# Anodize Titanium!

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Learn how to anodize titanium at home using only a few simple things that you probably have lying around.

I'll walk you through how I anodized my new titanium cyclocross bike.

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## Step 1: Materials

0. Titanium

1. Rubber gloves (to avoid/prevent electrocution)

2. Plastic bowl/bucket/container

3. Small piece of sponge (1 x 1 x 1 cm), or a small piece of cloth (e.g. small strip of towel)

4. Voltage source that can be adjusted from 20-120 V. I used a commercial lab bench supply, but most people don't have these lying around the home. A good solution is to buy twelve 9 V batteries and connect them together in series. This allows you to adjust your voltage in discrete 9 V increments, or you can add a couple smaller voltage batteries in series as well.

5. Alligator clips to connect to your workpiece

6. Comet cleaner (I used this because it is cheap, i.e. less than a dollar), baking soda, TSP (trisodium phosphate), ammonium-phosphate, or Borax. Basically, anything similar to these products. Coca Cola or Pepsi will also work.

We'll be using some simple chemistry and electricity to perform magic!

## Step 2: Get Things Ready

Fill up your plastic container with a few ounces of water.
Stir/shake it up a bit.

Put your rubber gloves on so you don't electrocute yourself.

## Step 3: Electricity

Using the color/voltage chart, connect a few batteries together to get the voltage corresponding to the color you want. Choose a slightly lower voltage (5 to 10 V) to test your voltage/color. I found that my method produces colors about 5 - 10 volts less than this chart (i.e. I got a nice blue at 35 V and pink at 85 V). Or adjust your power supply, if you have one.

Important note: once you go up in voltage and add another color (e.g. pink over blue), you can't go back to a color at a lower voltage.

However: The anodized layer (an oxide layer, I think) is pretty thin, too, so if you screw up or don't like it down the road, you can put some elbow grease into it and buff it out. Using scotchbrite, high grit sandpaper, or similar will brush/polish your titanium right up. What an amazing element.

Connect your alligator clips to the positive and negative terminals of your power supply or battery array.

## Step 4: Apply the Magic

Connect the positive electrode (alligator clip) to your piece of titanium.

Grab the small piece of sponge with the negative electrode. Try to make sort of a paint brush with it.

You may chose to take a precautionary measure and wrap tape around the alligator clip and sponge such that you won't short out your power supply on the titanium.

Or ditch the sponge and use a piece of cloth.

The object here is to have something that will hold a bit of the water/electrolytic solution that will be "painted" on the titanium.

## Step 5: Mask and Paint

I didn't want all of the titanium colored, so I masked it off with electrical tape. I'm sure most other tapes that won't absorb water will work just fine.

You may also choose to clean your titanium to remove fingerprints, dirt, etc.

Find an inconspicuous spot on your piece of titanium to test your color. Start with a lower voltage and increase it until you get the color you desire. REMEMBER: you can not get a color at a lower voltage once you've applied a color with a high voltage (e.g. once you get pink at 85 V, you can't get blue at 35 V)

I noticed the colors at the lower voltages seem more stable and consistent. You can see in the pictures that the blue is a nice, consistent, smooth color whereas the pink has a yellow hue to it (yellow comes just before pink when anodizing Ti) and is very splotchy (probably because I didn't clean the frame very well, and because the same voltage wasn't getting to the whole surface evenly).

## Step 6: Marvel and Awe and Make Your Friends Jealous

Some feedback from a bike forum I posted this on:

"I love you?

edit: seriously though that's cool as two dogs " - Nick!

"Whoah, that does look real nice though. " - DonPenguino

"That looks amazing man." - Mr. Panda

"That is really cool!" - sage

"I'm gonna cry, that's beautiful. " - Charlie Short

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## 44 Discussions

Are you using the comet solution as an electrolytic cleaner?
Is the electrolyte just H2O? If so, should it be RO or di?

The comet is mixed with water to form an electrolytic solution.

If I have 1 gallon of water, how much trisodium phosphate should I add? I am anodizing titanium. Thanks for your help!

For either TSP or Borax, about 5g/l (5 tsp/gal) is a good concentration.

I've been "fiddling around" with anodising Titanium, as i make a lot of stuff from it..

I used a 24V DC PSU, which gives me a purplish dark blue that i really like
Recently i found a 120V DC Powersupply: https://www.ebay.com/itm/KPS1203D-Adjustable-Mini-...
at only 75 USD..
and i found a Youtube clip from a guy that uses the same PSU:

i like the colours on your bike..
I've also seen a video about Multi-Etch, that seems to be the "go-to Stuff" to etch titanium prior to anodizing, but someone stated white vinegar will also work.

Hey goldscott, I have a question about the power supply. I looked up that model in the picture and it only shows 0-30V. I dont know that much about electricity, but how did you get that to 110V? I want to buy this for some custom knife work.

2 replies

The PS that I posted was just an example. A proper lab supply that goes to 100+ V is pretty expensive. That's why I suggested batteries.

Or maybe you could make one with a grid voltage (usually 230 or 120 V) to 85 VAC RMS (which convert to 120 VDC) transformer (which you could wind yourself or buy), a full bridge rectifier (you can either buy one or make one with 4 diodes), and a big capacitor. Just keep in mind that this is dangerous, and you should have some experience with electronics before doing this.

Great tutorial, I will be trying this on some of my broken frames. As I have several tig welders do you think there will be anyway to use one as the power suppy?

Thanks! I don't think TIG has the correct kind of power supply for this. You want to be able to set a constant voltage, not current.

The colors obtained by this method are "interference" colors that arise because the top surface of the somewhat transparent titanium oxide has a reflectivity (for light) that is comparable to the reflectivity of the titanium metal that is under the oxide. The colors have some similarity to the "temper colors" that you can be seen on plain carbon steel when it is heated. To get this effect requires two things :

1. the oxide thickness is roughly the same length as the wave length of visible light

2. oxide and metal have similar reflectivity for visible light.

It won't work for aluminum because aluminum oxide isn't reflective enough.

The wavelength of light varies with it's color.

For more, google "carbon steel temper colours"

pdubya, BSc, MSc, PhD (all in metallurgy)

Did it work? Anything you'd recommend?

I spoke to some metalsmiths at my local makerspace and they told me I could get the bluing effect on titanium with a propane torch, so I think I'm going to go with that method.

where can i buy the power supply? i see a lot of power supplies but most only goes upto 15v and the highest i've found only goes upto 90v. help please. thank you