Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Telephone Restoration Projects and Techniques => Discolored Plastic and Bakelite - Improving it Chemically => Topic started by: HarrySmith on February 18, 2011, 08:42:41 PM

Title: Another Peroxide Experiment.
Post by: HarrySmith on February 18, 2011, 08:42:41 PM
I am working on a very dirty SC 1543, it has a clear plastic number card cover that was very badly discolored. I decided to try a peroxide treatment. I went to Sally Beauty Supply and purchased Clairol Clairoxide 20. It is 20% peroxide hair dye. I decided not to go with the Retrobrite paste and went with just liquid. I added a pinch of Oxiclean and set it out in the South Florida sun for 4 hours. I also put the switch pileup cover in and a part of a badly discolored 500 I was sanding. The results are good! The dial cover and switch cover showed good improvement. The Blue 500 part came out great! I am going to try the clear plastic SC parts again tomorrow with longer sun exposure. Pictures below.
Title: Re: Another Peroxide Experiment.
Post by: Phonesrfun on February 18, 2011, 08:54:07 PM
I am going to try the clear plastic SC parts again tomorrow with longer sun exposure. Pictures below.

You guys in Florida, with the year-round sun!  Humph!

:)

Title: Re: Another Peroxide Experiment.
Post by: stopthemachine on February 18, 2011, 09:31:12 PM
Awesome--great results!  I'm actually about to try the magic peroxide recipe tonight.

I'm glad you tried it with a 1543 phone--I had just posted about results of peroxide with this series of phones.  I have a pink 1543 that looks salmon and a yellow 1543 that could use a little color work.  (The bakelite yellow handset looks fine though--just the case needs a "charge.")  Any suggestions with this series of phones or can I do the same treatment as the 500/1500/2500 series (the PVC plastics)?  I know too that certain colors don't work so well which is why I was especially wondering about yellow...because I also have some semi-funky yellow WE phones too.

The South Jersey area has been seeing the 50s the last few days, but nothing like Florida.   :)  In the summer, South Jersey will be perfect for giving the phones a peroxide bath, but until then, I'll get the lamp out. 
Title: Re: Another Peroxide Experiment.
Post by: HarrySmith on February 18, 2011, 09:42:01 PM
Yeah, gets kinda boring, always green, always sunny. Guess we all have our burdens to bear.
The reason I went with liquid is last time I tried the paste was on a Yellow 500 and ended up with spotty results. The bad results were due to uneven application of the paste. You can see the liquid worked great on the Blue 500 piece. I would not be afraid to use the liquid on any color.
Title: Re: Another Peroxide Experiment.
Post by: Brinybay on February 19, 2011, 04:15:33 AM
I am going to try the clear plastic SC parts again tomorrow with longer sun exposure. Pictures below.

You guys in Florida, with the year-round sun!  Humph!

:)


Yeah, I second that Harumph!  ;)
Title: Re: Another Peroxide Experiment.
Post by: AE_Collector on February 19, 2011, 11:42:11 AM
Yeah, I second that Harumph!  ;)

Seems to be us "Pacific Northwest" guys complaining here! Looks like a beautiful day today here in Vancouver. Going to go do a weather check in Washington too though. Point Roberts WA here I come.

Terry
Title: Re: Another Peroxide Experiment.
Post by: HarrySmith on February 19, 2011, 06:13:31 PM
OK, second treatment on the clear SC parts today, this time a full 8 hours in the South Florida sun. No further improvement in removing the yellowing. Still I am very happy with the results, it is a marked improvement over the original state and although still yellowed they are now at least useable. I am very excited about the results with the Blue 500 part, it looks perfect. At $5.00 for a pint I will be looking for a different supplier but I plan on using it again.
Title: Re: Another Peroxide Experiment.
Post by: AE_Collector on February 19, 2011, 07:23:46 PM
The light blue and light green or turquoise colors seem like touchy ones to use the peroxide treatment on. It is good to hear that you had good results with light blue Harry.

Terry
Title: Re: Another Peroxide Experiment.
Post by: stopthemachine on February 19, 2011, 07:37:35 PM
How does the treatment work on yellow phones?
Title: Re: Another Peroxide Experiment.
Post by: HarrySmith on February 19, 2011, 08:33:01 PM
Yeah, this time it was great! I think the secret is the liquid which gives an even application. Last time I used the paste formula and ended up with a blotchy color. I would use the liquid on any color.
Title: Re: Another Peroxide Experiment.
Post by: GG on February 19, 2011, 11:28:43 PM


For those of us who don't have direct access to sunlight due to geography, time of year, being in an apartment on the wrong side of the building, or being in a place where stuff left outside can get stolen:

The retrobright sites refer to "ultraviolet," but there are two types: long wave, also known as "blacklight" often used as a special lighting effect (makes "fluorescent" paint glow, etc); and short wave, which is known to cause eye damage and skin cancer from overexposure, and also makes plastics turn icky colors. 

Which one to use for un-fading plastics? 

I suspect they're referring to short wave (because with the peroxide, it might reverse the original chemical reaction that turned the plastic an icky color), but does anyone here know?   And if short wave, then where can I find the bulbs or fixtures for that?   

The whole point of Retrobright paste was to get an even mixture with the peroxide so you wouldn't have to soak large parts in a large vat of peroxide.  But the information I've found refers to a British laundry product as one of the ingredients: what's the US equivalent?

Also beware of this:  Peroxide, particularly the stronger stuff, when mixed with acetone, produces a highly unstable explosive.  I don't know if there are any other combinations with peroxide and other chemicals that will blow up; I have to believe the Retrobright formula won't.   But the main thing is:  If you purchase large quantities of strong peroxide, you may find yourself with a visit from the FBI or Homeland Security, who may think you're trying to make bombs.  So be prepared to show them your phone refurbishing process, and be friendly about it (who knows, you might get them interested in old phone equipment too:-).  BTW, this is why the regulations about liquids carried on airplanes: a bottle of this and a bottle of that, mixed hastily in the aircraft bathroom, equals a bomb.  In case anyone here has ever grouched about those rules, now you know why they exist.   And PLEASE DO NOT publish the detail about peroxide plus acetone in forums frequented by the general public: although the information isn't classified, it's not common knowledge and should not become common knowledge. 

Also, whenever using these chemicals in the home: exercise all the usual precautions such as using a well ventilated area, no smoking or other sources of flame or ignition anywhere near, wear rubber gloves, wash your hands when done, and so on. 
Title: Re: Another Peroxide Experiment.
Post by: Bill on February 20, 2011, 09:53:58 AM
I think it is short-wave UV that gives you a tan and causes sunburn. Not to mention skin cancer if you get too much of it. You might try a tanning bed - perhaps a local tanning salon would let you put your phone in their machine when they have no customers.

Bill
Title: Re: Another Peroxide Experiment.
Post by: Dan on February 20, 2011, 12:29:43 PM
Great results on the light blue. Make sure the mix is the consistency of tapioca pudding. Don't microwave it too long or it will thicken too much.
Title: Re: Another Peroxide Experiment.
Post by: stopthemachine on February 20, 2011, 01:07:33 PM
I think it is short-wave UV that gives you a tan and causes sunburn. Not to mention skin cancer if you get too much of it. You might try a tanning bed - perhaps a local tanning salon would let you put your phone in their machine when they have no customers.

Bill
Haha.  That is a really funny idea!  Can you imagine showing up to Hollywood Tans, after-hours, (or during regular business hours for that matter) with a cart full of phones?  It would be like something from a sitcom--I could see Alan Young doing something like that for Mr. Ed: Ed wants a tan and now Wilbur has to explain to the workers that his horse wants a tan.  Sorry for my digression, but I just had to say it.   :D 
Title: Re: Another Peroxide Experiment.
Post by: cloyd on May 11, 2015, 02:06:23 PM
I have been reading this string with interest; I have a tenite ivory WE302 to de-yellow.  I am a little confused.  I was assuming that you put the treated phone in the sun for the heat.  So, you are putting an OPAQUE peroxide paste on the phone and the UV rays from the sun speeds up the whitening?  Perhaps it is the science teacher in me but has anyone tested this claim?  Does the shady side get less whitening than the sunny side?  If I am patient, can I get the same results indoors?  If so, how long?  Just wondering.  Thank you for the clarifications.
Tina Loyd
Title: Re: Another Peroxide Experiment.
Post by: unbeldi on May 11, 2015, 04:49:59 PM
I have been reading this string with interest; I have a tenite ivory WE302 to de-yellow.  I am a little confused.  I was assuming that you put the treated phone in the sun for the heat.  So, you are putting an OPAQUE peroxide paste on the phone and the UV rays from the sun speeds up the whitening?  Perhaps it is the science teacher in me but has anyone tested this claim?  Does the shady side get less whitening than the sunny side?  If I am patient, can I get the same results indoors?  If so, how long?  Just wondering.  Thank you for the clarifications.
Tina Loyd

Hi Tina,
It may indeed seem paradoxical as far as the transparency issue is concerned, but the more near-ultraviolet light is present the better these treatments do appear to work. I think high-energy light sets free more agents in the mixture for the reaction and perhaps helps overcoming the energy barrier of reaction (Arrhenius law).  The same can be achieved with strong UV-rich indoor lamps, and this is in fact usually the recommended setup.

For the ivory Tenite housings, I actually prefer using simple Clorox bleach which is much cheaper and available everywhere.  I cover up all ink stampings (date, H1 mounting code) with petroleum jelly to protect them and simply set the whole housing into a container with a mixture of ca. 30% to 50% Clorox and warm/hot water.  Then just let it sit outside in the sun for a half day or more. This works very well on the ivory plastic. Since the solution is clear, it is easy to check the progress.

[PS: also cover up the brass inserts for the base mounting screws, as brass is readily oxidized by the bleach. ]

Here is a phone that I bleached this way:
Title: Re: Another Peroxide Experiment.
Post by: Brinybay on May 11, 2015, 06:07:41 PM
The retrobright treatments I did involved an ordinary incandescent bulb.
Title: Re: Another Peroxide Experiment.
Post by: WEBellSystemChristian on May 11, 2015, 07:39:11 PM
I have no idea why, but UV rays really speed up the peroxide process. Use peroxide by itself and it defades very, very slowly. Use UV by itself, and it uses the reverse effect on the plastic!

It has nothing to do with heat, just UV exposure.
Title: Re: Another Peroxide Experiment.
Post by: TelePlay on May 11, 2015, 09:40:01 PM
I have no idea why, but UV rays really speed up the peroxide process. Use peroxide by itself and it defades very, very slowly. Use UV by itself, and it uses the reverse effect on the plastic!

It has nothing to do with heat, just UV exposure.

Okay, I'll take a whack at a simple explanation of the process.

Quite right on the "just UV exposure" statement.

Normally, two Hydrogen Peroxide (H2O2 molecules break down slowly, or more rapidly with a catalyst, into one molecule of water (H2O) and one Oxygen (O2) molecule. When using a catalyst, such as potassium iodide, the break down into water is quite rapid and the gas bubbling off is pure oxygen, which is dangerous in quantity. This is the normal decomposition reaction:

     2 H2O2 --->  2 H2O + O2



UV light does something much different to Hydrogen Peroxide. It splits one hydrogen peroxide molecule (H2O2) onto 2 free hydroxyl radicals   (2 OH-)

     H2O2 ---> +UV Light --->  2 OH-

The hydroxyl radicals are very strong oxidizers which in the presence of ABS plastic interact with the pi bonding to reverse the damage done to those bonds over time, damage which causes the plastic to absorb more light, to appear darker. The complex pi high orbital bonds are responsible for both absorbing and reflecting light. The free radical hydroxyl ions must restore the original plastic molecules surface bonds to what they were originally and the result appears to be a "bleaching" of the plastic, lightening it in color by reflecting more of the full spectrum light making it look lighter.

So, without UV light, you don't get the strong oxidizing free radicals, and you don't get the desired affect.



Okay, you organic or physical chemists out there, start with this and correct any of it if I got anything, or everything, wrong (the new memory card has not yet arrived and it's been a long time since this was fresh in my mind).
Title: Re: Another Peroxide Experiment.
Post by: Brinybay on May 12, 2015, 12:27:58 AM

Okay, I'll take a whack at a simple explanation of the process.
...
So, without UV light, you don't get the strong oxidizing free radicals, and you don't get the desired affect.


Maybe that's why it took 4 or 5 treatments to get mine white.
Title: Re: Another Peroxide Experiment.
Post by: TelePlay on May 12, 2015, 07:59:29 AM
Maybe that's why it took 4 or 5 treatments to get mine white.

Should have attached this table to the prior post. It shows the relative strength of several oxidizing agents. The hydroxy radical (OH-) is the strongest of those listed with atomic oxygen (O2) being right below it followed by ozone (O3), hydrogen peroxide and chlorine (the weakest).

So, without the UV light, hydrogen peroxide will have an affect but a lot slower.

Some people add Oxyclean to their peroxide mixture of choice. Oxyclean is 50-60% Sodium Percarbonate

Sodium percarbonate has 3 peroxide molecules in its formulation and in crystalline (dry) form is stable. When water is added to it, it breaks down to release the 3 hydrogen peroxide molecules and leave 2 sodium carbonate (soda ash) molecules in the solution.

     2 Na2CO3.3 H2O2 ---> 2 Na2CO3 + 3 H2O2

So, adding Oxyclean to a hydrogen peroxide solution (which contains water) releases even more hydrogen peroxide, increases the concentration of hydrogen peroxide, which in the presence of UV light will oxidize the plastic, do the job faster than just the hydrogen peroxide solution alone.

Interesting, isn't it.
Title: Re: Another Peroxide Experiment.
Post by: unbeldi on May 12, 2015, 09:03:59 AM
onto 2 free hydroxyl radicals   (2 OH-)

     H2O2 ---> +UV Light --->  2 OH-

The hydroxyl is neutral, not an ION!  You cannot create two negative entities from a neutral one, no matter how much UV is used. Photons cannot be converted to electrons yet.

Quote
The hydroxyl radicals are very strong oxidizers which in the presence of ABS plastic interact with the pi bonding to reverse the damage done to those bonds over time, damage which causes the plastic to absorb more light, to appear darker. The complex pi high orbital bonds are responsible for both absorbing and reflecting light. The free radical hydroxyl ions must restore the original plastic molecules surface bonds to what they were originally and the result appears to be a "bleaching" of the plastic, lightening it in color by reflecting more of the full spectrum light making it look lighter.

So, without UV light, you don't get the strong oxidizing free radicals, and you don't get the desired affect.


The lifetime of a free hydroxyl radical is only on the order of picoseconds, perhaps nanoseconds. Lisa's paradox questioned how this agent could possibly be effective on the plastic surface when removed from it in the thick paste where it was likely created, because the light might not penetrate that far.

While true that aging of plastic has damaged the surface by oxidation, your story does not explain how even more oxidation by hydroxyl radicals, or any oxidizer, would all of a sudden repair the damage. Usually oxidation doesn't repair anything, but causes harm.

The discoloration of plastics is due to the fillers used in them to tune their properties. Especially responsible are the flame retardants added to prevent the plastic from burning and providing more fuel for existing fires. Many of these contain bromides which deteriorate and release elemental bromine. Bromine is very intensely colored, so even extremely small amounts discolor plastics yellowish and brownish.  The bleaching processes oxidize the bromine, or other discoloration, and make it colorless once again, thus restoring the original color of the plastic.  But basically, the oxidation is always a process of destruction of pigments, and one has to be very careful to not be so aggressive that the desired pigments of the colored plastic are destroyed too, causing fading. This can easily happen with the pastel colors, such as pink and aqua blue. This can only be reversed by sanding the damaged areas, as the penetration is not deep.

The destructive power of the bleaching process also appears in the fact that the plastics after bleaching appear rather dull, the gloss is greatly reduced and must be restored by polishing.