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MG TD TF 1500 - Removing chrome plating ideas

I suppose I'll never learn. I should have told the plater to tape off certain threads or have done it myself, but now find I need to remove some plating from some threaded studs. Muratic acid? Any ideas? I don't have a die for the threads or I'd just run a die over them. Thanks for any ideas.
ZBMan

Are the studs mounted in chrome? Not sure why you need to remove the chrome, but can't you just put the nut on a few times?
E.B. Wesson

I did a google on this and the two processed that seem to be real are:
1 part HCL (Muriatic Acid) and 3 parts water. Let the part soak

(Always add the stronger to the weeker)

and

a Lye (NaOH)solution and electic current to unplate the part, use a Stainless cathode.

Most often the comments are bring it back to the plater.


Now Chrome and the underlying nickle for tenatious oxides so the HCL/H2O may not work.

What size is the thread?

Jim B.
JA Benjamin

It would seem that finding the correct die and mechanically removing only the offending area might be easier than mixing up an acid.
JE Carroll

Brian - I am with JE, you can get a die (or even a couple) from British Tools and Fasteners a lot easier than fussing with the acid baths. E-mail me at SUfuelpums@donobi.net - I have another idea. Cheers - Dave
David DuBois

Coming back to Edīs question - do you really need to remove it ? I would expect it to go by itself after a few uses of the threads
Mike
Mike Fritsch

Can't screw the nut on because the plating makes the stud too big, hence the removal.
Chrome is quite hard, and will kill a die quickly. If the die overrides the chrome and then jams, it will immediately chip the cutting edge, making it junk.

JAB has the answer, as given in my most authoritative industry standard book.
HCl at 10-50 volume % and room temp will do it; higher concentration or temp. will make it faster but more likely to damage the part - don't let it sit too long.
(note that commercial muriatic acid is already diluted; the concentration should be on the label.)
Or reverse plating AKA electro stripping, in alkaline bath. Lye or washing soda or even baking soda, about 6 oz/gal.; 5-6V, around 0.2A per sq in. In other words, a small 6V battery charger will do. Cathode can be copper, steel, SS or other - not Al. Commercial stripping cathodes are generally copper.
Plating chemistry and other parameters is very critical, but stripping is quite forgiving.

FRM
FR Millmore

Thank you all. I believe I'll try the reverse plating first as suggested by both J A Benjamin and F R Millmore and see how that turns out. I've tried electro rust removal before and feel confident I can set it up to work correctly. I'll report back later.

Brian Warmuth
ZBMan

This thread was discussed between 21/01/2012 and 27/01/2012

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