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Black Rhodium plating


#1

Hi Hitesh,

I must stress that I was only talking about PEN plating. I haven’t
done any bath-plating in 40 years. Here is my reply to your remarks:

you said you dry pieces after ultra and befor 10% pickle, is
drying necessary and what is the impact of it on final result? 

I’m sorry I forgot to mention that I usually break up my workday, so
I work on my castings on day one until I get the pieces polished,
then I run them through ultra and dry them so they don’t get
waterspotted until I start plating the following morning. If you work
in one continous process, there would be no reason to dry them before
degreasing.

do you do cathodic cleaning in an alcaline cleaner after ultra ? 

No.

i presume that you must have done Black RH by bath plating
(dipping) too,have you noticed any difference between bath and pen
regarding colour? (because according to my observation in pen i am
getting jet black colour where as in bath the colour is much
lighter) 

Again I have no experience with Black RH -bath-plating… But my
results are precisely as yours: Jet-black. Sometimes it is difficult
to get the colour even, specially when I have a large surface to
plate. I attribute that to my neglect of keeping correct temperature,
or my work-supply of the rhodium liquid has become contaminated.

is genuine BLACK RH available out there,because generally
RUTHENIUM is used in place of RHODIUM ? 

Actually I don’t know, I’ve never heard about rhodium beiing
replaced by ruthenium.

On my bottle it says: Rhodium Elektrolyt. I remember having read from
their brochure or catalog how much rhodium they put in the bottle.
I’m sure it said “rhodium” and not “rhutenium”; I would have noticed
the difference.

My tap-water is chlorine free, and it gives me no problems at all.
That is one privilege when living in a small community To me, black
rhodium plating is a blessing. Before I bought my Rhodinette, I had
to oxydize my pieces to make them portionally black, but rhodium is a
harder and longer lasting coat, and the piece ends up with much nicer
appearence.

Yours
Jon H. Holm
3740 Svaneke
Bornholm, Denmark


#2

hello Jon,

thank you for replying.

just to share my experience with you about your problem:

Sometimes it is difficult to get the colour even, specially when
Ihave a large surface to plate. I attribute that to my neglect
ofkeeping correct temperature, or my work-supply of the
rhodium liquid has become contaminated. 

i dont think the unevenness in colour is due to incorrect
temprature,or contamination in the liquid. for large surfaces there
is no other alternative then Bath Plating,but since you dont do that
try this raw trick: you must be using FIBRE TIP for pen
plating,choose a tip with one side pointed and the other side thick.
now gentely press the thicker side till it broadens to the shape of
brush. after cleaning it thoroughly apply it to the pen with the
pointed side inside. take a large dose of liquid and try plating.
according to my experience you should get better result,but as i said
this is a raw solution,final solution is bath plating as current gets
distributed evenly in it.

regarding your idea about tap water instead of destilled due to
contamination (i.e.it becomes acidic or alkaline which ultimately
attacks the base metal inside through microporous holes in the
rhodium plated above hence less durabality). i liked it, but the tap
water(apart from chlorinated) generaly doesnot have a balanced PH
value(i.e. 7.0) which means it is either acidic (higher PH 7.0).so i
would rather prefer fresh destilled for final wash.

thanks,
Hitesh Satikuver
Tanvi Arts
Mumbai (India)