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topic 1762

Anodizing titanium: amps, concentration, contamination, setup, problems

Current question and answers:

December 30, 2020

Q. Hello!

From reading some other threads, I understand that stainless steel will dissolve away in an anodizing bath. But if I am "painting" anodization onto titanium with a brush, instead of submerging it in a bath, would it be problematic to have stainless steel parts attached to / in contact with the titanium? I am new to this and would like to avoid dangerous electrical problems :)

Thanks so much for any insight!

Jean Huang
- Beacon, New York

December 2020

A. Hello Jean. It sounds like no problem to me.

By the way, those warnings you refer to were in regard to anodizing of aluminum with SS attached, not titanium with SS attached. Aluminum anodizing is done in very corrosive sulphuric acid. I don't know what would happen if you immersed an assembly of titanium and stainless steel in a titanium anodizing bath; it might depend on what electrolyte you use.

Luck & Regards,

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Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading

December 31, 2020

thumbs up sign Dear Ted,

Thanks so much for weighing in! I really appreciate it.

Happy New Year!

Jean Huang [returning]
- Beacon, New York

Previous closely related Q&A's starting in:


Q. I am looking for information on the relationship between applied voltage and the color obtained during the anodizing process of titanium. For example what voltage is required to obtain a blue coating, or a green coating, etc.

Thanks, Chris

Chris Gervais


A. Data for 6-4 Ti is not going to be the same as CP Ti. It also will not anodize as well because you are looking at 10% alloy. The aluminum will anodize at a much lower voltage than the Ti and will look different than the Ti. I think the Vanadium will not react or will dissolve. In short, I think you will get funky looking anodized parts.

You can get a how to do it manual from Reactive Metals Studio, Inc. in clarksdale , AZ


James Watts
- Navarre, Florida


A. Ti6-4 surgical instruments are routinely anodized for color coding. The first blue color appears around 28 V. The exact relationship between color and voltage will vary with each setup. You will have to experiment. If you are using titanium clips to hold the work, the anodized layer on the clip will need to be removed mechanically or in a dilute (5%) HF solution (handle with care) between each run.

Paul Vernon
Designed Materials Research


Q. I would like to know the anodizing solutions of titanium.

Actually it's the platinum titanium I am looking for. Do you have any information on that?

MINTEK - Zaire

A. Mr. Adams, please see topic 937 for a good discussion on that.

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Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha


Q. I am trying to anodize a large piece of 6/4 titanium, 105" x 16" x 3/4". I am looking for information on the amperage requirements and what difference I can expect from different solutions. Also, does alloying of the titanium make any difference. I would be grateful for any help.

Thank You,

Jim Schweikert
- Las Vegas, Nevada


A. I have experience with anodizing small parts in titanium (commercially pure grade 1 and Ti 6Al 4V) and niobium, but nothing as large as your part. The current densities that I use vary from about 5 amps per square inch to less than an amp per square inch. I suggest that you start out on the lower range to avoid accidentally etching the piece. I use a solution of 3-5% by weight trisodium phosphate [affil. link to info/product on Amazon] in water. Keep the solution below 80 °F. I get more vivid colors on the 6-4 than the cp titanium, probably because it seems to take a higher finish easier. If you do not already have a suitable tank, you might try anodizing the piece with a brush saturated with the solution connected to the positive lead and the piece grounded to complete the circuit. You could use a painter's brush with the metal ferrule wired to the lead and then insulate the handle for safety. Artists use this technique to paint on sheets of Titanium.

Howard Bailey
custom body jewelry - Flagstaff, Arizona


Q. Where can you get an economical anodizing machine?



A. Dan,

I'm afraid we'd need more info to be able to properly answer your question. An anodizing line for an aircraft manufacturer might be $5 million and still be considered a very economical machine whereas some people who want to do anodizing in their basement feel that $59 is too much to pay for the power supply.

To play around and experiment you probably need only a power supply, some stainless steel for an anode, and a plastic vat of some sort.

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Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha

Anodizing or Color Finishing of 6AL-4V Titanium


Q. I am trying to find out any info on anodizing or the finishing of 6AL-4V titanium.I have seen in some posts that anodizing can be done and if so what is the range of colors. The part will be a casting if this helps. Thanks to all that help!

Buck Jones
- Roanoke Virginia USA


A. It takes from 0 - 240 volts to get the variety of colors. Exact voltage control is mandatory to reproduce the same color. It will work on castings, but not quite as well. It is not as bad as aluminum or zinc castings to treat. Going from a hot rinse to a cold rinse a few times before you start will tend to fill the pores with water rather than chemicals, so there will be less bleeding when you finish.

James Watts
- Navarre, Florida


A. You can get a kaleidoscope of colors when anodizing titanium. Solutions of various electrolytes are used: sulfuric acid, phosphoric acid, sodium hydroxide, ... As stated above, the voltage and time applied as well as electrolyte concentration will determine the color produced.

Titanium anodizing is one of those finishing processes that very closely approaches "art"; it takes a lot of leg-work, tank work, trial and error. There are some very good finishing houses that have perfected the process in terms of color matching, etc... Your alloy is a common one and should present no special problem to anodize.

Megan Pellenz
Megan Pellenz
- Syracuse, New York


RFQ: I am looking for a testing laboratory who can perform the wear resistance and propellant compatibility tests on Titanium anodized samples according to AMS 2488 [affil. link to spec at Techstreet]C. Can any one help me out here, please. Thanks

Jonnathon Tan
^- Sorry, this RFQ is outdated
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Q. Need information on the Watervliet Process, chemical composition & other operating parameters.

Jim Chan
- Granger, Indiana


A. Hi Jim. Watervliet Arsenal is a major army installation so they have probably done more than one investigation of titanium anodizing, and I don't know exactly what the Watervliet Process means to you or others, but they did do a pretty exhaustive study of titanium anodizing -->

Luck & Regards,

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Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha

Anodizing of Titanium Difficulties


Q. I am a jewelry manufacturer in Australia and I realize from reading many of your past letters a lot of your members have considerable knowledge in the plating of titanium. We are trying to get consistent results in various colours anodizing wedding rings.

We have a variable 100 volt rectifier x 5 amps which we do not have control over. The solution we are using is 10% water, 10% sulphuric acid and 80% phosphoric acid. The cathode is platinized titanium mesh and the anode (ring)is being connected by 3 mm copper wire.

Unfortunately when we perform the process the amperage increases much quicker than the voltage the maximum voltage I can produce before the D.C overload cuts in is about 20 V, and although we may reach 20 V the anodizing is only a faint yellow. Do we need to be able to adjust our amperage down, is there a particular cathode to anode ratio we should work to. Any assistance helping us to get an accurate and consist setup would be greatly appreciated. Regards A. Jackson

Aaron Jackson
- Australia


A. I doubt if you will ever anodize with that strong of an acid solution. Try using a 7% trisodium phosphate [affil. link to info/product on Amazon] in distilled water and you will have enough amperage to anodize and not exceed the shutdown amperage. This will also allow you to get to your 100 volts. A plus, it is totally non hazardous. Reason, it is less conductive. What you have now is the crude equivalent of a dead short.

James Watts
- Navarre, Florida

Help anodizing titanium tubes?


Q. Hello,

I have a project which requires some knowledge I currently don't have. I hope someone on this list may have had some experience in this field and can shed some light on this sub. for me.

I have a client who needs Grade 9 titanium tubes anodized with a series of numbers on the external surface of the tube. All tubes are dia. 30 mm, wall .9 mm, about 1 meter in length. I've seen titanium products anodized before but never small portions. I would like to know if it is possible to mask off the tube leaving only the numbers exposed and paint apply an acid solution for anodizing? Does the whole tube have to be in the bath to anodize?

I have never anodized metal before and would appreciate any information regarding this question or anodizing titanium in general. I would like to keep the investment to a minimum as I'm not sure if I want to take on this project.

Thanks in advance for the help.

Best regards,

Darren Crisp
titanium fabrication - Houston, Texas


A. Titanium can be anodized according the voltage in sulfuric acid, the same as aluminium , and the colour may go blue to violet to yellow around 40 volts.

Once I used styrofoam in MEK / methyl ethyl ketone to mask and it worked.



Cair Shishani
Khair Shishani
aircraft maintenance - Al Ain, UAE

How to Setup Titanium Anodizing


Q. My company is looking to do it's titanium anodising in-house. I have been tasked with the job of getting our company set up to do so. My problem is that I know little about the needs of this type of operation. So here are my current bank of questions.
1) Is TSP the typical chemical used to anodize titanium?
2) Do I need an adjustable DC power supply?--what voltage range, amps and wattage?

If anyone out there could help me out I would appreciate it.

Michael Kemmerer
medical component manufacturer - Quakertown, Pennsylvania


A. There are two quite different types of titanium anodizing, Michael. There is a decorative anodizing used on jewelry that produces thin refractive films in attractive colors, which is usually done from solutions of mild acid, or TSP [trisodium phosphate [affil. link to info/product on Amazon]]. And there is a heavy anodizing done from an alkaline bath for the purpose of making the surface less susceptible to galling; this is often done to spec AMS 2488 [affil. link to spec at Techstreet].

If you can tell us a bit more about what you want to anodize and why, we can probably help you narrow it down to which type you are looking for.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha


A. Michael,
You'll find many knowledgeable and kind people that take their time answering letters here. But regardless of how much help you may receive through this forum, without previous experience, it'll never be enough to set up a good level industrial operation almost from zero. It may appear very simple but involves years of hands-on and theoretical knowledge. I recommend you to hire a consultant.

Guillermo Marrufo
Monterrey, NL, Mexico


Q. We currently do anodizing, but have not done any titanium anodizing. Can anyone please advise me the makeup of the electrolyte that is referred to in AMS 2488 [affil. link to spec at Techstreet]?

Nathan Layman
- Galland, Texas

A. Hi Nathan. Your question relates to one of those weird situations in the metal finishing world. Nowhere in my library of finishing books is anodizing of titanium mentioned, and AMS2488 doesn't tell you what solution to use or how to do this process; that is a trade secret :-(

Originally Tiodize was the only well known company offering the process, although a number of other shops offer it now, and a few consultants can help you. But successful AMS2488 titanium anodizing involves tricks and solution compositions that are not yet generic knowledge. Sorry, but you have to either farm it out, or retain a consultant who knows how to do it, or do a painstaking gleaning of snippets of info from a computerized literature search and develop it independently.


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Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha

Titanium anodizing contamination problems

October 27, 2018

Q. Hi. I work in the aerospace industry and am having issues with contamination on titanium fasteners; our process is as follows:

1 hot caustic 10% clean
2 water rinse
3 etch tank 60% water 30% nitric 10% HF (parts held in solution until pickling starts then timed)
4 water rinse x2
5 anodise tank 25% sulphuric
6 Water rinse
7 hot DI water seal

Prior to this operation we degrease the parts through our vacuum degreaser using Dowclene and then anodise straight after but we still seem to get what looks like oil stains on the finish parts after anodise ... but not every one, just some random parts. This issue has been going on for a while -- any advice would be helpful. Thanks.

john Mckeown
plating supervisor - Rugby Warwickshire England

October 30, 2018

A. Rinse water cleanliness is my first thought. Are you using tap or DI for rinses? Are your rinses flowing or recirculating, and does the operator spray the parts down as they leave the rinse tanks? What is your limit for rinse cleanliness? Are there potential sources of contamination from either inorganic substances (such as drag-in from prior chemical tanks) or hydrocarbons (such as cutting fluid haze in the air from equipment nearby)?

If airborne hydrocarbon contaminants are an issue, they can also affect chemical tanks. I have personally seen this in desmut and anodize tanks, as our shop shares a building with a large machine shop, and we have to do more frequent tank changes as a result. The presence of scorched-looking, greasy dark brown or black residue at the waterline of your anodize tanks would be one indicator of hydrocarbon contamination.

Rachel Mackintosh
Plating Solutions Control Specialist /
Industrial Waste Water Treatment - Brattleboro, Vermont

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