Could I retrobright a Copal 222?

[Johan de Jong]

I have a Copal 222 that has rather yellowed and so I'm considering to give it the peroxide treatment.
When I took it apart I noticed the black bezel is just a matt painted piece of the case and not a separable part.
Is it safe to retrobright this piece? I will of course not put the peroxide directly on the bezel, but it is hard to keep it completely free from the gel and inevitably it wil be subject to the fumes.

[flipoclock]

I would not risk getting any peroxide on the black paint, I fear it will damage it. If you use the (green?) expensive painters tape, you might be able to keep the peroxide from leaking in.

[Johan de Jong]

Thanks Robert! I have to consider whether it is worth the risk. In the meantime I have given it a good clean and maybe it is not that bad after all. I'll see what I will do

[Johan de Jong]

Finally decided to take the risk and just do it!

First had to take it completely apart, as in this clock the mechanism is integrated in the case.



Then I used a brush to carefully apply the peroxide gel only on the case, avoiding the black bezel. I put the case in a transparent plastic box with the black bezel facing upwards to make sure the gel will also not later on run down on the bezel. And I closed the box with a lid to not let the gel dry out.

Here is my setup with a UV light and a cardboard box lined on the inside with radiator foil to make the most of the UV light and illuminate the clock from every angle. I simply blocked the mechanical timer on the UV light so I could leave it on for as long as needed.



After a first session it was still a bit uneven, but after a second session I was satisfied with the result. The matte paint on the bezel is luckily water resistant, so I could just wash down the peroxide with lots of water when finished. I also whitened the power cord (kept the motor in a plastic bag) and this worked nicely too!

I'm quite happy with the result



BTW I considered to use the painters tape but did not dare to apply it on the black paint as I was worried it might damage the paint.

[grandpasquarepants]

This is incredible! Amazing work!