Retr0bright Support Thread

[Harrison]

Re: Retr0brite Support Thread

That's great. Sometimes the other side can surprise you. I had a very long discussion with a big Atari ST fan on the CA forums over the past months and it was all very logical, civilised and didn't result in a flame war. Very surprising when the discussion was the old ST vs Amiga one. He was however a fan and long time user of both platforms so had a more objective view on everything and even admitted that his views were based on his personal experience in the US of using STs more than Amigas for DTP and music creation. Two things that the ST was initially better for.

Anyway, back on topic. I thought it would be great to also include a Q&A section within the CA Wiki once we have everything to put into it. I've already begun constructing the page in the Wiki ready. And I think have a question and answer section that answers some of the most commonly asked things about the process would be good.

[Merlin]

Re: Retr0brite Support Thread

@ Zetr0 / rkauer

Get this!! Our Retr0brite process has been validated by another very experienced chemist (harpo) over at Atari Age!!

This is what he wrote:
----------------------------------------------------------------------------------------------------------
OK,
I will chime in here. Professionally, I have BS and MS degrees in chemistry and worked with polymers (plastics and such) for many years. I have not tried this protocol on my own cases that are yellowed yet, because I am just getting back into my old system while teaching my son some computer programming skills (what a great system for teaching programming ).
IMHO, the chemistry that is presented is valid for the mechanism of the "ageing/yellowing" phenomenon and how to reverse it.
When using the materials described be aware that if you don't follow the protocol TO THE LETTER you are out on your own and working with some potent chemical materials and can not be certain of the results you will obtain. I will reiterate what others have said, concentrated hydrogen peroxide is an EXTREMELY powerful oxidizing agent and can cause burns to the skin (I know from first hand experience), explosions when mixed with reducing agents (think rocket fuel), or damage to other materials it comes in contact with.
The 2% hydrogen peroxide you get at the pharmacy is not concentrated enough to accomplish this reaction. You need to use concentrations in the 12-15% range. You can start with the peroxide available at a beauty supply for bleaching hair but be careful to dilute it properly. If you do not know how to calculate the dilution ask for help! And "if a little is good, more must be better" DOES NOT apply here. The purpose of the TAED from the Oxy is to act as a catalyst. A catalyst is an agent in a chemical reaction that reduces the energy required to get the reaction going. You want the catalyst to be "pushing" the reaction, not excess concentration of the peroxide. That is the beauty of the protocol developed. If you use the concentrations and the materials described you should get undetectable amounts of oxidation of the base polymer and only reaction with the bromine compounds. The other thing to remember is that the UV is VERY important. The UV breaks the weak bonds in the peroxide causing the formation of the active radicals. If you have an old "Black Light" pull it out and use it. Otherwise wait until you have a nice sunny day. And as soon as the yellowing is observed to be gone, remove the piece and rinse it thoroughly to get rid of all traces of the TAED and OXY.
My feeling is that those individuals who have observed degradation and roughening of the surface of their plastic cases probably used too high a concentration of peroxide. If you stay on the dilute side and use the catalyst and UV so that only reaction with the bromine is favored, you should get an outstanding result.
As far as slowing the recurrence of the yellowing, I would suggest using a very light coating of ArmorAll or other surface protectant. It will slow the absorption of oxygen onto the surface and also reduce the amount of UV penetration slightly. It will have that slippery overly shiny feel and appearance that all surface protectants leave, but it will work to slow the recurrence of this phenomenon if that is foremost to you.
----------------------------------------------------------------------------------------------------------

That's all I need to prove that we have got it absolutely right in the way we are going about it. I am absolutely made up, as I was looking for someone impartial to validate my chemistry reasoning all along.

Result!!!!

[TheCorfiot]

Re: Retr0brite Support Thread

@Merlin

A very proud day indeed my good friend, Well Done.....

TC

[Merlin]

Re: Retr0brite Support Thread

@ TC

You don't know how much that post means mate; the trolling and cries of "Heresy!!" that I have had to endure from 'non-believers' has been something else, harpo's post makes up for all that and should be enough to silence the critics. The fact that it came from "the dark side" of the Atari camp is a bonus and goes towards helping to pull the communities together.

To have someone with far more experience than I have about plastics saying in print that we are spot on with our process is praise indeed. Zetr0, rkauer and I knew the science was sound in theory, but I was always in fear of someone more qualified than I coming up with a "Yes, but...." and completely trashing my reasoning.

Now I can get on with writing the articles up without fear of being contradicted. That's a BIG relief.

As I said on Atari Age, aren't all of the best inventions British?

Does this mean I am officially an Alchemist now, to go along with my name?

[Merlin]

Re: Retr0brite Support Thread

I've done some more research on this and it would appear that the specific PDBE we are dealing with is one called Tetra Bromo Bisphenol A (abbreviated to TBBP-A). TBBP-A is extremely photo sensitive to UV light and can under go selective debromination and further photolytic degradation, ending up as chemicals such as 2,4,6 tribromophenol and Bisphenol A. The half life of TBBP-A can be as low as 2 1/2 hours under UV light (which explains quite a bit when you look at our results). There is a possibility that these get extracted from the surface and end up in the liquid, although I'm not 100% sure about this.

I have a few abstracts and technical papers to trawl through over the next couple of days, after which I can be a bit more specific on the actual mechanism.

If you 'Google' UV photolysis of TBBP-A, there's quite a lot out there if you are having trouble sleeping.....

[G-H]

Re: Retr0brite Support Thread

Crikey TC, that's what "David Dickinson" looks like now?!?!?!?!
Nice job

[Merlin]

Re: Retr0brite Support Thread

Update...

We've finally managed to get the Wiki coughing and spluttering into life. Here's the link:-

http://retr0bright.wikispaces.com/

I'll be adding the science bits this weekend.....

[Merlin]

Re: Retr0brite Support Thread

OK,

I've now added some of the scientific explanation, without making it too heavy a read. Comments are welcomed.

[TheCorfiot]

Re: Retr0brite Support Thread

@Merlin

Excellent reading, I'm extremly proud and tip my hat off to you sir

Hip Hip

TC

[gazcbm]

Re: Retr0brite Support Thread

I hope to retry the experiment this week so fingers crossed.

BTW If you go to Argos you can get an electric handheld food mixer for £4.99, usefull to mix the gel with.

[gazcbm]

Re: Retr0brite Support Thread

Well it is official, I am giving up.

[Zetr0]

Re: Retr0brite Support Thread

Dont give up Gaz!!!

whats your setup my friend?

talk me through your apperatus

[gazcbm]

Re: Retr0brite Support Thread

Hi Zetr0,

I will take pictures of my setup and post it here ASAP.

Essentially my last experiment,

1 UV energy saving bulb from Maplins
500ml HyrdoPeroxide from Sallys 12%
1/4 Teaspoon vanish Oxi Action
2 tablespoons Xanthan Gum
1 teaspoon of glycerin.
mixed with food mixer

1 Commodore 128 case

The case has lost the slightest of yellow but from what I see its patchy.

However, this is the 4th time. I have tried some keys in liquid solution with Asdas own Oxy and again with Merlin's pure TAED but it did not make any change.

If it counts, I have done the experiment in the Garage (lighting conditions natural light during the day - dark at night) and in a room (lighting conditions dark) all with the uv bulb no more than 12 inches away.

People talk of foaming when adding the oxy, I am not seeing it at all.

The last experiment was 24 hours, previous to that I have tried 2 and 3 day trials.
Gaz

[Zetr0]

Re: Retr0brite Support Thread

@gazuk

whats the power of your UV bulb m8?

I would recomend atleast 60 watts buddy.

[Merlin]

Re: Retr0brite Support Thread

There's something not quite right here; I suspect that the case may have been lacquered before or maybe has been treated with something like AutoGlym or Armor-All. This could be protecting the surface too well....

Do you have a dishwasher, that you could maybe put the case through on a cool cycle?