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Anodzing Power Supply


#1

After exhaustive searches for parts to build a DC power supply for
anodizing titanium and niobium, I have found an inexpensive
commercial unit that is working great! I didn’t find any other
commercial units that came close to this price and performance. I
don’t think I could have saved any more money building it myself. I
sure save a lot of running around

It is from Circuit Specialties Inc. in Mesa Az. 480-464-2458 It is
model SCI 12001X, a 0-120 volt DC, 1.0 amp supply

It has a lower current capability than those spec’s on some of the
"build it yourself" descriptions, but I think larger current models
are probably only useful for larger production runs.

It is $109.00. Prompt delivery…on-line payment find it at their
web site at web-tronics.com a direct url is
http://www.web-tronics.com/30serdigrobe.html

Hope this helps anyone who wants to get started with this process.

long time lurker…
Rick Sullivan


#2

First, I am happy for Rick’s success with his quest -but it brought
an old question of mine to the surface. Any of you more experienced
or learned folks who have a moment, please answer my question.
Thanks!

I am writing from a position of near-perfect ignorance about
anodizing, electroplating and any other processes requiring DC power,
but I have always wondered about whether an ordinary battery charger
could do the job. They do put out DC, don’t they? - and some of
them have controls with which to vary the output amperage. I guess
there are some processes which require very precise control of output
power but I also imagine that there are other processes in which
higher or lower power levels simply affect the elapsed time to reach
the desired result. So - I am just curious about this - You never
know when I might decide to do some kind of electro-something and
it’d be nice to .know whether to let this fantasy grow or send it
packing.

Thanks for any comments or enlightenment offered!

Marty in Victoria BC where it might rain some day.


#3
 I am writing from a position of near-perfect ignorance about
anodizing, electroplating and any other processes requiring DC
power

That pretty much describes me too, which leads me to ask when or how
do you know if the plating solution is contamenated? Specifically
rhodium. I haven’t noticed any problems and the plating seems to
look fine, but there is this funky looking black slime like substance
in the bottom of my beaker that I have no idea how it got there.

Anybody, smarter than me (which should include the entire list) have
an answer for this?

Thanks,
The Dr.
(Director of Romance)


#4

Battery chargers are rectifiers and anodizing and plating power
suppliers are rectifiers too. Battery chargers are ok although the
power supply people may say otherwise – after all it is their sales
loss.

For a LOT on anodizing aluminum see:
http://www.focuser.com/atm/anodize/anodize99.html

For plating and electroforming you will want some way to control and
read the current. There are bench power supplies made for electronic
test benches that do provide these functions. Some are expensive –
some are not. see:

tinyurl.com/4gnev

The voltage requirements are low – cell voltages for plating are
usually about 2 volts. The key is the current as it is what causes
the metal deposition. Currents for jewelry sizes are proportional
to the object surface area and will be low for single objects
often less than 1 amp.

You can find surplus computer type power supplies that are very cheap
but these are " switching power supplies " and you are better off
with a " linear power supply".

Power supplies for coloring reactive metals are higher voltage than
these since they vary the interference film thickness ( color
change) by going faster with higher voltage.

You do need to know what you are doing!!!
jesse


#5

Thanks to Rick Sullivan for the lead (so to speak) on the low-priced
power supply for anodizing. I have been lusting for Reactive Metals
new digital unit, but cannot afford it. This one costs 1/4 as much
and seems to have more adjustability!

But before taking the leap, I want to ask Rick whether he has found
any shortcomings with it, and Bill Seeley what I may have overlooked
about his unit, since I am a longtime and loyal customer of Reactive
Metals.

Rick-- the website does not seem to say (though I don’t really
understand the arcane language of electronics) by what increments
you can adjust the amperage (not the voltage). Can you enlighten
me? Do you understand the function of the “constant current” button?
Are you thrilled with the performance (and have you used some other
unit for comparison)?

Bill-- is there something I am overlooking in my evaluation of these
units?

Anybody else out there with a comment?

Thanks!
Noel


#6

Hello Marty, For many years, I used a 6 volt battery charger for
gold, rhodium and silver electroplating. This is too much voltage
for copper, so I used a flashlight battery. They worked fine. As a
matter of fact, my dad always used a 6 volt lantern battery for the
gold, rhodium and silver. Have fun. Tom Arnold


#7
But before taking the leap, I want to ask Rick whether he has found
any shortcomings with it, and Bill Seeley what I may have
overlooked about his unit, since I am a longtime and loyal
customer of Reactive Metals.

Yes, Reactive Metals has been a super supplier! I considered sending
them this off line so they might re-sell it as a low cost
alternative, but the price was so low it did’nt seem that it would be
worth their effort.

 the website does not seem to say (though I don't really understand
the arcane language of electronics) by what increments you can
adjust the amperage (*not* the voltage). Can you enlighten me? Do
you understand the function of the "constant current" button? 

I have not used the constant current button but don’t think it is of
much use in my applications , unless you wanted to slow down the
process. The constant current function maintains a constant current
out of the supply as the resistance of the load changes. The "load’
in this case is all devices external to the supply output (leads,
TSP solution, anode and cathode materials). The current output of
this supply is not adjustable beyond the use of this CC button.

The current should only affect the speed at which the oxide film is
formed. I find that at lowest voltages it does take a little more
time to color the piece. Since power3Dcurrent x voltage (P3DIE),
the power to form oxides is less because the supply is limited to 1
amp of current. After 10 volts or so, the piece/pieces color very
fast. The voltage, not the current, determines the thickness of the
oxide formation, and thus the color.

The voltage adjustment sensitivity is pretty decent. I can adjust
to tenths of a volt. The supply sold at Reactive metals seems to
have a much finer adjustment capability for both current and
voltage. These feactures might be good in a production environment.
Also, this would be worthwhile if we knew the exact setting for
each color, but there are too many other variables in the surface
preparation to predict with any accuracy. I bought a “how to” video
tape from Toika Bridges ( http://www.artcraftworld.com/titanium.htm
) that is excellent, and she recommends experimenting to correlate
voltage with color.

      Are you thrilled with the performance (and have you used
some other unit for comparison)? 

Yes! I was concerned that 1 amp might not be enough. All the how
literature used 2 amp supplies or more. I took a financial risk
buying the lower amp supply, and was blown away at how well it
worked…I had to share my experience.


#8

OK, time to chime in on this. Let me start out saying I search for
new and better power supplies all the time. There is one of these
units on my test bench now. It is a switching power supply (for the
geeks). Electronically it is at the bottom of the range of solid
state equipment. So far it works fine. I will carry it to some
workshops and use it in our studio and see if it holds up. Anodizing
is hard on a power supply. This one clicks and klacks some when
drawn to its limits. Time will tell. Some times you get what you pay
for.

Our current solid state anodizer is a switching power supply too. If
I add the “Circuit Specialist” unit to our line it will still cost
$40 - $50 more then the price being talked about here. They do not
discount worth a darn unless I buy 100 of them and I do have to make
a buck. You, the consumer, will get “value added” in instruction and
support. It has always been our SOP to keep anodizers priced as low
as possible. It doesn’t matter how much metal we have in stock if
you do not have the resources to use it!

A short primer on anodizing:

When you pass positive voltage through a reactive metal in suitable
electrolyte oxygen is released on the surface. Being reactive the
metal absorbs the oxygen to form an oxide. The oxide thickness is
controlled by the pressure or voltage being applied. Amperage in
this system controls how fast the process happens. Low amperage+
slow. High amperage = fast. The difference being only seconds. Low
and slow allows the use of very fine brushes and very subtle
variations in color.

The oxides of the reactive metals are transparent. Very transparent.
They have a higher refractive index then diamond. This oxide
generates the colors through thin film optical interference. The
thickness of the oxide determines the color. The thickness is
controlled by the voltage being applied. This is the type of color
you see in oil on a wet street and in some insects.

Interference colors happen when there is a reflective surface
overlaid with a thin(angstroms) transparent film. Light strikes this
surface and some reflects off while some goes through the film to
bounce off the substrate. This light is now delayed as it reappears
at the surface and “interferes” with light currently bouncing off
the upper surface. Part of the white light energy is lost and a
color is observed. So, the thickness of the oxide determines the
delay(color) and that in turn is controlled by the voltage applied.
As an aside, a battery charger could produce a 6 volt or 12 volt
color.

That is about as short as I can make it. More available if you want
it.

By the way RMS has moved a few miles down the road. The old school
building we have been in for ages is for sale. It was time to look
for new digs before something happened and we were left without a
home. We are in a newly remodeled space in Cottonwood , AZ next to
the airport. It is very nice with carpet, high ceilings and air
conditioning. The post office box and all the phone numbers are the
same.

Bill

Reactive Metals Studio, Inc.
PO Box 890 * Clarkdale, AZ 86324
Ph-928/634-3434 * Ph-800/876-3434 * Fax-928/634-6734
E-mail- @Michele_Deborah_Bill
Catalog- www.reactivemetals.com


#9

Hi, Bill (and hi to Debbie and Michele as well-- we met at SNAG–
I’m the one who gave you my niobium and silver pins)

Thanks for “chiming in”. I appreciate the frankness of your
response. I am still confused on one issue, however. If I read
right, the unit you sell functions at either .5 amps, for 0-60
volts, or .25 amps fpr up to 120. This makes sense to me, because if
I go too fast at high voltage, the workpiece sizzles and pops and
gets grey, mottled areas. As you said, low and slow for better
control. The “other guy’s” unit has a digital readout for amps, and
a button to adjust them up or down, though I don’t know by what
increment. It seems to me that this adjustment is very important,
because the larger the workpiece, the slower the process at a given
amperage and voltage. If I up the voltage to speed things up, I’m
likely to overshoot my color, so I need to be able to adjust the
amps. The “current limiter” on your older mini units does this
(right?) It sounds as though your fancy unit only has two options
(the mini has three) and the other unit has…?

If I sound a bit muddled, it is only because I am. Meanwhile, I’m
working at home with a unit you sold ages ago that is basically a
build-it-yourself kit product, bought cheap second hand, and it is
literally falling apart. So I am very interested in the outcome of
this discussion. I dream of the finer control I imagine these
digital units provide. So any help and clarification is much
appreciated.

By the way, you don’t have any used units you want to sell, do you?
I’d really rather work with you if I can.

Thanks!
Noel


#10

The higher voltage (100 volts +) rectifiers are not necessarily
safe as they stand. This is particularly true for inexperienced
non technical users. These units should have an isolation
transformer between the input AC line and the user and they may
often not have this as a result they can give life threatening
shocks. Less than 1 amp is enough across the body. Auto transformers
(variacs) do not provide isolation. Equipment in hospital use does
require isolation and some industrial users insist on it.

Lower voltage systems i.e. 12 -30 volts will normally have a
transformer isolating the user from the line. The lower voltages
also do not endanger life as the higher ones do.

jesse


#11

I have been an electronics tinkerer for almost as long as I have
been playing with chemistry, so I bring a bit of =93home-brew=94
thinking to this area. Unlike Bill from Reactive Metals Studio, I
have not spent my college and professional life perfecting the art
and science of anodizing reactive metals. He is THE expert in this
area, so if I say something that conflicts with his views, he will
be right. I took a workshop from Bill and was impressed. He has it
down pat. Good equipment, supplies and instruction and great ideas.
Be that as it may, I do not do enough anodizing to justify the
purchase of one of his power supplies, so I built my own.

I bought a variable isolation transformer (0-140V) and a bunch of
full wave rectifiers on eBay. I was concerned about shorting the
unit out as I was doing mostly paint brush anodizing and did not
want to keep replacing the little fuse, so I put a common light bulb
in series with the supply. If I short the unit out, this light
takes the load, lights up and tells me I have a short =96 no harm
done. The advantage of this unit is that it is powerful =96 8 amps,
high voltage for Ti, Nb, & Ta and lower voltage for electroforming,
plating and Al. It has full voltage control, which is as full a
control as one gets without filtering the ripples out. When the AC
voltmeter reads 40 volts, what I am getting is most likely 40 V RMS,
which varies from 0- to maybe 60 volts 60 times a second. With my
rectifier I get 0-30 V or so 120 times a second. I tried it with
smoothing filters, but I kind of like the way I can control the
colors over time with the cycling power. The disadvantage is that it
is bigger, heavier and a lot less convenient than the ones available
from Reactive Metals. (I still buy all my supplies from them)

Battery chargers will not work very well for anything but AL, too
much power for electroforming & plating, too little for anodizing =96
and no voltage control.

Marlin


#12

Hi Jesse,

I would be very careful with using any power supply not specifically
designed for anodizing and or plating due to the issues you raise
about line isolation. In fact I would suggest that any anodizing
power supply be run off of a separate isolation transformer to limit
the possibility of electrocution. Even low voltage power supplies
can kill you under the right circumstances so make sure you are
following all the appropriate safety precautions. Always use high
quality rubber gloves that you have inspected for holes or worn
areas while working with anodizing equipment. Make sure your wall
outlets are GFCI protected so that if there is a leakage path back
to ground the circuit will be interrupted.

Have fun but be safe,
Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#13

Marlin,

What you probably bought on ebay is a variable transformer or
variac. This is a type of auto transformer with a movable tap. They
are a very common surplus item. This is not an isolation
transformer and if it is what you have then you are running a high
risk of electrocuting yourself as there is no isolation from the
line power with this type of unit. It is imperative that you make
sure that you really have an isolation transformer in the circuit as
well as the variable transformer.

Regards
Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#14

Jim:

I do have an autotransformer, however the one I describe in the
previous post IS a variable isolation transformer. I did a voltage
test to confirm this. I also have a couple of stand alone 1:1
isolation transformers.

You are correct to email me as most variable “Powerstats” or
variable transformers are not isolation types.

Thanks again
Marlin


#15

Jim,

If possible, please give an easy explanation or an “isolation
transformer”. In my mind I am thinking that you have a transformer
with the inline/power feeding the primary side and the
secondary/output side feeding the transformer for the variable
voltage supply. Is this close?

Bill Churlik
@Bill_Churlik
www.earthspeakarts.com


#16

An isolating transformer is the “normal” type of transformer that
people think of when told that an item is a transformer. It has two
(or more) windings without any form of connection between the two.
Because the mains is Alternating Current (AC) that changes in voltage
and polarity (60 cycles per second in the USA), it induces a changing
magnetic field in the iron core. As a result of the alternating
(changing) magnetic field “cutting” the output transformer winding
(coil) a voltage is induced. A transformer will only work with an AC
supply current - it just burns out if DC is applied.

When manufacturers wish to make lighter and cheaper transformers for
higher voltages, they cheat a little and use an autotransformer. An
autotransformer shares a section of winding. So, for example, a 110
volt to 220 volt autotransformer basically has a winding for the 110
volt input and a second winding attached to it. The output is taken
across both windings ie 110 shared + extra 110 volt from induced
voltage. The drawback is that there is no “isolation” from the mains
supply. Isolation means that if you touch EITHER side of the output
of a 110 volt isolation transformer, you will not get a shock because
there is no common connection to earth. Another draw back is that if
a fault “burns out” the transformer (the shared section of winding
carries both the input and output current and is most often the fault
section), then often the ouput is just the applied mains. This may be
less trouble if the output is a higher voltage but if the
autotransformer is used to reduce the voltage (like 240 volt to 110
volt), then the output appliance gets fried very quickly.

Most Variable Voltage Transformers, (Variac and Powerstat are
registered trademarks of General Radio and Superior Electric
respectively), are autotransformers and have a single winding and an
adjustable arm with a carbon contact brush that rubs onto a section
of the winding that has had the insulation removed.

There are some that have a seperate isolated winding for the mains
input. These are normally very expensive and I have only seen these
advertised in the USA where they are produced for the electronics
repair industry. Sencore make some that are equipped with variable
current limits and other elaborate safety devices. Most technicians
that I have known simply use a seperate isolation transformer and
plug the variac into that.

I hope the simplified explanation is enough to understand otherwise
drop me a line and I’ll do a better explanation up.

Regards,
Brian.
Sunny Mackay NQ.


#17
please give an easy explanation or an "isolation transformer". 

Strictly speaking, an isolation transformer has equal wiring (gauge,
etc.) on both sides and is wound for a 1:1 ratio. If you put 110
volts in, you will get 110 volts out. The isolation comes in that
there is no physcial transfer of electricty from primary to
secondary. Rather, the electrical energy coming into the primary
winding is converted to magnetic energy, and that magnetic energy is
then converted back to electrical energy in the secondary winding.

[Not all transformers work this way because there is often an
electrical connection (read wiring) that is common to one end of each
coil.]

Del Pearson of Designs of Eagle Creek in Beautiful South Texas where
we are having lightening all around, but no rain.


#18
Isolation means that if you touch EITHER side of the output of a
110 volt isolation transformer, you will not get a shock because
there is no common connection to earth. 

Is this strictly true? Here’s another opinion when I asked about
such matters on an electronics design newsgroup:

From - Robert romapa@earthlink.net
Subject - Re: Power Supply (0-240v DC) Question
Newsgroups - sci.electronics.design

      How is reliance on an isolation transformer misleading and
      possibly dangerous, exactly? 
  The isolation transformer just "floats" the 240VAC away from
  GND. This means there is no longer a connection- as there is
  with the line fed voltage. This does nothing to protect you
  from getting zapped by the 240VAC. You have plenty of mass
  produced appliances that are perfectly safe because all expose
  metal surfaces are at GND- this protects you- it is impossible
  for these surfaces to rise above GND potential without blowing
  the fuse/ breaker. 
      GFI? 
  Ground Fault Interrupter. This is a device that can come in
  the form of a replacement line receptacle or circuit breaker
  that trips on imbalance of hot and neutral current. This
  translates into a trip anytime someone/ something makes a
  connection between a hot terminal and earth ground- the usual
  scenario for electrocution. 
      interlock switches? 
  Interlock switch is any switch that breaks the line voltage
  feed to your device/ load based upon some action. For example-
  if your apparatus is a tank with vented cover- and you want to
  protect someone from the exposed electrode terminals inside-
  you can wire the 240VAC through a lever arm switch that breaks
  the circuit when the cover is opened.- or the switch
  de-activates a relay that does the same thing. You can have
  interlocks for other reasons- say you can interlock on vent fan
  failure or some other safety related thing. 

  So just use sheet metal/machine screw attachments for GND
  wires to all your exposed metal surfaces, interlock the
  dangerous conditions as you see fit, and GFI either the
  receptacle of breaker. Forget the isolation transformer- a
  totally unnecessary expense. 
There are some [Variable Voltage Transformers] that have a
seperate isolated winding for the mains input. These are normally
very expensive 

Ground Fault Interrupters are far less expensive. Here in NZ they
are called a Residual Current Device.

Brian
In chilly deep winter (12C)
B r i a n A d a m
Auckland NEW ZEALAND
www.adam.co.nz


#19

Isolation means that if you touch EITHER side of the output of a
110 volt isolation transformer, you will not get a shock because
there is no common connection to earth.

Is this strictly true? 

All, in addition to the G.G., I also managed to get an A.S. in
Electronic Systems Technology while serving 20 years with the USAF
as an air traffic control radar technician. That doesn’t mean much
in itself, but please, if you don’t have a deep understanding of
basic electronics, DO NOT play with it! The above is most certainly
not true!!!

Practically all transformers are “isolation” transformers. However,
this term is most often applied to the transformers used for noise
reduction in audio and video circuits that employ a Faraday shield
to reduce spurious noise. If you value your life, leave the
isolation of your body in regard to exposure to potentially lethal
Alternating Current to the expert who designed the power supply. Is
your life really worth the $100 you saved?

James in SoFl who once got across 30,000 Volts, blew a 50A fuse, and
lived - but doesn’t recommend it for anyone, anywhere, anytime.

(For the curious, it was on an MPN-13’s Precision Approach Radar
H.V.P.S.)


#20

Hi Brian,

The answer you got is not quite the whole story. The current coming
into your house, studio etc is referenced to ground. This means that
if you take a voltmeter and touch one probe to a grounded surface
and one probe to a hot lead you will read the line voltage. If you
you were to be unfortunate enough to touch both a grounded surface
and the hot lead you would be shocked and possibly killed. Now if
you take the volt meter and read the output lead of an isolation
transformer and ground you will see no voltage indicated this is
because the output is isolated from the mains via electromagnetic
induction and there is no current path established between ground
and the isolation transformers output. If however you were to
measure between the leads of the isolation transformer you will see
the full mains voltage and if you were to contact both leads of the
isolation transformer you would indeed be shocked. It will not
prevent you from being electrocuted it only lessens the likelihood
because it is not referenced to ground and you need to contact both
leads not just one to get a shock.

Jim

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau