyboard key caps, the liquid is the way to go. It just gets prohibitivly expensive trying to process large pieces in liquid.
 
Yeah. My solution- get a big garbage bag and blow it up with air and stuff it inside of the shell so you don't need as much liquid. Works pretty good.

EDIT: If I actually had a Televideo 925, the cost would be worth it. :) Actually, I tend to use the plain 3% stuff from Walmart, and one time I even added a few liters of plain water to help the solution cover the parts. Still worked just fine.
 
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tezza said:
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
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Sweet so yes to these ones http://www.hardwareandtools.com/invt/0307207 and no to ones like this http://www.bulborama.com/store/cart.php?m=product_detail&p=815. Good now I know which Bulb to buy.


Lorne said:
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.
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Good then they will fit in standard tube lights then. That should be good as I have a few extra Tube fixtures that I can use. And thanks for the warning on opening them, I will be sure to be extra careful.


Thanks a bunch for the answers guys
 
Is very short-wave UV (UVC) more desirable than the UVA that you get from the typical "black light"? The emission peak's around 254 nm and will also erase EPROMs. Lorne, you should know about these--they're used in HVAC air purification systems, particularly for hospitals.

If so, then this would be the cat's meow. Another alternative would be a mercury-vapor lamp designed for outdoor use. Some of the metal-halide "grow lamps" are also pretty strong in the UVB area and can be gotten in 400 and 1000 watt sizes.
 
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Chuck(G) said:
Is very short-wave UV (UVC) more desirable than the UVA that you get from the typical "black light"? The emission peak's around 254 nm and will also erase EPROMs. Lorne, you should know about these--they're used in HVAC air purification systems, particularly for hospitals.

If so, then this would be the cat's meow. Another alternative would be a mercury-vapor lamp designed for outdoor use. Some of the metal-halide "grow lamps" are also pretty strong in the UVB area and can be gotten in 400 and 1000 watt sizes.
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I'm aware of them - they're used in air handling units for UV sterilization.
I don't much like the "Warning" that comes with those bulbs.
This H202 stuff is already dangerous enough.
I'm not sure I'd want to add another avenue for "skin burn and eye inflammation" to the process.
We can do that just fine with the H202 mixture all by itself :)
 
All,
tonight i will start with my new retr0bright attempt.
An A500 case using the immersing method and 5 litres of 35% H202 also adding 5 litres of water.

I will use a fairly large container as the A500's case is not the smallest in the world...

Should i add the OXY laundry booster to this? i have not used this in my previous attempts and everything worked out great.. What do you think?? isn't the H202 + UV lamp good enough?


(Before and after pics will be taken)
 
Pavel_ said:
Should i add the OXY laundry booster to this? i have not used this in my previous attempts and everything worked out great.. What do you think?? isn't the H202 + UV lamp good enough?
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You should add the Oxy. That is the key ingredient (the TAED in the Oxy actually).
I think Merlin would agree that the H202 & UV shouldn't do anything by itself, other than get the parts wet.
If you've had good results without using the Oxy, I'm amazed.
Maybe the parts were simply getting cleaned in your previous attempts.
Add the Oxy this time, and you might be amazed.

Take those pics.
 
Okey, i just added the Oxy in the container. So far nothing is happening... the Oxy made the liquid less seethrough almost like.. cloudy.. but no bubbles or anything else (it's only been 10 min though).

I always had result with just H202 and UV. I have used it on A500 keys, A500 mouse, A1200 case.. perfekt result every time. However it does take up to about 4 days.. I hope with the Oxy it will take a lot less..
 
I'm new to this site. I'm getting back into the world of old computer collecting (I used to have a massive collection, but that's a long story). I started it up again with an acquisition of a Mac SE/30 off of Craigslist for a whole $10 (and yes, everything works!). Anyway, I stumbled across these threads because of a friend of mine and spent a day reading through every single post of all 4 parts. I want to extend a big thanks to everyone who has worked on this! I'm starting my de-yellowing process with the top of the mouse.

Here are the before pics: http://www.flickr.com/photos/mikerm19/sets/72157623032882679/

My first ever trial piece is "baking" right now. So far so good!

I love the forums, thumbs up

Edit: I just got home!! AWESOME!!!!! It worked beautifully! I updated the flickr set linked to include the results of my test. I'm sold. It's time for the rest of the Mac to get the treatment. Thumbs up to everyone who developed this method, If you ever find yourselves in Albuquerque, NM, dinner is on me.
 
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mikerm said:
Edit: I just got home!! AWESOME!!!!! It worked beautifully! I updated the flickr set linked to include the results of my test. I'm sold. It's time for the rest of the Mac to get the treatment. Thumbs up to everyone who developed this method, If you ever find yourselves in Albuquerque, NM, dinner is on me.
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Hi,

Glad it worked well for you!

Reading these recent posts make me think I should get into gear and process my remaining stuff. I have a colour genie (+ keys) and a couple of monitors that could do with "the treatment".

These final de-yellowing projects have been on the back burner for some time. Recently, I've found all the "spare" time I can devote to vintage computers has been spent troubleshooting hardware problems! Maintaining a working collection takes quite a bit of time.

Always interesting though, and always something to learn.

Tez
 
How do you guys deal with monitors or computers that have tubes built in? I know you can discharge a CRT, but I'm so in-confident I could do it correctly and not blow myself across a room or kill myself in the process.
 
I've only worked with a few monitors (or computers that have had screens built in), and none of the work was for de-yellowing purposes. I found I could easily remove the cases without discharging just by being careful and having the right tools e.g. long necked screwdrivers so your hand didn't need to go anywhere near the componentry as you undid the screws. However I can appreciate some might be difficult. In fact, I have got a couple of monitor cases that need de-yellowing and I can already see the screens might be tricky to remove.

Where there is a will there is a way though.

I've done some work on a Mac monitor on the past and I certainly made sure I discharged the screen before I did. It wasn't too difficult, and how to do it was easily found on the Net (it's been a while and I can't remember the details now). I'm not enough of a techie to know if this method could be used for other screens though.

Tez
 
I finally took my A500 case out of the bath. The result is pretty much shite.. It has not restored to it's original color and i think i know why - crappy UV light.

All my previous attempts have been successfull, the ingrediense were the same this time around except the UV source wich in my previous attempts was the sun.
 
lyonadmiral said:
How do you guys deal with monitors or computers that have tubes built in? I know you can discharge a CRT, but I'm so in-confident I could do it correctly and not blow myself across a room or kill myself in the process.
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And I'm the same as Tez.
I've done a few monitors, but I've never discharged one yet (I don't know how).
I'm just careful. I did get zapped by the anode a couple times while I was repairing one. It didn't hurt but it did wake me up a bit.
I figure if I don't touch the yoke, I won't get zapped.
When I have had to get close to the yoke, I've used a thick rubber glove on one hand, and put my other hand in my back pocket, and I'm still alive.
 
Pavel_ said:
crappy UV light.
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You're not alone - others have had crappy results with crappy UV lights too.
The fluorescent tube types that I use seem to work fine, although nothing beats the sun.
But if it's sun only, you won't be doing any deyellowing at night.

There should have been no harm done.
If you process it again, either in the sun or with a better UV light, it should come out fine.
 
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