Passivation

I feel that I'd like to passivate some of the internal parts of the machine as experience tells me that stuff will slowly corrode up here in the damp Lakeland climate (we're not too far from the sea either). I was going to use the Caswell yellow chromate stuff (a bit nasty, but OK if you know what you're doing and reduce any leftovers to Cr(III) before disposing), but they seem to have stopped selling it. There are meant to be some safer non-chromate alternatives, but I can't seem to find anyone selling any in less than majorly industrial quantities - anyone got any ideas please?

Oh, and I did like the yellow colour of the chromate :upset:

Don't know if this is what your after, but i think i got my supply of etch primer from manor paints, used to use international but Akzo Nobel took it over and don't think it's available anymore.
http://www.manorcoatingsystems.co.uk...brication-of-a
Regards
Mike

Frost still sell various plating kits - www.frost.co.uk
They're not normally the cheapest source, but their plating kits seem comparable with other sources.

Thanks for the suggestion of Frosts - I'd forgotten about them. Sadly although they do a very interesting electro-passivation kit it's only for zinc :-(

https://www.frost.co.uk/paints-coati...ng-module.html ?

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

Quote:

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Originally Posted by m_c

https://www.frost.co.uk/paints-coati...ng-module.html ?

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Aye that's the thing I found, but it seems to be for zinc plated items rather than for ali.

Quote:

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Originally Posted by 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

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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!

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

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

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

Quote:

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Originally Posted by mekanik

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

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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 :nevreness:

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

Here you go:

https://www.ebay.co.uk/itm/Aluminium...HBXPysBtCp9FLw

Why they still have it on the bay of fleas when they've taken it off their website I don't know! Just waiting for some refund monies and I'll try buying a pot.

A lot of blacking, phosphating, plating and passivation chemicals are available from Access Chemicals; think the name is right,
they are somewhere near Rugeley.
Industrial quantities are not huge but they will sell per kg/litre.