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Rhodium Electroplating queries


#1

I have some queries about rhodium plating:

  1. What wire (Stainless steel or other) should I use for handling
    jewelry for rhodium and gold electroplating? Should I connect an
    alligator clip to the negaive terminal wire to hold the handling
    wire OR should I attach the handling wire directly to the negative
    terminal copper wire.

  2. I had read somewhere that one could electroclean in a stainless
    steel beaker or jug. Would there be be any problem if the jewelry
    touched the steel beaker. I mean to stay postive and negative
    touching each other. If not, then Why???

  3. What is Nitro cellular lacquer?

  4. The NC Lacquer that i bought is transparent and will not show up
    distinctly while lacquering. How do I color it?

5 a ). How often do i change the distilled water used for rinsing.
b) i am initially rinsing in tap water after ultrasonic cleaning then
in distilled water. Doesn’t the distill water contaminate with tap
water thus destroying the characteristics of the distilled water.
Should i use distill water throughout the process, even after the
dilute sulphuric acid dip for.

  1. Rinsing in running water under a tap can take away with it
    prcious stone like diamonds along with it into the drain. Then how
    do i rinse under running water.

  2. Dont traces of sulphuric acid still enetr the rhodium bath even
    if i rinse it in water.

8.after taking out the jewelry item from the bath and drag out
/rinsing is it required to place it in hot water.

  1. I do not have a steam cleaner. How do i clean and dry the item in
    the final stage

#2

Not sure where you are, but a really good company in the Uk who could
probably help are Hava Shapiro. I’ve bought my electro
plating/forming equipment and micro hydrogen solder unit from them
and they are really heplpful You could always email them with your
questions at info@technicalsupermarket.com or
havashapiro@btconnect.com.If you are in the States, not sure if they
would be able to help re US only products, but it’s worth a try.

Barbara


#3

Hi Rahul,

  1. You can use Stainless Steel for a wire. Gold also works well.
    Copper is fine too, because after one use it gets plated. For
    convenience, yes, use alligator clips on your rectifiers lead wires
    because it makes it easy to manipulate the handling wire.

  2. You can electroclean in a stainless steel beaker. Try not to let
    the jewelry touch the beaker sides or it can short out the
    rectifier. Most models of rectifiers have a reset button in case this
    happens. If you use a Pyrex beaker and an anode, same thing applies:
    try not to let the jewelry item touch the anode.

3-4. I am familiar with nitrocellulose lacquer for finishing wood
furniture and musical instruments. I am not familiar with its use as
a masking lacquer for plating. Some rhodium solutions are used at
room temperature so a variety of different lacquers will work just
fine for masking. But some rhodiums and most electrocleaners are
heated. Check the lacquer instructions to see if it will or will not
dissolve when heated.

  1. Distilled water should be used as a dip immediately before
    rhodium plating. There is no need to use it all the way through the
    pre-plating processes. You’re right that there will be dragout of
    the tap water into the distilled water that will accumulate over
    time. Thus changing the water depends on how many items you plate at
    one time and per day and of course on the volume of your rinse
    beaker. There’s no hard and fast rule that I know of. But I’ve plated
    over 100 rings easily before changing the distilled water rinse. If
    you want to be extra safe you could have two distilled water rinses
    prior to rhodium plating.

An old platers trick when plating items with lots of tiny detail,
holes, settings or other places where liquid can become trapped is
to set up 3 tap water rinses of different temperatures, such as
cold-hot-cold or hot-cold-hot, prior to the distilled water rinse.
(This is what I recommend when someone tells me that they notice odd
discolorations that appears as spots soon after rhodium plating –
especially if they tell me the ring has a lot of tiny settings or
"nook and crannies". On the other hand if the plated ring displays
areas of cloudiness, that’s usually an indication that tap water was
used as a rinse prior to rhodium plating -or that the distilled
water rinse has too much tap water in it.)

  1. Always a good idea to check stones for looseness before plating.
    You can allow the water to run into a beaker and rinse your ring in
    the beaker. If you drop the ring or a stone falls out, it will be
    contained within the beaker.

  2. If you rinse thoroughly before rhodium plating, there should be
    no problem. If the ring is highly detailed or with many tiny
    settings, you might want to use the cold-hot-cold rinsing method
    described above to minimize carryover or dragout.

  3. I have not used any rhodium that required a hot water rinse after
    plating. It never hurts to check with the rhodium
    manufacturer/supplier for details on its use.

  4. Clean compressed air will work too.

I hope this has been helpful.

Best Regards,

Elaine Corwin
Technical Services
Gesswein Co. Inc.
www.gesswein.com


#4

Rahul,

call Rio Grande, they have a good guide on plating that comes with
their plating sets or can be bought seperately. this book should
answer most of your questions.

just one of their happy customers, Jerry


#5

My, my, Rahul, what a curious fellow!! I’ve been plating for many
years, but I’m not really an “expert”. We just do casual rhodium
plating on finished goods, not production. We use plain old everyday
copper wire for the work - it works just fine. We use plain old
everyday fingernail polish for masking. It also works fine, you can
see it (red) and it comes off easily and completely in acetone. If
you touch the anode to the cathode, whether directly or by touching
the side of the container, you’ll probably blow the fuse. You can
also electroclean with a glass beaker and a stainless steel
anode/cathode - there is cleaning and then there is stripping. It is
better, of course, to try for the best, but we don’t even use
distilled water, we just use tap water. The more plating you are
doing, the more important it is, but for us it works just fine. As
with all things, you get your piece clean, turn on the rectifier, and
dunk it in - it doesn’t have to be an ordeal. Gold plating is much
trickier and more involved, but rhodium is simple, easy and fairly
painless. The old fashioned way of drying goods is to use fine
sawdust - immerse the part in it, and it will just dust off when it
dries, without spotting. There is a steamer out now (try Otto Frei)
for about $50, aimed at consumers, but it’s better than no steam.
Lastly, your question about diamonds falling out begs the question
of, “Well, why would diamonds fall out if they are properly set?” We
use plastic sieves, which have been harder to find in recent years,
and also a screen over the sink drain, and also a trap in the drain,
for that…

http://www.donivanandmaggiora.com


#6

Hello Rahul,

All very good questions.

  1. Because rhodium is a highly acid solution copper can quickly
    contaminate/ruin it. If using copper always preplate with a nickel
    or gold solution first. Stainless steel will not contaminate rhodium
    that’s why it’s recommended. As for the leads, I would have an
    alligator clip attached to both negative and positive and then these
    connected to the handling wire and anode. This makes for a quicker
    disconnects, but is a personal preference.

  2. Yes, you can use a stainless beaker as it will act as your anode,
    but care must be taken not to touch the beaker (or anode) with the
    work while plating as it can leave burn scares on your piece. Also,
    depending on the rectifier, crossing the leads can cause possible
    shorting as well.

  3. You got me there, but I did find this info: Nitrocellulose
    lacquers produce a very hard yet flexible, durable finish that can
    be polished to a high sheen. Drawback of these lacquers include the
    hazardous nature of the solvent, which is flammable, volatile and
    toxic, and the handling hazards of nitrocellulose in the lacquer
    manufacturing process. Lacquer grade or soluble nitrocellulose is
    closely related to the more highly nitrated form which is used to
    make explosives.

  4. I’m not sure if the addition of any type of pigment or coloring
    agent will effect the curing or durability of this product. Perhaps
    some of our chemist friends can interject?

5a. Always have a dedicated distilled water rinse for each and every
solution. As your plating solution starts to loose volume and the
water content evaporates you can add the dedicated rinse water back
into the solution. Always be diligent about covering and protecting
your plating solutions as well as your rinse waters.

5b. The only time it’s really necessary to use distilled water is at
the beginning of the plating process, or after the electro cleaner
and there after.

  1. All settings should be checked and perfect before any other
    process begins.

  2. Perhaps, but if proper applications are followed it should not be
    a concern.

8/9. No, place item in absorbent cob meal and agitate for a few
minutes. This will dry your work and prevent water spots.

Feel free to call me or e-mail me off list if you wish.

Thackeray Taylor
Rio Grande Technical Sales & Support
800-545-6566 ex 13903
technical@tbg.riogrande.com


#7

hi,

I want to try electrocleaning a sample item for the first. I have an
S.S. anode thats about 8 inches X 2 inches, sufficient enough for my
item size. At what voltage should I set my rectifier. I have turned
the ampere knob to the maximum so that I just have to control the
voltage and the amperage takes care by itself. Is agitation required
while electrocleaning. Or can I just leave the piece inside with the
handling wire bent over the beaker wall. How many seconds or minutes
should I electroclean. I have seen some platers hang a wire right
below the lowest part of the jewelry. What could be the reason
behind that. Once i mix the electrocleaner in the water it, the water
looses its transparency gives an unclear yellowish (as if its dirty)
color. How, then, do i get to know when the electrocleaner actually
gets dirty and needs to be replaced. Someone told me that crocodile
clips corrode with the fumes emanated during plating. Whats the
solution to this problem.

Can i have the same rectifier simultaneously wired to the
electrocleaner bath and the rhodium plating bath and perform the
taskes separately.

I am interested in learning more about techniques of wiring of the
jewelry (racking/ jigging). I believe its very important for
companies with mass production. They plate many items by wiring many
items togther rigidly. Can you offer me a source (book/ website) I am
using a magnetic stirrer for agitation. It has a built in hotplate.
can i heat the beaker on it with the teflon inside the beaker even in
case when i am not stirring the solution and the teflon is lying
idle inside. Will the heat not damage the teflon.

Thanks
Rahul


#8

Hi,

Thanks for your mail. And I have taken care of the format.

I tried experimenting electrocleaning with a large silver necklace
(not worn for 15 years, so it was tarnished!!!) today. First I
separated a small section (say 10%) of the necklace (by opening the
joints) from the main body and electrocleaned the two sections
separately. I found that the small section cleaned much better. Not
being able to get a similar cleaning in the larger section, I even
tried increasing the voltage upto to 10 volts and even
electrocleaning it for nearly 10 minutes keeping the current knob at
the max. level and making variations in the voltage knob only. Still
it could not match the whiteness of the smaller section. I used the
same anode in both cases i.e. approx. 8" X 2" s.s. anode. I used a
glass beaker.

Is the difference because of the size of the anode (the size of the
larger section is much much more than the surface area of the anode
while the surface area of the smaller section is lower or equal to
that of the anode.

Why did it not help even I increased the voltage to 10 volts. Does
it not increase the current density?

Will I get more current and and even distribution of current if I
attch more conducting wires evenly spaced in the larger section. Or
is the current and its distribution the same even when i attach just
two wires each at the two ends of the necklace.

The cleaning would have been better if i had used an s.s. beaker.
But couldn’t have i achieved the same result using a smaller anode
but a larger voltage.

Thanks
rahul


#9

Hi,

  1. What should the plating time for rhodium plating. I am plating
    rhodium directly over gold base.

  2. To avoid burning/ darkening of the plating, Is it advisable to
    plate at a voltage with marginal cavitaion and therefore greater time
    taken for plating, or, a higher volltage witha greater activity but
    having a greater risk of burning. How do I make a jusdgement of the
    optimal voltage.

  3. I plated an old ring with rhodium that already had rhodium
    plating from before. I found that the plating darkened after that. Is
    it because rhodium done over existing rhodium platings darkens the
    surface or does it have to do with polishing of the item?

  4. I had applied lacquer on the object. Much to my surprise, after
    dip plating in the rhodium solution preceded by alkaline and acid
    cleaning, i found the plating adhereing on areas that I had masked
    with the lacquer. Why would that happen? What are the ways I to avoid
    it?

After applying the lacquer I had not subjected the item on any
external pressure such as ultrasonic and electrocleaning. These
steps had already been undertaken before application of lacquer.

  1. I am and new person in this field. Generally my plating have a
    dark appearence inspite of using brand new J2 (umicore) solution.
    What could be the reasons associated with this.

  2. I find that the plating produced by pen plating is darker and
    less brighter that dip plating. Is that true? If yes, Why so?

  3. How does alkaline cleaning and acid dipping activate the surface.
    I thought they only cleaned the surface. But does it also activate
    the surface? What is activation? ( i know i am going into
    theoriticals but it is important for my knowledge)

  4. How long should I dry the item after lacquering

Thanks
Rahul


#10

Hi,

I tried electrostripping/ electropolishing for the first time today
and was quite saisfied with the final result.

However, I have a few queries. Please could you help me withe the
same:

  1. First I electrocleaned a pendant made of silver but plated in
    gold. Next I made it the anode and stripped it the in same alkaline
    solution for 10 -15 seconds, each strip for 1 second and the same
    voltage i had used too clean. Then I made the piece the cathode and
    electrocleaned it. To my surprise, while electrocleaning now, I found
    that piece developed black marks (like carbon) mainly on the edges. I
    changes the polarities again and stripped again for 15 seconds with 1
    second cycle. The black marks faded little bit. Then I rinsed the
    item thoroughly and found the black mark coming off, and the piece
    started shining. While I was happy with the end result, I don’t
    understand why the piece got burnt when I electrocleaned it the
    second time. I had thought that it was more likely for the piece to
    get burnt while stripping, not while electrocleaning The voltage I
    was using was 2.3 - 2.5 volts ( not high) and anode was 8" X 2". The
    item was a medium sized pendant.

  2. While the bubbling was visible during electrocleaning, no
    bubbling was visible in the reverse process. How then can i know that
    the current is passing and the piece is being stripped. Considering
    this, how can I set the voltage while stripping (since there was no
    visual observation of bubbling)

  3. Can i use the electrocleaning solution for cleaning as well as
    stripping.

  4. Can electrostripping be used as an alternative to mechanical
    polishing for worn out items.

  5. Do alkaline solutions attack stones like peridote, pearls and
    jade. Or do acids attack?

  6. I have an item in which black wax/ dirt seems to have been stuck
    below the diamonds. I tried ultrasonic cleaning keeping the backside
    exposed to the waves to give easier and better penetration through
    the azures. But it did not clean. Then i tried electrocleaning. Even
    then it did not clean. Is steam cleaning the only alternative left
    for me. Since I do not have access to the same is there any other
    method i can adopt.

Thanks
Rahul


#11

Try using lye to clean the azures. It may take some looking but it
can be found on ebay. I heat 1/2 a cup of water, put the item in, and
then add roughly 1 teaspoon of lye. Stand back as you put the lye in
it will start a chemical reaction as soon as it hits the water. Let
the item sit for a few hours then ultrasonic lightly. Should be good
then. Oh, and dont breathe the fumes from the lye reaction. Lye is
also known as sodium hydroxide.

Stanley Bright
A&M Jewelers
Baltimore, MD


#12

Hi,

Try using lye to clean the azures. It may take some looking but it
can be found on ebay. 

If you live in the US, most hardware stores stock lye (sodium
hydroxide). If you can’t find it there, check your grocery store for
the crystal/granular form of Draino. It’s mostly lye.

Dave


#13

I used to get in the Red Devil brand-- nice clean plastic jar. Then
when I ran out…my local grocer didn’t have any. Neither did the
other stores near by. So I went to home depot and the drain cleaners
they had did not list lye in their ingredients list. I think it’s the
same story with the plastic model glue we used to use as kids to put
together plastic model cars. I did find it on Ebay though from a
chemical distributor.

Stan


#14

In my area, I have been told that lye is becoming more difficult to
get directly from the grocers/hardware shelf because it is used in
the process of making methamphetimine. Also, alot of mass
merchandisers are starting to pull lithium watch batteries from the
countertop displays, because they also are used in the meth
manufacturing process.

Ed in Kokomo


#15
In my area, I have been told that lye is becoming more difficult
to get directly from the grocers/hardware shelf because it is used
in the process of making methamphetimine. 

I am becoming active with the biodiesel community, and we are having
the same problem; Red Devil Lye is almost impossible to buy off the
shelf any more. The irony is that lye is the chief ingredient in many
drain cleaners, and folks who cook meth often have no problem with
just using Drano for their lye and matchheads for their phosphorus.
The resulting brew is probably pretty toxic, but whatthehell. Meth is
no health food even when it’s clean. Biodieselers, OTOH, tend to be
much more concerned with what they put in their tanks than tweakers
are with what they put in their bodies, so we want good, pure lye.

There are wholesalers who can hook you up with good, pure anhydrous
lye. You will probably need to purchase at least fifty pounds,
though.

Oddly enough, sources for methanol off the hardware shelf are also
drying up, and AFAIK this is not used for any sort of recreational
drug manufacture. It IS used for brewing biodiesel, though. Some of
us are wondering if this is just to squeeze the homebrewers of
biodiesel, as it has to really irritate Exxon-Mobile that we get our
grease for free and crack it into a relatively clean-burning fuel for
60 cents a gallon.

Lee


#16

Lye dried up in the stores for a while here in Texas. Lately it has
been found at Lowes, but not at Home Depot. It also showed up again
at HEB a large Texas grocery chain.

Methanol has less home type use and is toxic and causes blindness
when drunk…

It has little home use by itself.

I suspect consumer liability issues.

Also the nature of the material itself can be the reason for its
difficult availability.

No conspiracy – but if you use homebrew biodiesel with out
registration and federal and state road tax payment you can encounter
big problems at the federal and state level.

jesse


#17

From what I understand, lye can be used to make some kinds of
explosives. So it’s getting harder for people to get for legitimate
uses (like soap making).

Elizabeth Schechter
RFX Studios


#18
From what I understand, lye can be used to make some kinds of
explosives. So it's getting harder for people to get for
legitimate uses (like soap making). 

More likely, it’s harder to find because it’s one of the chemicals
used by the folks who’re making crystal methamphetamine in their
illegal drug labs…


#19
From what I understand, lye can be used to make some kinds of
explosives. So it's getting harder for people to get for legitimate 

It is not explosives that are the problem. Lye is one of the needed
ingredients for producing methamphetamine the worst drug problem
this country (USA) has. This is why it is no longer on the local
store shelves.

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


#20

Hi,

I have the following queries:

  1. I plated an item which had lot of recessed areas and the plating
    did not happen initially in recessed areas until I increased the
    voltage further. But that obviously resulted in uneven thickness of
    the plating. I know its because of uneven current density but is
    there any way to enure uniform thickness throughout the piece, even
    when the piece has lot of recessed areas.

  2. The rhodium solution gets trapped in the recessed areas and even
    sudden jerks/ shaking the pieces does not remove it. Thus there is
    lot out drag out of the expensive solution. Of course the drag out
    di-ionized water can be re-used but i prefer getting the solution
    back into the rhodium bath. can anyone suggest a solution.

  3. How do I remove rhodium from a piece of jewelry to get back the
    gold base. Is there anyway I can electrostrip rhodium. If not, whats
    the solution to this problem. I have customers who change their minds
    after getting their pieces rhodium plated and want the gold base
    back.

  4. Why does a gold plating done over rhodium plated object have very
    less longivity.

  5. Whats the safe/ best way to polish chains.

Thanks
Rahul