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Removing Yellowing from Plastics - Part 4

Lorne

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Jul 27, 2008
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Chandler, AZ, USA
Wow, I must have not been thinking, I just got a UV lightbulb from Home Depot for $5.

Hopefully, you've read parts 1, 2 & 3 by now.
Those parts contain the information that tells you which UV lights seem to work better than others, and I suspect a $ 5 bulb from Home Depot isn't going to cut it.
I'm glad you got that H2O2 real cheap - you're probably going to need to buy more, the way you're going about it.
After your kidding with us, now I'm actually getting a laugh out of this.
 

Tupin

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Jun 7, 2009
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Hey, I'm new at this, okay? :)

I appreciate all of the help, and I'm going to get this to work no matter what.
 

Merlin

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Apr 23, 2008
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Wow, I must have not been thinking, I just got a UV lightbulb from Home Depot for $5.

There's many a true word spoken in jest, so they say..... :crazy:

My guess is that you weren't a science major, were you? Your $5 black light may work; all you are going to lose is the current mix of peroxide.

Keep the bulb about 12 inches from the part, you don't want the heat getting transferred to the part or you will get distortion.

I was one told "Read everything, before doing anything."

It's good advice.... from the guy that wrote the Wiki, in case you hadn't noticed.....
 

Tupin

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Yeah, I've found that reading all of those threads and the wiki did help a lot, and I realized that the reason I didn't get a real result on the mouse was because it wasn't completely yellow, it just had some yellowish-brown stains that my failed mixtures managed to remove quite nicely.

Like I said, I won't give up on this, and since I have some severely yellowed equipment, I'll keep trying.
 

Merlin

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Apr 23, 2008
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Well, the looooooooong threads just go to show the amount of development work that has been put into this project, and this is just at VCF; there are similar threads at English Amiga Board, Atari Age, the forum-system.cfg site in France and many other sites all over the World.

As you have realised by now, there are subtle differences between batches of ABS and you have to tinker to a degree for each batch. The 10-12% H2O2 and a small amount of Oxy is the best starting place to begin your experiments. If you add other stuff to the mix, you are out on your own and the results can't be predicted.

One good hint is to put your case parts in a cool dishwasher cycle, if you have one. This will remove dirt and prepares the surface better for Retr0bright treatment.

Good Luck!
 

Merlin

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@ Tupin

here are some useful tips that I posted over at EAB; I think these may help you.

1. If you have a dishwasher, put the parts in on a cool cycle first. This will ensure that they are clean and the surface is better prepared.

2. Keep the H2O2 between 10 to 15%, this is the ideal mix that gets the quickets results without attacking the ABS polymer.

3. If you are making the gel version, cover the parts with cling film after applying the gel. This reduces or stops evaporation and the effect that Zetr0 warns about.

4. Check on the parts every couple of hours. I wouldn't go more than 2 hours without checking the parts.

5. Heat is bad. Keep the UV at least 12" away from the parts or you risk heating them up and causing distortion, particularly on long or thin parts.

6. Above all, have patience; these parts have taken at least 10 years to yellow; a few hours extra to remove it won't hurt. Rkauer is spot on with his comments.

7. Protect yourself; wear rubber gloves and safety glasses. These are dirt cheap from DIY shops and you don't get another pair of eyes. 10% H2O2 will sting like a mofo if it gets into cuts in the skin. If you get a splash on your skin, rinse it under the tap for 10 minutes to ensure it's removed.

8. Blu-Tak or plastercine is ideal for weighting keys down so that they don't float.

9. If you use a jar, DON'T screw the lid on tightly!! This process evolves gas (oxygen) and pressure will build up and possibly burst a jar or bottle. If you need to use a jar, pierce a hole in the lid to allow gas to escape.

10. Once the reaction has finished, the solution can be safely disposed of down the drain, as the H2O2 will ahve decomposed to water; TAED is biodegradable so there's no risk to the environment.

If you clear coat the parts with an acrylic lacquer once they are restored, they won't go yellow again, as oxygen cant get to the surface. What rkauer means is that the case may eventually start to discolour again, but this could take years. A good UV protective car polish like Turtle Wax, Armor-All or Autoglym could also be used to seal the surface.

The gel is only of benefit if you are treating large parts, such as a monitor, printer, etc. where a large bath of solution would be expensive. The gel is also handy if you don't have a large enough container for, say, an A1200 case.

The solution doesn't react with Blu-Tak or plastercine. Tonyyeb proved that very early on in our tests over at EAB.

Also, don't go mad with the quantity of Oxy; TAED isn't soluble above 1.5 grammes per litre and adding a lot of Oxy will create foaming. I would suggest 1/2 teaspoonful per 5 litres of liquid as a start. You can always add more, but if it's foaming all over the place, you can't take it out!!
 

nathan

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Aug 18, 2009
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71
Location
Missouri
Just a quick comment on the availability of H2O2...

My sister owns a salon and I asked her about her source. She is able to order me 1L of 12% for $5, no problem. The outfit she deals with delivers, and it should be here either tomorrow or the day after. I figure this should last me awhile considering I'm going the gel route and don't have all that much stuff to de-yellow.

She did mention that people have done bad things with higher-concentration H2O2 and so this sort of stuff is pretty hard for 'civilians' to get ahold of. That said, if you know anyone with a cosmetology license (i.e. hair stylist) -- and most of you probably do -- they may be willing to get it for you presuming that your purposes are peaceful.
 
Last edited:

Merlin

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Apr 23, 2008
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290
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Manchester, UK
Hi to all the Retr0brighters out there!

In keeping with the best spirits of product development, I think it's about time that we started work on Retr0bright Mk.2. There are probably quite a few ideas that we could add to the basic recipe, and this is where all of you come in.

I've started a discussion topic on the Retr0bright Wiki. Please feel free to add your ideas to this topic and we'll see what is possible - remember, we've already sort of proved the impossible with Retr0bright in the first place, so don't stifle your creativity.

Ultimately, we could end up with a whole range of open-source Retr0bright products.

Thinking caps on, people!!

;)
 

Lorne

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Jul 27, 2008
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Chandler, AZ, USA
Holy cow!
After a long gap of no de-yellowing, I'm getting started again with some more stuff.
With this being part 4, and me not being sure if my final good recipe was in either part 2 or 3, I've wasted enough time to de-yellow a piece, just looking for the recipe.
I've now found it, printed it, and from now on, it will sit right next to the gallon of H2O2.
I wish my memory was what it used to be.
Before photos have been taken - now to get to the de-yellowing of a very yellow Tevevideo 910, and some other stuff.
 

Lorne

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Jul 27, 2008
Messages
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Chandler, AZ, USA
Televideo 910

Televideo 910

This was my best result to date.

A Televideo 910, that was supposed to look like this, but didn't:

Televideo brochure -.jpg

The label removed from the back side of the terminal shows what I had to deal with. This amount of yellowing on the backside and top, indicates that this Telvideo probably spent it's life backed up to a window.

Label area -.jpg

This one took 5 batches of the paste/gel solution = 10 applications (washed off between every two applications). The solution was on the parts for about 2 1/2 hours at a time, after which I either reapplied it, or washed it off, and started again with another application. Total time of processing under UV light was approximately a day.

Here's the result:

TV910 - side -.jpg

TV910 - front -.jpg

This one was processed using, and needing patience (in short supply here - but apparently that's what works). I also used the Kelzan Xanthan Gum this time, and it was the first time I'd had the opportunity to use it. It makes a very nice paste/gel, easy to work with (spread around and still sticks to verticals), and I suspect it had something to do with the results.

I am really chuffed with the results on this one.
 

Tupin

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Jun 7, 2009
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St. Louis, MO
Okay, I'm trying this again. I got a blacklight UV bulb and am submerging a few deyellowed items in it, the change this time is the bulb. Last time the bulb I got gave off tons of visible light and practically no heat, but this is the opposite. This is a true UV light, the last one was just a light bulb colored purple, which is odd because it said it was a blacklight.
 

tezza

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Oct 1, 2007
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New Zealand
This was my best result to date.

A Televideo 910, that was supposed to look like this, but didn't:

View attachment 2164

The label removed from the back side of the terminal shows what I had to deal with. This amount of yellowing on the backside and top, indicates that this Telvideo probably spent it's life backed up to a window.

View attachment 2165

This one took 5 batches of the paste/gel solution = 10 applications (washed off between every two applications). The solution was on the parts for about 2 1/2 hours at a time, after which I either reapplied it, or washed it off, and started again with another application. Total time of processing under UV light was approximately a day.

Here's the result:

View attachment 2166

View attachment 2167

This one was processed using, and needing patience (in short supply here - but apparently that's what works). I also used the Kelzan Xanthan Gum this time, and it was the first time I'd had the opportunity to use it. It makes a very nice paste/gel, easy to work with (spread around and still sticks to verticals), and I suspect it had something to do with the results.

I am really chuffed with the results on this one.

Very nice Lorne,

A great result. I still have a few units to process, but they have been low down on the priority list of spare time activities for a while.

Tez
 

Tupin

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Joined
Jun 7, 2009
Messages
436
Location
St. Louis, MO
Finally, results!

A mismatched TI-99/4a had yellow keys. After a few days in a jar full of 10% peroxide and oxy and a UV light, here's the before and after, I left the space bar untreated to show the difference:

Before:

IMG_2576.jpg


After:

IMG_2605.jpg


Kinda splotchy, but I'm impressed with the results. Thanks, Retr0bright!
 

Tupin

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Joined
Jun 7, 2009
Messages
436
Location
St. Louis, MO
Sorry, had my camera on the wrong setting, here are the Before and After photos again:

Before 3 days of submerging the keys in Retr0bright:
IMG_2576.jpg


After 3 days:
IMG_2606.jpg


If you notice, there was slight fading on the keys, but I'll take that to get the keys this deyellowed. :)
 

tezza

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Oct 1, 2007
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New Zealand
If you notice, there was slight fading on the keys, but I'll take that to get the keys this deyellowed. :)

Yes, I found this my Atari 130XE. It is a trade off. For a COMPLETE deyellow, some key letter fading can take place.

Tez
 
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