After zinc-plating...

[paskharen]

Hi!

After Zinc palting, my parts have a dull grey surface (i suppose this is normal), and i wonder if there is a more gentle way to remove the dull grey without having to use a steelbrush? The steelbrush makes small scratches that im not too happy about..
Also, when chromating zinc parts, should the dull grey be removed before dipping in the chromate or after?
I have a caswell manual, but i guess its an older copy, because it doesn't give information about this matter....

[gmtorchred]

You need to add the zinc brightner to your solution. You will not have to wire brush if you use it. Dull or bright before chromate is a personal choice. I like the bright look.

[paskharen]

Ok, thanks.

The fact is that i use caswells zinc brightener, the only difference is that i have my own plating solution (sulphate-based). The dull grey surface is more like a layer, and under it theres a nice bright layer of zinc.
Now... I wonder if someone can tell me if it would be better to remove this "layer", degrease in caswells degreaser, rinse and then dip in the chromate, or if the chromate still has the same qualities if i were to remove the "layer" after the dip?
Im thinking saltspray-resistans...
I am real novise when it comes to zinc-plating so please be patient with me (if im asking to many stupid questions..)
The chromate i use is caswells blue and yellow...

[woodjames]

I don't know all the specifics, but zinc can be bright dipped. I believe it's done with a VERY dilute nitric acid solution, something around 1/2-1%. You need to do the rest of the research to find the specifics. You could bright dip, rinse, then move on to chromating.
Jimmy

Ok, thanks.

The fact is that i use caswells zinc brightener, the only difference is that i have my own plating solution (sulphate-based). The dull grey surface is more like a layer, and under it theres a nice bright layer of zinc.
Now... I wonder if someone can tell me if it would be better to remove this "layer", degrease in caswells degreaser, rinse and then dip in the chromate, or if the chromate still has the same qualities if i were to remove the "layer" after the dip?
Im thinking saltspray-resistans...
I am real novise when it comes to zinc-plating so please be patient with me (if im asking to many stupid questions..)
The chromate i use is caswells blue and yellow...

[paskharen]

Thank you! This might be the answer i'm looking for since, the brightener doesn't seem to work so well in my home-made plating solution.
If anyone knows the correct mixing % for the nitric acid brightdip bath, please let me know.

Thanks again Jimmy!