View Full Version : Anodizing?

04-22-2005, 12:12 PM
I have some parts to anodize. I have read about hard(wear) anodizing, what's the difference between "normal anodizing" and "hard(wear) anodizing? Is it the same as "Hart Coat" (registred TM)?

What is chemical polishing? Can it be done on 6082 aluminium and how?
If chemical polishing is not an option does it help to polish/buff components prior to anodizing?

I ask all these weird questions, because i'm looking for a bright polished surface finish after anodizing. It's for fly reels....


04-22-2005, 01:05 PM
Anodizing is a surface coating. It will "harden" the surface of the material and also add to the surface (typ. .001 to .0005). When you get your parts anidized any surface marks will be pronounced so if your looking for attractive parts you will need to take much care to prepare the parts. Tumbling is the prefered method, although you can had polish on a wheel if you have no inside corners. Again, tumbling will be done in 2 or 3 different medium and take the better part of a day to complete. The parts will "wear" far better than the raw aluminum (and yes 6061 is a prefered aluminum for anodizing). They have some Teflon impregnation coatings (Nituff) and is comperable in price to standard anodizing in cost, but will wear out steel or stainless in a contact situation. You will most likely pay by the batch and not the parts since they will do it in one run (typically in the states $60 -85 per batch). Good luck man, hope this helped.

04-22-2005, 02:16 PM
You will most likely pay by the batch and not the parts since they will do it in one run (typically in the states $60 -85 per batch).
Deluxe Anodizing
(716) 856-6203
588 Michigan Ave
Buffalo, NY 14203

These guys are local to me, not sure how they work on out-of-state. But, if I remember right they were $40 a batch for small parts (like 100 parts or so). :cheers:
EDIT: I see you are in South Africa - guess these guys probably wouldn't be too much help. (chair)

04-22-2005, 05:14 PM
Regular anodizing is more of a decorative finish. I don't think that its actually a coating, but a controlled oxidation of the aluminum.
Here's a link for home anodizing and general information.

Hard anodizing puts a thin tool steel like surface on the aluminum.


I don't know anything about chemical polishing.

04-22-2005, 06:30 PM
Hard anodizing/hard coat is a controlled process which you will not be able to perform at home.
Normal anodizing is just controlled ozidation of aluminum and does nothing for the hardness of the aluminum. If you are looking for protecting the aluminum for wear then use the hard coat anodization process. Pay someone to perform the job.
Normal anodizing can be done to make parts look nice if colors are needed. This will do nothing for the hardness, just keep it from oxidizing more. A nick or scratch will break through the anodization and reveal the bare aluminum again.


04-22-2005, 11:28 PM
They put that yellow titanium coating on end mills all the time...

What about that? I saw it done once from a distance.. It looked like a big stainless steel pressure vessle with windows in the side. Gotta believe its a cheap process if they use it on end mills.. Its also bright and shiny and very hard...


04-23-2005, 03:58 AM
Thanx for the info guys! JavaDog, here in South Africa i battle to get decent good quality anodizing done. It sometimes frustrates the holyness out of holywater in this part of the neighbourhood when you can't get decent quality work done....

I'll keep you guys posted....

04-23-2005, 04:04 AM
Buscht, i e-mailed Ron for info. Thanx for the link you supplied.

04-23-2005, 06:46 AM

04-24-2005, 05:41 PM
Anodizing is a controlled formation of aluminum oxide, which is formed by converting the aluminum surface. It is done in an electrolyte bath, usually a diluted sulfuric acid at roughly room temperature. Positive DC current is applied to the part, and negative to cathodes, and a controlled amount of current is applied for a given time.

The distinction between common decorative anodizing and “hard” anodizing is a bit subjective. Decorative (type II) anodizing is usually between .0002” and .001” thick, and is in general more porous than hard anodizing (type III). The porosity allows for the absorption of dye, which is then sealed by boiling hot water, often with additives.

Hard anodizing is done in the same way, but at higher current densities and in much colder electrolyte, and the electrolyte may be a different concentration. This forms a thicker coating, and the cooler electrolyte retards the dissolution of the anodized surface by the acid. Thus, the final hard anodize is the same material as decorative anodizing, but thicker and less porous. The actually material is the same hardness, but the “hard” anodizing is tougher due to being thicker and less porous.

While type II anodizing can be easily dyed virtually any shade of color except white, type III anodizing is naturally more darkly tinted once anodized and harder to dye. Black, green, and other dark colors are common with hard anodize. The anodizing and dying are separate processes in this type of anodizing.

There is a chemical dip process called bright dip, which is often done prior to type II anodizing. This is one effective method of brightening parts, and is done in many commercial applications. Many anodizers can do this. For the application of anodized fishing reels with a polished appearance, this is likely the process you want.

Here is a link where you might find some additional information:


Although it more of a do it yourself forum, it may help you to understand anodizing better which might help you even if you send it out to commercial anodizer.

04-24-2005, 10:10 PM
when you andozie remember you have to make threads and any internal or external areas you do'nt want to coat

04-27-2005, 04:48 AM
Did my homework, i found a guy that can do hard anodizing. Going to pay him a visit to dicuss my needs....
Thanx again for all your inputs!

04-27-2005, 04:27 PM
This may be a foolish question (not the first I’ve asked in my life)…

What metals can be anodized?

04-27-2005, 04:43 PM
Aluminum and Titanium alloys.

05-03-2005, 12:07 AM
All of our parts get annodized, type II with R-5 brite dip. We use 6061 and 7075
If your annodizer is good, they will be able to hold .0002. They have no problem maintaining a 1" bearing bore +- .0004, and all sort of threaded holes, usually m6 and m8.

If your after a super-polished finish, you might want to think about polishing alone. Can be prone to corrosion, however is a much more resistant to attack than regular machined un-annodized al. Anodizing will invariably "un-polish" a highly polished surface, although a brite dip with good coloring will still yield a great looking part, IMHO.

05-03-2005, 01:29 PM
I am starting an anodizing business. Will open the doors very soon.

pm me up if interested

05-03-2005, 01:46 PM
I am starting an anodizing business. Will open the doors very soon.

pm me up if interested

Where in the US are you?