Problems achieving shiny/glossy anodized parts

A. Hi michael.

Your problem is the alloy. I don't know anything about 6261, but 6082 (too much alloying elements) is a poor anodizing alloy. It's a construction alloy and are not meant to be anodized except for surface protection. My advise for you is to use 6060, or way better, 6463. These alloys are designed to be anodised and give a good looking surface. 6463 (low copper and fe content) are also meant to be bright dipped in a mixture of phosphoric and nitric acid to get a very high brightness. A problem for you might be the coating thickness, 10um is recommended for bight anodizing.

A. Hi again michael!

Okay, there might be other ways to do this.

This method is used on 6063 and 6005 on one anodizing line. It is used to produce a glossy gold surface:

Polish as usual, remove grease then,..

1. 30 min desmutter.

2. 5 min hot rinse(the first rinse after etching)

3. rinse

4. 30 min degreasing

5. rinse

6. 5 min desmutter

I haven't tried this method myself but I'm told this maintains the polished glossy surface.

One other way is to polish and the use a degreasing which removes the polishing compound and brightens the part. I have heard of degreasing chemicals with does this but I haven't tried them. However etching ruins you polished surface, stay away from it as and you will probably get better results. Etching is not important when you have polished aluminum, just make sure to have a clean surface when anodizing.

A. Michael, I too am a fly reel manufacturer. Most all reels here in the US are made from 6061. We buff our reels to a mirror finish with absolutely no blemishes or buff marks. Each is then cleaned with alcohol and then acetone Acetone [affil link] and are handled with surgical gloves so there are no fingerprints. Each part is then wrapped in the softest paper towels we could find. The anodize shop MUST NOT ETCH the parts. They can not sit on the racks in the atmosphere in the shop either. Minute particles that float in the air will settle on the topside of the parts and can cause a discoloration. Type 3 anodize will produce a slightly duller finish with a slight orange peel effect while type 2 will produce a mirror finish although not as durable. Buffing after type 3 will make a better looking part but may remove the "seal" and you may get some fading of the color. If you have ever seen the Odyssey Reels sold by Orvis, those are mine.

A. Hi Michael. "Type 2" and "Type 3" are references to MIL-A-8625 / MIL-PRF-8625 [affil link or DLA] where Type 2 describes conventional sulfuric acid anodizing and Type 3 refers to "hardcoat" anodizing, which is done at approximately freezing temperature and higher current density, and produces an anodizing thickness of about 0.002". Please see the linked MIL spec or our FAQ "Introduction to Anodizing" .

Regards,

A. Michael,
We have done thousands of "High End" Abel reels. Richard of CTC has a good handle on this, but failed to mention that a lower voltage than normal is required. We use about 13 volts and extend the time of processing accordingly. All that special handling is "reel" important for a top quality product.

A. Most Fishing reels that look really nice gold are BRITE DIPPED before. That is a process you may not want to install = NASTY.

A. Hi Ploen. Although 6061 is not ideal for a bright finish, and people have suggested switching to type 6463, that may not be practical or strictly necessary.

We appended your question to a previous thread on the subject, and I think the first step is buffing it to a shine before anodizing, then carefully taking the suggestions listed above -- which have been offered by people who are very experienced and accomplished in what you are trying to do. Best of luck.

Regards,

A. Dear,
In my experience 6061 T-6 material needs high concentration of Pigment (dye) to get good color, and thickness must be good enough. If thickness is low, color absorption would be less (light color); moreover, parts with polishing & blasting need different time period to get desired anodizing thickness than without polishing and blasting.

A. In my opinion, this is not a dyeing issue. It's a substrate issue, especially if all other parts are fine.

What I can't tell you is the cause of the problem, but if it were me, I'd look pretty hard at your blasting set-up, or the machining set-up. Something prior to anodizing. Figure out at what point prior to masking that the part sits on something that matches the circle you are seeing on the backside.

Look at that operation, and everything afterwards prior to anodizing. As you said, the circle is too perfect. It doesn't appear you are doing any type of etch prior to anodizing, which may have helped this issue.

A. Hi Denvor, We appended your inquiry to a long-running thread addressing this issue. To summarize the things that can help: other alloys may be better, polishing rather than tumbling will increase brightness, careful handling matters, lower voltage may help, limiting the anodizing thickness will help, additional polishing after anodizing is possible,

But please clarify what you mean by "a brightener tank set up". Are you talking about an actual 210 °C nitric-phosphoric chemical polishing installation or something else? Luck & Regards,


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