Passivation

[mekanik]

Had a little look into this and it seems that Citric Acid can be used instead of Nitric Acid(link) but you would still have to put a protective coat over that so it looks like the etch primer would be a better solution,Just had a check in the shed, the Manor Paints is the Chromate(yellow base) that i prefer but Chromadex do a none Chromate etch if you prefer that.I got this for refurbishment of Spilka H type window hardware as they are made from mild steel then passivated and clear coated but this deteriorated after about 10 years, just out of interest where are you located, i am near Ulverston.
Hope that helps.
Regards
Mike


https://www.amazon.co.uk/Citric-acid.../dp/B00GOT02C2

[Voicecoil]

Had a little look into this and it seems that Citric Acid can be used instead of Nitric Acid(link) but you would still have to put a protective coat over that so it looks like the etch primer would be a better solution,Just had a check in the shed, the Manor Paints is the Chromate(yellow base) that i prefer but Chromadex do a none Chromate etch if you prefer that.I got this for refurbishment of Spilka H type window hardware as they are made from mild steel then passivated and clear coated but this deteriorated after about 10 years, just out of interest where are you located, i am near Ulverston.
Hope that helps.
Regards
Mike
https://www.amazon.co.uk/Citric-acid.../dp/B00GOT02C2

Thanks for that Mike, but I really wanted a simple chemical passivation process (i.e. just dip it) rather than some kind of painting. BTW, I'm just over the hill from you in Broughton, nice to find someone else up this way - one often feels a bit out on a limb living up here!

[mekanik]

Don't know if it's still operational, but there used to be a metal finishers(Hemsworth) @ Salthouse Mills, but Bill passed a couple of year ago, his brother Bernie might have taken it over, try Yellow pages, they used to do Cadmium plating @ the time i remember, they might have a solution for you.
Regards
Mike

[Voicecoil]

Cheers Mike, I'll see if I can find them.

[mekanik]

Nearest i can find is Carlisle
http://www.sbmcoatings.com/

[Voicecoil]

Nearest i can find is Carlisle
http://www.sbmcoatings.com/

Ahhh, I know them, might give them a try, though the shipping/travelling expenses up there and back might make what was "a nice idea" a little pricey. And it looks like I may have found the appropriate stuff on ebay

[mekanik]

And it looks like I may have found the appropriate stuff on ebay [/QUOTE]
Can you link me to that please.
Regards
Mike