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Ok, we have
metal anodes, now we want to get the metal off of
those anodes and onto your part. For this you will
need a way to transfer that metal. Wahla! In comes
the Electroplating bath. A brief explanation of
what a bath is and what it does is in order here.
Grab your cup of coffee or whatever and sit a spell
to do some reading.
The
electroplating bath is the heart and soul of the
electroplating operation. If it’s off in its
chemistry then you start to have problems. If you
keep up on it and keep it clean it will give years
of good service to you.
The
bath allows the metal to be transferred from your
anode to the part you are plating.
Each
bath has different characteristics and ranges to be
operated in. Some take only .1 amps per square inch
and others (chrome) take at least 1 amp per square
inch.
With
out explaining the chemistry of ions, atoms and
pos. and neg. charged particles (this is only 101)
I will give a brief explanation of how a bath
works.
Initially
when your bath is made up you add chemicals such
as…. nickel sulfate, copper sulfate, and
chromic acid. In these chemicals are metal
particles that will plate to your part when you put
the electricity to it in the right manner. If you
did not replenish these little metal particles
eventually they would run out. To replenish them,
you put an anode in the solution and the acidic
nature of the solution slowly corrodes the metal
back into the solution. So as long as you keep
replenishing the solution with metal it will work.
There are some other variables that can change how
a bath works but that is deeper and should be
studied on your own from the books listed at the
end of this web page.
When
you use your bath most of them have a broad range
that they will plate in.
By
this I mean that you can use a wide range of
temperature and amperage to plate with. If you use
a higher temperature for plating your plating will
be courser grain and darker in color, but, It will
also plate faster.
***The
chrome bath is a bit more cantankerous and has a
very narrow plating range. ***
If
you use lower temperature to plate with you will
get a brighter smoother and tighter grain plate on
your part.
The
more amperage you use the faster you will plate.
But……The plating will be courser and you
can also go over board on the amperage and cook the
plating right off the part.
You
have to find your happy medium here.
When
you initially make up your plating bath, mark the
side of the container where the top of the fluid
level is. The reason for this is so as you use the
bath and the water evaporates off you can add
distilled water to bring it back up to where it
should be.
If
you are planning on using your baths a lot you will
want to learn how to test the acid/alkaline (pH) of
a plating bath. This can be done with litmus
papers, and to test specific gravity of the bath
use a hydrometer. (This is only needed if you plan
on using the baths a lot! I have never had to
adjust mine)
These
tests can be found in the recommended books
area.
To
heat up your solutions to the recommended operating
temperature use aquarium heaters or small beverage
immersion heaters. When you are done with the
heaters clean them off good. You don’t want to
mix the chemicals from different
baths.
You
will want to make a bubbler for your baths. What a
bubbler does is it scrubs the surface of the part
while it is plating and knocks off the hydrogen
bubbles that normally form during plating. If you
leave these little bubbles on your part you will
get pits on the surface of the part. I have found
it is best to use an aquarium or small air pump
with a rubber hose full of holes. You want the
holes big enough to make large bubbles. If you have
small bubbles they will only compound the problem
on the surface of the part. Make the bubbles large
enough to scrub the surface.
A
bubbler will also help keep the bath temperature
consistent through out the whole
container.
The
way that I clean my baths when I start to get
little floating things on the surface is to run it
through a coffee filter. Just use two buckets with
a holder for the filter.
Each
bath will work a bit different then the others. The
only way to learn this is just to plate away!
Practice on scrap pieces of copper tubing. Wreck
some pieces of tubing on purpose to see what it
looks like with too much amperage or too cold of a
bath. Don’t get discouraged!!!! Learn and have
fun.
All of these
baths can be scaled up or down but just make sure
to do it proportionally with all the
chemicals.
Behind each
chemical I will also put the chemical make-up.(The
capital letters and numbers) This will help you in
the future when you read books on
electroplating.
The reason
there are two types of nickel baths is that if you
put a piece of pot metal (zinc, aluminum, magnesium
alloy) in the regular Nickel bath, the part will be
eaten by the strong solution. The pot metal bath
does not plate as thick as the regular bath but
will serve as a good initial strike for the plating
of parts.
I will also
list the bath necessary for plating aluminum. The
following bath recipes are for copper, nickel,
chrome and zinc. When making up your baths put the
distilled water in the container first. Use only
distilled water because it is pure. You can warm up
the water to aid in dissolving the metal salts.
Then add the metal crystals and stir them until
dissolved. Finally add the acid last. Some acids
will react to the water by splattering and heating
up. So make sure you read your MSDS to know what
you are dealing with.
1.
Copper
2.
Regular nickel
3.
Pot metal stike/nickel
4
Chrome
ALUMINUM
BATHS
1.
Zincate
2.
Nitric acid
CLEANER
BATHS
1.
Sulfuric acid bath
2.
Hydrochloric acid bath
3.
Weak acid bath
4.Caustic
Soda bath
5.
Baking Soda bath
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Make
up.
*1
gallon of distilled water
*
Copper sulfate (CuS04)---32 dry
oz.
*
Sulfuric acid (concentrated) (H2S04)----7
oz.
(actual
weight, not fluid oz.)
*
Anodes---Copper
You
can use battery acid but it is not as
concentrated and you will have to add more
to get the level correct.
Operating
conditions
Operating
temp.---------- 75-150 deg. F. 24-66 deg.
C
Voltage/amperage-------
1-3 volts .1-.3 amps per square inch
Air
Agitation required
The
copper bath can be operated at a very wide
range of amperage and Temp. Typically the
higher the temp the grainier and rougher
the deposit. It will also plate faster at
higher temperatures. To get a nice tight
grain and a medium speed of deposit go
with 120 deg. F and .2 amps per square
inch. You can experiment with the copper
bath and see what different temp/amps will
do.
Use
this bath to plate to copper, nickel or
brass. It will not plate to steel,or pot
metal
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Make
Up
*1
gallon of distilled water
*
Nickel sulfate (NuS04x6h20)----- 40 dry
oz.
*
Nickel chloride (NiC12x6h20)----- 10 dry
oz.
*
Boric acid (H3bo3) 7 dry
oz.
*
Anodes-----pure Nickel
Operating
conditions
Operating
temp.---------- 115-120 deg.
F
Voltage/amperage-------
3.5 to 5 volts. -----.15 amps per square
inch
NOTE:
As your bath cools down, the boric acid
will precipitate (turn into granduals)
again. Dont worry, it will melt back down
when you heat the bath back
up.
Air
Agitation required
There
are many variations to this WATTS nickel
bath, but this is a good all round bath
for plating nickel. It will produce a nice
dove gray plate on your piece and can be
buffed to a very high luster. If you want
to make the plate a little bit brighter
add .30 oz of saccharine to the above
bath.
Use
this bath to plate to steel,nickel brass,
and copper.It will not plate to potmetal,
or aluminum without first zincating the
aluminum.
Do
not lift your part out of the bath to look
at it or you will break the flow of
electricity and the succeeding plate will
peel. If you do happen to break the
electrical bond simply reactivate the
nickel surface by placing it in the
SULFURIC ACID bath momentarily. Don't
leave it in to long or you will attack the
base metal.
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POTMETAL
STRIKE/NICKEL
BATH
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Make
Up
This is my
second type of potmetal bath. The first
one was giving me problems with some
potmetal off of my 55 DODGE. Since I have
switched to this formula I have had no
problems whatsoever. It is a very good
nickel stike bath.
*
1 Gallon of distilled water
*
Nickel sulfate (NuS04x6h20)----13.33 dry
oz.
* Sodium
Sulfate----------------------13.33 dry
oz.
*
Ammonium Chloride--------------4 dry
oz.
*
Anodes-----pure Nickel
Operating
conditions
Operating
temp.----------70 deg. F
Voltage/amperage-------
3-5 volts/.1-.3 amps per square
inch.
Air
agitation required
This
bath will put on a thin brittle plate of
nickel. This keeps the metal from being
attacked by the next plating solution. Do
not put on a heavy plate with this bath
because it is a very brittle plating and
it will crack if it is too thick. After
the strike coat (immediately after!) you
can plate with copper, reg. nickel and
then chrome.
Potmetal
Plating
Toursee
how its done!!!
Do
not lift your part out of the bath to look
at it or you will break the flow of
electricity and the succeeding plate will
peel. If you do happen to break the
electrical bond simply reactivate the
nickel surface by placing it in the
SULFURIC ACID bath momentarily. Don't
leave it in too long or you will attack
the base metal.
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Make
Up
*
1
Gallon of distilled water
*
Chromic acid (CrO3)----30-33 dry
ounces
*
Concentrated Sulfuric acid (H2S04)
---.30-.33 ounces
(By
actual weight of the acid, not fluid
oz.)
*
Anodes---Lead
Operating
conditions
Operating
temp.----------110-150 deg.
F
Voltage/amperage-------
4-6 volts/at least 1 amp per square
inch
Air
agitation required
The
Chrome bath has very poor throwing power.
That means that it may not plate in
recesses and holes. You may have to move
your part a lot and also add some lead
anodes closer to the part that is not
getting a full plate. As you also notice
this bath takes at least 1 full amp. per
square inch. So be ready to have good
heavy wires and hooks if you plan on
Chrome plating.
This
bath has a very narrow plating range. You
must keep the temp. up there or it will
bubble all day long and no plating will
take place.
****SAFETY
NOTE****
DO NOT BREATH THE FUMES FROM THIS BATH THEY ARE VERY HARMFUL!!!!Use
an acid filter respirator of have a fan
blowing the fumes away from
you.
BUY A FUME SUPRESSENT TO ADD TO YOUR BATH.
If
when you are plating chrome and you are
not getting any to plate on your part. Try
increasing the amperage or the temp of the
bath. If you get a hazy chrome plate your
bath is too hot.
To
read more on Chrome plating click to this
link
http://www.pfonline.com/articles/pfd0016.html
http://web006.pavilion.net/users/nickfull/chrome.htm
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The following
two baths are to help you plate aluminum properly.
Aluminum starts to oxidize as soon as you clean its
surface. The problem is that when it is put in the
next bath the plating will not stick because of the
oxidation. To work around this you will put a very
thin layer of zinc on the aluminum. This will
protect it until it is placed in the proper bath.
Once in the bath the acids will eat away the zinc
coating and expose the fresh aluminum under it. The
plating will then stick very well.
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Make
Up
*
1
Gallon of distilled water
*
Sodium Hydroxide (NaOH) (lye) ---60 dry
oz.
*
Zinc Oxide (ZnO)------12 dry
oz.
****SAFETY
NOTE****
Use
caution when handling this. The Sodium
Hydroxide will heat the water up and can
cause serious burns on your
skin)
*
No anodes needed in this bath. It plates
by immersion.
******First
add the Sodium Hydroxide to about half the
water, then add the Zinc oxide before it
has cooled down. Finally add the rest of
the water.******
operating
conditions
Operating
Temp.----77 Deg. F.
Dip
the part into the bath for 30 seconds to 1
minute. This will cover the surface with a
thin layer of zinc. It is recommended that
you double Zincate your parts. To do this
after you have zincated the part once,
rinse, then dip it into the Nitric acid
bath to strip the zinc layer off. Wash,
then redip the part in the Zincate
solution again. Now you have full coverage
on the part.
The
reason for zincating is to protect the
base metal from oxidation before you get
it into the proper nickel bath. This is
commonly used on aluminum. I have had to
use it on some pot metal because of the
high aluminum content in the metal.
You
do not want to put a real heavy layer of
zinc on the part. Just enough to cover it.
It will be a nice dove gray when you
remove the part from the
bath.
No
air agitation is required.
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Make
Up
*
1
Gallon of distilled water
*
Nitric Acid (HN03)----------32 fluid
oz.
****SAFETY NOTE****
(Use
caution with nitric acid. It is vaporous
and burns)
Add
Nitric acid to the water
operating
conditions
Operating
Temp.----77 Deg. F.
Dip
the part into the bath. You should see the
coating of zinc come off almost
immediately. If it does not then add more
Nitric acid to the bath.
No
air agitation is required.
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The
purpose of the following baths are to clean and
prepare the surface of the part for the next
plating bath.
The acid
baths can also be used to strip the listed metals
off of the part. Be sure and rinse all of
the residual acid off of the part before continuing
into the next bath. It will cause problems later if
you don't.
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Make
Up
*
1
Gallon of distilled water
*
Sulfuric acid (H2S)4)-------9 fluid
oz.
****SAFETY NOTE****
Carefully
add the acid to the water. It may splatter
so wear your face shield, apron, and
gloves.
Take
care to not breathe the fumes created by
this or any other bath.
operating
conditions
Operating
Temp.----77-120 Deg. F. (The hotter the
bath the quicker it will
work)
No
air agitation is required.
This
bath is used to strip or activate nickel
plate. It can also be used to strip chrome
plate. Watch your part in this bath as it
can progress rapidly and begin to attack
the base metal.
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HYDROCHLORIC/MURATIC
ACID
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You may use either hydrochloric or MURATIC
acid for this bath
Make
Up
*
1
Gallon of distilled water
*
Hydrochloric/MURATIC acid ------31.5 fluid
oz.
operating
conditions
Operating
Temp.----77-120 Deg. F.
****SAFETY NOTE****
Carefully
add the acid to the water. It may splatter
so wear your face shield, apron, and
gloves.
Take
care to not breathe the fumes created by
this or any other bath.
No
air agitation is required.
This
bath is used for removing rust, deplating,
and surface etching copper and brass.
Watch the part when it is in the solution
as it can progress very rapidly and start
to attack the base metal.
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Make
Up
*
1
Gallon of distilled water
*
1 Teaspoon concentrated sulfuric
acid
****SAFETY NOTE****
Carefully
add the acid to the water. It may splatter
so wear your face shield, apron, and
gloves.
Take
care to not breathe the fumes created by
this or any other bath.
operating
conditions
Operating
Temp.----77-200 Deg. F.
No
air agitation is required.
The
primary purpose of this bath is to pickle
zinc alloy (pot metal) and aluminum before
plating if needed. If it turns your part
dark or black, scrub the part with steel
wool in cleaner and then plate immediately
with the nickel strike bath. Do not try to
plate the part with the dark film on it.
This is a very weak acid bath but it will
not only clean the potmetal but will also
activate the nickel if you still have some
on the part. I usually scrub the part
in the bath with a steel brush or 280 grit
sand paper.
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Make
Up
*
1
Gallon of distilled water
*
Sodium Hydroxide (lye).......8
oz.
*
Sodium Carbonate..............2
oz.
*Trisodium
Phosphate..............4
oz.
operating
conditions
Operating
Temp.----70-175 Deg. F.
This
bath can also be used as a electrocleaner
bath for steel and nickel.
If
used as a electrocleaner bath heat to 180
deg. F and set at .2-.4 amps per square
inch for about 30-45
seconds.
No
air agitation is required.
*****SAFETY
NOTE*****
Sodium
Hydroxide is extremely nasty stuff. It
will do major damage to your skin. Wear
your protective gear when mixing this bath
up. Mix about half the amount of Caustic
soda into your full amount of water. Let
it cool down. Then mix the other
half.
This
is going to be your all round cleaning
bath for most of your work. For non
ferrous metals (not magnetic) use the bath
at 140 deg. For ferrous metals (magnetic)
use it at the higher temperature of 175
deg.
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Copper/Brass
Electrocleaner
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Make
Up
*
1
Gallon of distilled water
*
7 oz. Sodium Hydroxide
*
12 oz. Sodium Corbonate
*
12 oz. Trisodium phosphate
operating
conditions
Operating
Temp.--- 140 Deg. F.
Set
amperage to .06-.2 per square
inch.
Clean
for approx. 20 seconds
No
air agitation is required.
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Make
Up
*
1
Gallon of distilled water
*13.3
oz. of hydrochloric/MURATIC acid
(NOTE!!!
It is 13.3 oz by weight, not by fluid
oz.)
operating
conditions
Use
at room Temp.
Activate
part for 30-45 seconds.
No
air agitation is required.
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Make
Up
*
1
Gallon of distilled water
*5-10
% by volume of sulfuric
acid.
IE:
A 2 gallon bath equals
2
gallons of water
25.6
fluid oz of sulfuric acid.
operating
conditions
Use
at room Temp.
Activate
part for 10-20 seconds.
No
air agitation is required.
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