Instructables

Make Silver Different Colors by Anodizing

video Make Silver Different Colors by Anodizing
How to Make Silver Different Colors by Electrochemical Anodizing.

Without using paint you can give a silver surface various colors by anodizing it.

WARNING: Anodizing solution is corrosive, so wear gloves at all times when working with it. It is also somewhat toxic, so keep it away from children and pets too.

To make the solution, just mix two tablespoons of sodium hydroxide (lye) and one tablespoon of sulfur with half a cup of water (~100mL). Stir for about ten minutes until the solution turns orange. Then filter the solution to remove excess sulfur.

You can get sulfur from online sources (including ebay) or from some drugstores. Sodium hydroxide is the primary component of some types of drain cleaners. But read the label carefuly, drain cleaners come in many types and alot of them don't have sodium hydroxide. You can also buy sodium hydroxide online, it's sold for making home biodiesel or homemade soap.

After you made your solution, thoroughly clean your silver article and place it into the solution. Attach the positive terminal of a 3V battery to the article and dip the negative wire into the solution. Move the negative wire around the solution to give the silver an even coat, or keep it in a single spot to apply rainbow effects.

What's happening is the electric current is oxidizing the silver and causing it to pick up the sulfur dissolved into the solution. As it does this it thickens and alters the way light reflects off the surface. What color of light is reflected is determined by how thick the sulfide layer is. The thickness of the layer is determined by how long you anodize it. So you can control the color by controlling the time you apply the current.

The process can be used to tint silver items to give them an antique look or simply just to make them exotic colors.

Practice before you do this on something valuable.

If you make a horrible mistake, you can restore the silver by electrochemistry at this link http://www.youtube.com/watch?v=vGCx9HZwYBo

Always use batteries for this process to keep safe. Also don't use higher voltage batteries, you might end up "burning" a layer of silver off your item and ruining delicate designs.

We've done it with copper, but the color is not as brilliant, silver gives the best effect for the video. We haven't tried it with steel and aluminum just goes dark without getting color.

Thanks for watching, subscribe, rate and comment!

If you like my videos, check out http://www.nurdrage.com
ommousa6 months ago

I want also to ask:

Would it work if I anodize a gold plated silver?

I mean if I have a silver piece that is gold plated and I want to combine the color of gold plating and anodizing?

ommousa6 months ago

Hi

I want to ask pleas:

  1. - If I want to anodize part of a silver jewelry, is that possible? to anodize half and leave half of it?

2. Is it possible to solder anodized silver? I mean to solder it after anodizing it? If yes, would that affect the color obtained by anodizing?

mastergabe1 year ago
will it work with unpure silver
Popopopper2 years ago
Can you de-anodize it by putting it into a solution of baking soda and salt in water with the aluminum foil?
Amadauss2 years ago
I am having the same issues getting the orange liquid to form. Have used as specified and tried the alternatives as suggested except for the heating in steel bucket. Just wanted to confirm what tool you used to stir the ingredients, and if you heated the misture while stirring? Thanks very much.
Brennn105 years ago
This is a really cool experiment. Sadly; coin counterfeiters practice this to get what is called a "tone" on the coin; something making it worth more.
Eirinn Brennn103 years ago
He's done video's too about electroplating coins :)
morgantoner4 years ago
I would like to know how anyone is getting sulfur to dissolve in water with lye or ammonia. It won't work. I love the results the video show but it's not possible with the components given. There has to be a variable there. You can use shampoo and get similar results but I would truly like to know how the doctor is getting the solution to turn orange. Soft H2O, hard H2O, ionized H2O, hot or cold makes no difference so please let's get to the bottom of the equation. I would pay to see it happen. Thanks for all of you videos. I have used a lot of them but this one does not work. Please help. clay.bingham@yahoo.com
NurdRage (author)  morgantoner4 years ago
Sulfur comes in various allotropes. In my video i used re sublimed sulfur. Is that the type of sulfur you used?
One other thing, I have a friend in California and he says he is getting the same toning effect without using any sulfur but says he paid over six grand for the process. I certainly can't afford sixty dollars much less six grand but I have been staying up night and day and reading all I can and trying so many different things and getting a little results but sinch you are a professional I was hoping that you may be able to help me out. It would mean an aweful lot to me and my family. I depend on this process for income and had to give up regular job to take care of my mother and I really need to get this right. Don't mean to give a sob story but letting you know how important this is. Thanks for any and all advice.
NurdRage (author)  morgantoner4 years ago
i don't care about sob stories, i care about science. What we need to focus on is that. No amount of sobbing gets a reaction to work. Trust me, i know this from personal experience. As for the sulfur, a dangerous, but more reliable to get it to work is to mix together the dry sulfur powder and the sodium hydroxide in a steel tin. It has to be steel, if it's aluminum it will be destroyed. Once the ingredients are in, heat the tin over a flame until the chemicals melt and carefully stir the mixture together. Once it's all thoroughly mixed, let it cool. Smash it into little pieces and then pour it into water. This is extremely dangerous because as it melts it's prone to sputter extremely corrosive and toxic sodium polysulfide. It'll burn your flesh off and leave wounds that are extremely slow to heal. Just think what happens if it gets into your eyes. It's the only way i know of that works with most types of sulfur. Do it at your own risk.
I used sulfur USP SUBLIMED POWDER
where do you get all your componetnts? thanks for answering and keep up da good work!
thesinner5 years ago
Nice write up. Sorry in advance, I'm an electrochemist/plater, so I figured I'd add to your stuff. If you don't have access to lye, unscented ammonia should also provide the alkalinity necessary to produce that AgO film. Be careful when activating your substrates, as these reactions emit hydrogen gas, which can be very flammable. You SHOULD NEVER oxidize aluminum with a high pH solution, as it will react rapidly and may cause an explosion. Just to note for other readers, there's no benefit for higher voltages across the plating/andozing bath. For your typical transition metal, anything above 5V is overkill. In the event you're getting too much resistance across your plating/anodizing solution, try heating it up or adding inert electrolytes or chelaters. Aluminum is actually the most popular metal to anodize. What's exceptionally nice is the voltage differential of an aluminum anode is enough to produce about 1-1.5 volts. If you anodize in a solution of an easily-reduced metal salt (like copper chloride), you will have enough electrical potential to simply connect a wire from anode to cathode to both anodize the aluminum and plate your cathode. The trick with colored, anodized aluminum is that you dope your dragout bath with an organic dye. It can fit between the cracks of the forming aluminum ceramic, giving a nice color. I'd imagine dipping a highlighter or sharpie in a small thing of water could make for some interesting colors. As for anodizing steel, it's gonna depend greatly upon the grade of steel you get. Cheap grades (mainly iron and nickel) are going to just turn an ugly brown. Of course, if you get enough current and voltage in there, it is possible to form magnetite (Fe3O4), which could be pretty sweet. I'll have to look into that one.
Hey Sinner can you give some real world help to someone interested in anodizing? I do chain maille jewelry, but anodized aluminum or copper are ,10 and up with many projects using 2-400 rings. I emailed a guy in PA that runs a telescope fabrication biz and short runs at the plater were too high, so he bought transformers, big flat tubs & dye and now sells small kits to hobbyists. Some folks say a trickle charger will do the trick, true? A coil is like a long spring, can I group a few to become the cathode? Will the anodize & dye "Take" where the sides of the rings touch to form the spring before they're cut loose? Thanks!
i would very much like to talk about the different agents to use to get the effect i am looking for and i have tried alcohol and some amonia but i need to know the amounts so that when the coin is dropped in the solution the coin doesn't begin to change colors without adding the electrodes. i know there must be some type of dillution process that needs to be done and how to give the rainbow effect that is shown in this video. i only work with silver and that is what i am interested in so if you can help please email me clay.bingham@yahoo.com
morgantoner4 years ago
the sulfur sill not dissolve in water. the lye is 100% and if you would let me know which type of chemicals are added to make the silver dissolve like amonia or alcohol and the percentages it would be a great help. thanks.
ruigiga4 years ago
  Hi,

  Just tried to do this experiment but it didn't work as expected. So I have a few doubts:

  1 - Do you heat up the solution, or the oven (is it a oven or an automathic mixer?) has not anythig to do with the experiment?

  2- Which are the exact cuantities for S and NaOH? or it does not to be so precise?

  3 - Does the type of water has any influence? (destiled water, de-ionized?)

  Cheers!!!


reedz5 years ago
I really like your videos. However I find the voice-mask to be fairly annoying, any chance of taking it off? Just for the readers/viewers
NurdRage (author)  reedz5 years ago
I find it amusing that everyone assumes it's a mask. Anyway, I am aware people don't like my voice and i tried pitching it up, but I ended up sounding like a 4-yeard old girl. which was even more annoying. If it bothers ya, you can go to the actual video and turn on subtitles. Then turn off the sound. That's the best i can do, until i can find someone else to voice over all my videos.
There is nothing wrong with your voice. If anything it is an excellent voice-over voice since it has character and is memorable.
reedz NurdRage5 years ago
... I'm so sorry... I had no idea...
NurdRage (author)  reedz5 years ago
haahah :) don't worry about it. The voice gives me character :)
dagenius4 years ago
how much silver do you have?!!?!??
lemonie5 years ago
(The voice is annoying) Would you like to speculate on the chemistry happening in here? L
NurdRage (author)  lemonie5 years ago
The entire of reactions is pretty complicated. The overall useful reaction is 2Ag + S --> Ag2S (where the 2 is a subscript) In actuality, the water itself also participates (which explains the bubbles comming off the black wire during the experiment). Then there are the various half-cell reactions at each electrode. The dissolving the of sulfur in the hydroxide to form aqueous polysulfide... ... it gets complicated.
I should think so, which is why I'm interested. The colours must be due to different thicknesses of suphide?
To format subscript use commacomma2commacomma, Ag2S

L
NurdRage (author)  lemonie5 years ago
Didn't i say that in the description?
NurdRage (author)  NurdRage5 years ago
Anyway, the chemistry goes something like this:

First, there is the addition of sulfur to the highly basic solution of sodium hydroxide. This forms an aqueous polysulfide from the action of the hydroxide molecules onto the Sx molecules. So you get something like

OH- + Sx --> HOSx-

The counterion being the sodium ions.

The sulfur being “soft” lewis base clusters around the silver. Eventually the positive potential is applied and the silver surface acquires a positive charge. The loss of electrons induces a half-cell reaction at the surface.

Ag --> Ag+ + e-

But since the polysulfides are already attracted to the surface they instantly react with the silver ions.

2Ag+ + 2HOSx- --> Sx + AgS + H2O

And this creates our silver sulfide layer.

The hydroxides are regenerated at the cathode when the water is electrolyzed.

2H2O + 2e- --> H2 + 2OH-

which then pick up the floating sulfur

OH- + Sx --> HOSx-

Yes, that makes sense I appreciate the detail (And yes you did mention thickness in the description, I must have read it a bit too quickly) L