Anodising FAQ's - Your questions please.

Anodiser Steve

Due to a lot of interest, I am thinking about writing a piece on the anodising process and hopefully answering as many questions as I can that you may have.

Please reply to this topic with any questions you may have or think may be useful for an anodising thread for others to easily find and refer to.

I am also keen to have the moderators let me know what is deemed to be within guidelines for a topic of this nature. As many of you are aware, I did make a very informative posting a while back but it was removed because of it being classed as advertising. I understand that this is a sensitive subject but would like to work with you to provide an informative and comprehensive reference for anybody who is looking to have anything anodised.

Steve Barry

The Northern Monkey

Can you anodize my GF's cat?



Seriously though:

Will the chosen colour be guaranteed to match other parts?
IE, if I got a few bits anodized, will they all be the same or can some parts react differently?

can I choose any colour or are there only certain ones or ones that work best?

how do i know if a part can be anodized if i'm not 100% sure on the metal type? what metals can be anodized

The Northern Monkey

do you do purple?

can 1 part be anodized multiple colours?

weescott

Hi Steve,

you replied to my email last time with some very useful information.

One part of which you stated that anodising Titanium is a bit of a dark art and very temperature dependant. Some elaboration on this would be useful for others.

Anodiser Steve

Good Questions.

Firstly, here is a list of colours that we currently have.

Black
Silver/ Clear/ Natural (All the same thing)
Pewter
Light Blue - Dark Blue
Turquoise
Purple
Red
Lime Green
Dark Green
Yellow
Gold
Orange
Bronze
Pink (Only works on small parts)

I think I have remembered them all but if I think of anymore I will be sure to add them.

Colours can be combined to create shades... the lime green is made by using a mixture of the turquoise and yellow.
Two tone effects are possible on longer or larger items. One end gets submerged in one colour and then the other end in another. The overlap can create some interesting fades and changes in colours. It is possible to get a straight(ish ) line between colour transitions but it is not usually very sucessful.

Different grades of aluminium do anodise differently. This is not always a problem because each grade of material is identified chemicaly before they even go into the anodising vat, jigged seperately and given more or less anodising time to build up the optimum coating thckness.
Because they are jigged up seperately, a very reasonable match can be achieved by simply giving the parts which don't absorb the dye so fast, longer to do so.

Put simply, the only metal that can be anodised is aluminium. Different grades of aluminium all have different chemical compositions. High strength alloys have high copper and magnesium content. Others have more zinc or iron. Essentially, from an anodisings perspective, there are only two grades of aluminium. The pure HE30's and the free machining HE15's.

Some parts may look like aluminium but may be a casting. Castings are rarely any good for anodising because of the high levels of foreign metals used in the mix to help the casting flow and form when it is being poured.

Forgings may look a little like castings but these are stamped out from a solid bit of aluminium so these will work.

Anything that is sheet, billet, tube, bar or extrusion will most certainly anodise ok.

Aluminium is light, non-magnetic and often anodised so can usually be easily distinguished from other metals.

Steve

Anodiser Steve

weescott wrote:

Hi Steve,

you replied to my email last time with some very useful information.

One part of which you stated that anodising Titanium is a bit of a dark art and very temperature dependant. Some elaboration on this would be useful for others.

I believe the anodising of titainium to be a bit of an urban myth as it is a very inert metal. It will not respond in the conventional sense of anodising in that it will not creat an oxide layer to be dyed like aluminium will.
The only way I have seen to create colours in titainium is to use heat.. lots of it.

Steve

Anonymous

I thought Titanium naturally oxidises, and that the oxide layer prevents any further deterioration?
I also believe it is highly thermally reactive. Bit of an odd one.

I can't remember though, it's been ages since I studied this stuff, and we barely touched on Ti anyway.

(not that this has anything to do with anodizing, I'm just musing out loud)

Anodiser Steve

yeehaamcgee wrote:

I thought Titanium naturally oxidises, and that the oxide layer prevents any further deterioration?
I also believe it is highly thermally reactive. Bit of an odd one.

I can't remember though, it's been ages since I studied this stuff, and we barely touched on Ti anyway.

Aluminium naturally oxidises.. an old piece of aluminium left outside all year will actually absorb a small amount of dye. Anodising is the process which controls this oxide layer to build it up to an optimum thickness.
Irons oxide layer is in the form of rust.
I've no idea what titainium's is but whatever it is, it isn't very porous.

Some of our jigs are made from titainium and when they come out of the anodising vat, the are all the same colour, suggesting that is is something to do with the voltage and temperture combination. It's not something we have really ever looked in to though I'm afraid.

Steve

The Northern Monkey

are there any colours that are more expensive?

any tips to get the current paint off parts and the finish required or is it something you can do?

Do you do any prep to the metal to ensure a good finish or does it depend on the condition you receive the parts?

tri-sexual

titanium dont oxidize
its one of the reasons why it is used for medical applications where chemical changes can cause reactions inside the human body and cause the body to reject the foreign object.
titanium is acid, salt and chemical resistant, one of the reasons why it can stay looking like new without paint or other protection for years and years.

Anonymous

So, what do you think Titanium oxide is? They use it to make white paint.

Anodiser Steve

The Northern Monkey wrote:

are there any colours that are more expensive?

any tips to get the current paint off parts and the finish required or is it something you can do?

Do you do any prep to the metal to ensure a good finish or does it depend on the condition you receive the parts?

Any single colour costs the same. Two tone and fade effects cost a bit more.

we don't do painting and therefore have no means of removing paint despite having chemicals which can dissolve metal and my clothes.
Your best bet is to ask a paint shop if they can strip paint from your parts or have a go yourself with Nitromoors paint and varnish remover.

The finshed anodised result is directly related to the surface preperation. Basically, the shinier the aluminium is to start with, the glossier the color at the finish.
Scratches in the bare aluminium will still be there after anodising but all the same colour. If ou require a perfect finish then scratches need to be polished out. Light scratches can be concealed by bead blasting but it depends if this is a finish you require as it adds texture to the component which may not be what you are after.

Steve

pastey_boy

http://www.titaniumarts.com/pages/bikea ... ?content=3

The Northern Monkey

Anodiser Steve
Brilliant answers cheers Steve!

tri-sexual

yeehaamcgee wrote:

So, what do you think Titanium oxide is? They use it to make white paint.

i think you are mistaking titanium alloy with titanium ore.

Anonymous

I might be, but I don't think so.

supersonic

The reason why titanium is so resistant is its oxide coating. TiO2 is widely used in industry.

apriliarider

I have an Intense 5.5 - would it be possible to get an anodised coating as durable as the finish on the Yeti 575 - would not be bothered if matt or shiny finish??

I would think that the bottle cage holders would be a problem (steel inserts) - what would be the best thing to do with these (I never use them) ???

Cheers

Martin

NatoED

dear steve how much would it cost to do a frame and what prep work would i need to do to get it ready for you?

Rindle

If I have something which is already anodised is it possible to remove the anodising to get it done in a different colour?

ride_whenever

Steve, if you could easily manufacture a highly porous titanium oxide layer would that then take the dye better? There must be a relatively easy way to make nano-porous titianium oxide on the surface as it's fairly well explored chemistry.

djcombes

Titanium does oxidise very readily in air. As someone has already pointed out, titanium forms a native oxide in contact with air or water, the growth of which self limits to around 25nm. A quick look on wikipedia shows that anodisation processes for titanium do exist, but that the layer thickness is limited to sub micron (wiki cites a limit of 300nm, but doesn't specify what factor limits growth.

AMS 2487 and AMS 2488 are cited as titanium anodisation standards.

The wiki page appears to be lifted directly from http://anodicprocesstech.net/titanium_anodizing.html

Where several pictures of anodised titanium parts are shown.



The colours resulting from this process are the result of the optical properties of the thin film, rather than the addition of a dye. I'd speculate that perhaps the films are less porous than those resulting from typical Al anodisation processes.

myopic

Good idea for a thread - I had been thinking about anodised frames vs paint/lacquer.

How robust is an anodised frame finsh compared to paint and lacquer? I know it won't chip off, but will it eventually rub through on repeated contact areas more than paint would? if the answer is yes, are any colours more resistant to this?

thecremeegg

Ah I was considering getting my frame anodised due to the fact the original colour is wearing away. How much does a complete frame in general cost to anodise or would an answer be classed as advertisng?

ssjambro

Can steel be anodised?