Early Dunlop master cylinders

[Desmo]

Hello,

I would like to rebuild the three Dunlop Master cylinders. They are the very early ones with the small, narrow Dunlop lettering. The outer surface seems to be painted with black lacquer. Were the exterior surfaces originally painted or surface treated ?
Thank you for your help.

John

[Heuer]

Castings were heated and plunged into oil to give a matt black rust proof finish.

[Mich7920]

Hi John,

You can used a chimical product to be used to give the color black/blue to a weapon.
I did this for mine and it's nearly the same "color" than the original.

Mich

[Desmo]

Hello David,

Thank you. That means. It will be diffucult to repeat this job?!

Hello Mich,

Can you name a manufacturer of this chemical liquid as an example and would the surface have to be derusted before treatment? Thank you.

John

[Mich7920]

John,
I bought in France what I used so I think it is not valid for you nevertheless I'll send you the link to the website where I bought the products earlier.
You can easily find these products at the gun restoration suppliers. Tanning is very commonly done on guns.
The part must be sandblasted (no more rust or paint) and degreased carefully.
It is usually liquid where you dip the part. No problem for the interior, the chemical reaction is very thin. After the treatment let the part soak in oil for 24 or 72 hours.
The advantage is also that it is totally reversible by a simple sandblasting.
Mich

[mtnjag]

Have you talked to a good rebuilder?
The two i work with here will either rebuild or Restore the part.
In Restoration they will plate the part with a coating that looks original but is more robust and resistant to corrosion. And is impervious to brake fluid.

[Mich7920]

If you want to stay authentique, I think that any kind of coating isn't the solution.
In absolute terms, it's just cosmetic. They can be very rusty on the outside and still work perfectly.
So you might as well get closer to the original aesthetic.
Mich