Experiments with Peroxide/Bleaching

[FABphones]

Having read various methods of Peroxide and 'home' bleaching, I thought I would carry out a few experiments, trying a few methods and adaptations out for myself.

Although I believe these processes do have a place in many restoration projects - and others have had some fabulous results - my view of bleaching is that at best the results can only ever be a close match to the original colour. A truly original colour can only be achieved by chemically sanding, thereby revealing the original colour which remains underneath the damaged surface. The processes below can only ever artificially recreate a colour match - or not, if the process goes wrong (and if I get it wrong, you know I'll mention it...).

Hidden, inside areas show the best examples of the original colour. This is the colour and shade to aim for.

The key issues I wanted to test out were:

*Does coloured ABS lighten as well and evenly as whites and ivories.

*What will the results look like 6 months and 12 months after the process.

*What results do these methods give on Urea Formaldehyde.

In each instance below, prior to any chemical application, the item was pre-washed thoroughly in dish wash liquid and warm water to make sure any dust and grime was removed, and if necessary, dried with paper kitchen towel.

UVB rays will not penetrate glass so no glass containers were used.

After removal from the fluid each piece was wiped over with paper kitchen towel until dry, then washed in lukewarm water and dish wash liquid.

As, over time, I continue trying out Peroxide and Bleaching experiments I will add each to this thread.

And finally, the usual safety warnings when using chemicals. Wear gloves, old clothes (bleach will remove the colour from them too and result in a break down of the fabric structure). Follow the safety precautions on the containers, the manufacturers will explain everything better than I can - I mention this as CRPF has members of all ages, take care folks, chemicals can be nasty.

[FABphones]

1)  Peroxide Bath -  Blue ABS

Mix:  5% 40 vol Peroxide cream
        95% lukewarm water

Method: A sanded blue GPO Trimphone body shell was placed into a zip seal bag containing the above mixture. The purpose of using a sanded part was for a later experiment in colour change/similarity to a none sanded part. Additional sanding needed to be performed in order to take it down to its true blue colour but for this experiment I let the Peroxide do the work to see how even a colour match could be achieved.

The bag was placed into a semi-opaque plastic tub. This was to keep the contents safely away from children and animals, and as these bags invariably leak (this one was no exception) the fluid is retained in the tub enabling the Peroxide bleaching process to continue.

Every 20 mins the fluid in the bag (which was a grubby grey in colour), was swished around. This was to prevent any hot spots developing and to keep any misc small particles of Peroxide cream from settling.

Total Time:  2 1/2 hours. Full sun.
Temperature: 21 deg.

My findings: The colour change at this 95/5% ratio lightened gently. The colour lifted to an even blue shade. The shade of blue after 2 1/2 hours was the colour I had hoped for, and 'as near as' it was originally.

Photos: 1) Before sanding. 2) After sanding, before treatment. 3) After treatment. 4) A quick polish. 5) Colour comparison side by side with an untreated blue Trimphone.

[HarrySmith]

Interesting. Did you polish it after the peroxide bath? The reason I ask is it appears to have some gloss to it in the final picture. The color came back nicely.

[FABphones]

Interesting. Did you polish it after the peroxide bath? The reason I ask is it appears to have some gloss to it in the final picture. The color came back nicely.

Thank you and well spotted, I used Novus 2 to give it a quick polish up. I took a photo but forgot to add it, I will do it now. 

[FABphones]

2)  Peroxide Cream Rub - Ivory Urea Formaldehyde

Mix:  40 vol Peroxide cream

Method: A yellowed (and crackle glazed) 232 body shell with a crack to corner was brushed over with the above solution then placed into a zip seal bag. The bag was sealed full of air so it formed a large bubble shape and prevented the bag from making contact with the contents, after 30 minutes the body shell was removed, an additional fresh application of Peroxide cream brushed on then replaced in the bag. This 30 minute interval reapplication was performed three times at the beginning of the process.

Total Time:  2 1/2 hours. Full sun.
Temperature: 21 deg.

My findings; The colour change was slow, but for my needs the colour lifted enough. Any lighter and it would have been lighter than the other pieces (handset etc) which it needs to match in with. In particular I wanted the inner area of the crack to colour match with its surroundings, ready for repair.
One or two dark patches remain on the body sides. These were not quite so visible when the whole surface was yellowed. They will need to be fine sanded away when the build continues.

Photos: 1) Before.  2) Close up view of corner crack.  3) Out in the midday sun.  4) Close up of corner crack after treatment.