ANy way to get safely remove the yellowed discoloring off white or off white hardware plastic housings?

I have never been able to seriously effect the yellowing but the best stuff I have found to clean the casings is FOAMCLENE or similar foaming cleaner from RS / Farnell etc

This question came up a few years back, and here's what I remember of the discussion.

The discoloration is caused by either airborne contaminants or the plastic oxidizing.  Not much can be done about either case.

Airborne contaminants such as cleaning solvents and cigarette smoke adsorb onto and absorb into the plastic.  The surface layer can be removed with detergent and water.  There's little that can be done about the stuff that has been absorbed.  It has chemically bonded to the polymer.

As they age, plastics lose the plasticizers and anti-oxidants added during manufacturing.  When this happens, they turn yellow.  Ultraviolet light from sunlight or fluorescent lighting aggravates the problem.  Nothing can be done; the problem started as soon as the product left the assembly line.

Using solvents to dissolve the yellowed layers results in a sticky mess.  Using abrasives such as sandpaper takes the finish off and scars the case.

When Digital shipped the first VT100s ca. 1980, the cases were eggshell white.  Four years later, they were anywhere from light yellow to light brown, depending on the environment.  We tried every solvent available to us, about 30 in all, and all we managed to do was melt holes in the test case.

My guess is that manufacturers don't worry what a system will look like in 5 years, because its expected lifetime with the original owner is only 3 years.

@ JohnnyCanuck:

Hello. Thank you for your reply! YES! AN ANSWER!!!! I know there is no limit to mankind!!!

Now, can this be purchased as a semi-complete product since I see some of the chenicals that make up the cleaning process cannot be combined if I read that online article correctly. I see the receipes, but what about a branded product... ...too soon yet to market it?  

Please reply.

Thank you!

   

As I mentioned earlier, you cannot buy it, you have to make it yourself.  The important thing is to get hydrogen peroxide in a strong enough solution - 6% to 12%.   One source of this might be a hair salon (for bleaching hair).

Here's a video.

http://www.youtube.com/watch?v=ysj2PlMPohE

@ JohnnyCanuck:

Thanks for your reply! Yah, I got so excited about reading it, I forgot you told me it wasn't for sale. I see you can make it a few slightly different ways, but everyone is using a strong hyrdrogen peroxide and Oxi-Clean-like cleaner plus another substance. Thanks for the YouTube.com website links.

Please reply if you wish.

THANK YOU!!!  

I would paint it black or white or any other color, so the plastic gets a new coating that won't have the same aging/discoloration problem :)

@ JohnnyCanuck:

Your thoughts if you use 3% hydrogen peroxide instead??? I know it is much cheaper. I am wondering if it is effective at all? The video link to YouTube.com you linked me with states that the guy who is making the solution says he tried the 3% and worked, but not as effected as he wished, but nonetheless it did work to a degree! He must have had to perform many treatments before getting to something better he had when using the 3%? Where it is noted that the 12% hydrogen peroxide took fewer times to reverse the yellowing process. I figure a slower whitening process would prove more control I could maintain over the whiting process. Your thoughts?

Should I also tackle my *light gray* (or even a different color besides white) plastic parts to the hardware's casing and remove the coloration as well or not???

I have very *mild* yellowing, but not as bad as the person's Nintendo hardware in the video link. I have yellowing, but not as bad yellowing as in the video. I know he states the item is more yellowed that the video shows as the guy in the video makes note. I am just wondering if the 3% will have some positive effect or none at all? I would think if you kept the corn starch amount down and/or increased the hydrogen peroxide & the oxygen cleaner with more UV light would also have a more positive effect using a 3% solution of hydrogen peroxide?

Please, please reply.

Thank you!!!  

Please reply!!!      

@ JohnnyCanuck & Anyone here:

I need help!!!

I see I need a UV light source for this little project for it to work. Now I have questions about UV light. Will *ANY* blacklight (or spelled: black light) work for this to happen or not? I'm talking about the deep purple bulb that you can buy (and that is getting tougher in my area to find). It is strange because I see the blacklight florescent tubes are mostly white in color, but the bulbs are deep purple… ….hmmm???  
I am new to experiencing UV light and blacklights.
 
Let me clarify my question:

ARE ALL BLACKLIGHTS UV LIGHTS AND GIVE OFF THE UV LIGHT (I DON'T WANT TO SAY "RADIATION" (or maybe I should?) THAT IS REQUIRED FOR THE REACTION TO TAKE PLACE??????

...or are *SOME* blacklights NOT UV lights (do not give off UV radiation) since UV light is considered dangerous since they are used for home for example, at kids’ parties (the glowing posters) use and safety. Therefore the exposure radiation is removed??????

...I"m confused is it the UV radiation or the UV light (or isn't it one in the samething???) from a blacklight that I need for the reverse chemical reaction to occur???

I was talking to an associate at Home Depot that is supposedly an electrician and we couldn’t figure this issue out. There was one florescent tube that STATED that is gave off UV light (or radiation?). The tube appeared white for the most part. There was a blacklight bulb (one of those newer lower energy bulb designs) that was deep purple that had NO STATED information regarding that it gave off UV light. We both thought it was for safe party use and did NOT give off UV light (or radiation?). It shows kids partying on the product package. We did agree that the blacklight florescent tube was indeed a UV light (or radiation?) because it stated it. The blacklight bulb was much cheaper than florescent blacklight tube. I would have to go out and buy a blacklight tube lighting fixture or lamp in order to use the florescent blacklight tube where I have a lamp that I can simply screw the blacklight bulb into.
What’s your thoughts? What is right?        

Please reply. I NEED YOUR HELP HERE. This is all new to me.

Yes, I figure I am going ahead and try the 3% first and see what happens as I said in my last post FIRST. I have nothing to lose, just 62 cents if nothing happens. I think I *could* get some response.  

Please answer my concerns, PLEASE!!!!

Thank you!!!

Been a long time since I played with blacklights.   ; )

There are different kinds of UV lamps, but most consumer bulbs are UV-A
So most any bulb you can get at a "Home Depot" should be OK.

http://www.ehow.com/facts_5004820_types-uv-lamps.html

http://www.ehow.com/uv-lamps/


These 3 are from American Air and Water, which mostly deal with germicidal lamps, but has some interesting info sprinkled here and there


http://www.americanairandwater.com/uv-facts/uv-types.htm

http://www.americanairandwater.com/lamps.htm

http://www.americanairandwater.com/uv-facts/uv-germicidal.htm

@ coral47:

Hello. Thank you for your response. So basically if I get that pretty deep purple blacklight bulb (even it is listed as UV-A),  even if it does NOT state that it gives off UV light (or radiation) on the packaging, it will work for me and this experiment as you have read thus far?

Please reply.

Thank you!

It should.
I still have one of the old fashion 12" florescent straight bulbs that is that "pretty deep purple", and it is UV for sure.

@ coral47 & all:

Thank you! So, Give me a couple of days and I will let you know what happened after I do this litle experiment to let you know my experience on this issue. I will leave this thread open a bit longer.

Thank you for your help so far.
 

This will also work on grey plastic.  In the youtube video he is treating an original nintendo which is grey.  The UV light does not have to be a black light.  You can put the coated parts in the sun and it will work.  Also look at this page and check out the pitfalls that may happen.  Apparently using hydrogen peroxide above a 10% strength can cause a "bloom" effect on the plastic, so I would keep it to 6% or below.  If you use 3% it may take several treatments.

Sorry, forgot the link.

http://retr0bright.wikispaces.com/Problems+and+Pitfalls

@ JohnnyCanuck:

Thanks for the reply and the added information. I am about to conduct this process. That added information is definitely an added guide from past experiences. Thank you! This just reinforces my belief to use a LOWER concentration of hydrogen peroxide for the FIRST test. It is better to take little steps than giant leaps. ...and I also did not realize that the SUN plays MORE of a pivotal role with this chemical reaction than expected. ...it is SUGGESTED to REALLY USE the blacklight instead for better control (the sun with all that nuclear fission and fusion -- a powerful power source). ..and TIME to sun exposure does matter too. I will be watching this experiment very carefully and short periods at first. I will use the sun, but have it out for very short periods. When I say "it", I mean PARTS AND PIECES of the whole hardware and not the entire unit.  

Like I said, I will be back soon.

Thanks so much so far!
     

Oh, let me add... ...that "LOWER concentration" is the 3% hydrogen peroxide to use FIRST.

Will be back...

Hello. I have a few questions before I finally reply back at the conclusion of the this solution:

My Questions:
1.      Can the plastic become discolored or become yellow AGAIN now after this chemical reaction reversed the process back to its near original condition over time? If the answer is ‘yes’, then how long can it take to color – a faster or slower rate this time to yellow again or discolor than the first time? Would this same solution here work again a second time just as effectively?

2.      Can the use a clear coat protectant UV (non-yellowing) covering (like an aerosol spray can) on the treated plastic prevent the UV from discoloring back again in the future? It is proven the bromine (the chemical in the plastic that is a fire retardant) reacts with UV light and creates that yellowing/discoloration effect in the plastic. Can this be somehow blocked with some clear coat protectant on the surface of the treated plastic?             

Please reply.

Thank you!!!

hmmmm... I haven't seen any definite mention to those questions, but based on my experience (though limited in this specific area), I will say:

1.a.   yes it will.

1. b.    unknown, but probably similar to the original.
environmental conditions would also effect the speed.

1. c.   it should.

2.   possibly. I would think sealing it from air would help a lot.
I would test on a piece that is non-critical or hidden, just to be sure that there is no bad interaction between the plastic and sealer.

Hello. I am back.

Well, the solution worked!!! YES!!! I basically followed the recipe from the Youtube.com video. Reason: Well defined and explained and uses a thickening agent that is cheaper than other recommendations.
 
Video name:
 Removing yellow color from old white plastic - Retr0bright PART 1 & 2

Websites:
http://www.youtube.com/watch?v=ysj2PlMPohE
http://www.youtube.com/watch?v=_vnJfbtTWUQ&NR=1

However, I modified the recipe for this mixture second and subsequent tries in the video links above after realizing I need to modify the recipe for efficiency and effectiveness.

The recipe per alecjahn in the video is:

½ pint (8 oz.)  12 % hydrogen peroxide as an oxidizing agent
(I used 3% hydrogen peroxide (H2o2). Reasons: 1. Many times cheaper to begin to test with. 2. Very popular to find in local stores. 3. I wanted to use a lower concentration of H2o2 to test first to see what kind of reactions and end result would occur since alecjahn did attempt using the 3% H2o2  4. It appeared to me that there were some positive results. 5. My yellowing discoloration was less severe than alecjahn, so a lower concentration may just work fine for my hardware yellowing. If it proved effective, I would keep using this, even if it required more treatments or attempts. I figured I would rather take small gradual steps and giant leaps and I could overdue it.)          
 2 heaping spoonfuls Corn starch as a thickening agent
(This is much cheaper and easier to find than xanthium gum or arrowroot as recommended thickening agents.)  
1 tsp. of Oxygen cleaner as the active catalyst
(Alecjahn uses “Sun Oxygen Cleaner”. He does mention “OxiClean” and it was more money. I never heard of Sun Oxygen Cleaner, but I have heard of OxiClean. OxiClean a slightly more in cost, so I figured you get what you pay for at the time of purchasing OxiClean. I have now learned there is no difference in effectiveness. I guess OxiClean has all the praise. Website:  http://www.associatedcontent.com/article/1675682/sun_oxygen_cleaner_vs_oxiclean.html?cat=6 . So next time I would get the Sun Oxygen Cleaner to save some money.)

Did the first treatment in outdoors in the sun where the sun was bright in a clear sky, but not that hot of a day. Temperature was approximately 60 degrees F.  I mixed the first two ingredients well, heated the mixture in a microwavable bowl for 1 minute, and then only added the oxygen cleaner when I was ready to apply directly to the discolored plastic.
   
The first treatment after being outdoors, I learned this during the process:
1.      I would reduce the total amount of the first two ingredients since I found his quantity made just too much after realizing I had a considerable amount left after the first treatment. What a waste. You can only coat the plastic just so much before it gets really thick and messy. Now, I would increase the oxygen cleaner quantity since I wanted the reaction to last longer since it is the catalyst. Now you say, ‘Why decrease the amount of hydrogen peroxide since they need to react with each other?’ Believe me, ¼ pint ‘is enough’ to react. I just found the amount of oxygen cleaner relatively little to the amount of hydrogen peroxide available in the bowl.    
2.      In the outdoors, the mixture dries too fast. In about 10-15 minutes, the mixture was dry and becoming flakey. Basically, if dried, the chemical reaction is completely stopped. What a waste I said. I figured I would try it indoors instead to see if the drying time was slower. Now, I would need a black light for UV light/radiation to simulate the sun’s UV light in a separate room away from people.  
3.      The thickening agent using the corn starch is too thick. When you add more corn starch to the mixture, a percentage of the active ingredients in the mixture are often suspended in the thick mixture and not reactive at the plastic surface. Lesser amounts results in thinner amounts of the mixture where the active ingredients can react on the plastic surface better. So I would use less the next time.  
I then washed the treated plastic with warm water since I found warm water washes faster and more complete than cooler water. I inspected the treated plastic and found the discoloration was significantly less, however still remnants still remained.  
 
Now, I changed it to this following the first treatment:
1/4 pint (4 oz.)  3 % hydrogen peroxide.  
 1 level spoonfuls Corn starch as a thickening agent
3 tsp. of Oxygen cleaner

Now, I waited until night or when it got dark, this is when I would start the second and subsequent trials since now I would be using a black light. The UV light needs to be direct with no visible light (No daylight available or normal white lights lit in the area of the black light is directed to. ) so a dark room (absence of light) is necessary. I performed the same methodical process as the first treatment but different amounts of each ingredient in terms of creating the mixture.  Same results for the mixture. This time I placed the treated plastic immediately under the back light.    
   
More pleased. It seems there was increased removal of discoloration while indoor under a black light.

The second and following treatments after being indoors, I learned this during the process:
1.      The mixture remained wetter for a longer period of time. It dried slowly. Improvement over outdoors. This is very important since I did not have to redo the treatment trials constantly over and over again in short duration of time.
2.      I would leave the black light running all night in the dark to see if the longer UV time period would indeed do more cleaning. The sun gives more kinds of UV light (UV-A, UV-B, & UV-C) than the black light that gives predominantly benign UV-A; so more time may be naturally necessary.  
3.      After approximately 3- 4 hours when I found most of the plastic surfaces dried of all the plastic parts being treated, I would mix the two reactants (hydrogen peroxide and oxygen cleaner) together in a bowl (omitting the thickening agent) and then immediately apply it to the discolored plastic, and them immediately place the plastic under the black light again. I did this modified method because instead of washing off the dried mixture off the treated plastic, adding the two parts reactant mixture to the previously applied mixture re-wets the originally dried mixture. The chemical reaction begins again without anymore thickening agent interfering with the chemical reaction. It is possible that trace amounts of the two reactants may have not undergone the reaction successfully the first time, so reapplying the same two reactants again may complete the first unfinished chemical reactive process.  Again, I give this treatment process until daylight morning where I then turn off the black light.
4.      Following treatments are conducted at night/dark hours under the black light (obviously during night/dark hours). Try to place all treated plastic pieces/parts as directly in the UV light as possible.  
5.      I would wash with warm water the treated plastic each morning after daylight arrived to see the results and removed the chemical product created. Not removing by washing the dried residue off the treated plastic after two fairly complete chemical reactions would only impede the next night’s attempt to have a successful chemical reaction since the waste product produced on the treated plastic was abundant. I did see improvements with each treatment trial. I would consider 2 treatments per night/dark hours. The second instance of each night’s treatment without the thickening agent.            
6.      Never use water in the mixture since water would dilute the two reactants and the thickening agent and make for less chemical reaction to occur in volume and duration. It is difficult enough to use the two reactants to get positive results, especially diluting the 3% hydrogen peroxide any weaker.
         
Total attempts until satisfied: 8

This works! I recommend this process to others who have this issue. Patience and time are necessary for this solution from start to finish. Using a 3% hydrogen peroxide may take a total of 4-5 nights using the nighttime method I recommend.  It is nice to know that this discoloration and yellowing is a reversible chemical process. Now, if the discoloration or yellowing of the plastic is more severe than my mild discoloration or yellowing, then either a 6% or even 12% hydrogen peroxide will be needed.

Nicely done experiment, and well reported.  

I need to carve out some time and do this to my Atari 8-bit.

Thanks.    : )

@ coral47:

Thanks for your reply. :-) Thank you for your comment regarding my detailed and thorough response.

Word of advice I may of not emphasized in my report above:
As soon as you add the oxygen cleaner to the hydrogen peroxide mixture and MIX IT WELL, IMMEDIATELY add it to the parts or areas to be treated and BRUSH WELL, then IMMEDIATELY place it under the black light. Time here is VERY IMPROTANT! Also you NEED TIME under the black light to work -- ALL night.    

I am now in the process of spraying the plastic with that clear semi-gloss (satin) coat over the plastic neatly and carefully with at least 2-3 coats for good UV protection. I hope this stops the discoloration from reoccurring again! Then I will put my parts back together for my hardware and be done.

Good luck with your experiment with your Atari. Be very careful with labels if you do not want them faded or wiped off. I think it depends on the ink that is used or the way the label is stamped on the plastic. You may want to mask the labels if the labels cannot be removed, but the watery consistency of the mixture may peel the tape you use to mask it with.

Please comment if you wish.

Thank you!  

>> Be very careful with labels if you do not want them faded or wiped off.

Good point.

Later...    

Nice analysis!  We don't usually get this level of response from questioners.

@JohnnyCanuck:

I usually do not get this level of asisstance on the World Wide Web! ;-) I am glad to share my experiences with you.  

Well, I have UV protected ther treated plastic and I will wrap it up in the next few days and put my hardware back together.

So, I can now close this thread. Thank you for your answers! But there was really only one solution!

Again, I appreciate your responses.

Like I said, there is many answers; but there is only one solution!

Thank you JohnnyCanuck!