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 [on eBay or Amazon] 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 [on 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. One possibility: Occasionally, some pieces in a rack get loose contact and have to be reworked. When this happens, the resulting finish is more matte.

A. Please bear in mind alloy 6061 always gives matte finish to anodizing process. This is mainly due to high silicon content in the alloy. To my opinion, there are no alternative ways to prevent matte anodizing finish if using aluminium alloy 6061. You can try to use alloy 6063 for testing. For your information, the alloy plays an important role in finishing.

Hope this can help you.

A. Perhaps the success of your finish lies in the tumbled surface. We find it difficult to get consistent results with a tumbled surface because the tumbling is not always consistent. Sometimes we have experienced impinged contamination, such as previous corrosion, on the surface. This causes blotchy inconsistent anodized finishes. Also, the other respondent said it right. There is no way back to the original finish on a rework.

Hope this helps?

A. In order to have a bright finish after anodizing you should polish the aluminium before anodizing. You can try mechanical polishing with a suitable polish paste and cotton buffs. The surface should be very smooth and shiny. Then you can apply anodizing and coloring in black either by dying or electro-coluring.

A. 6061, 6063, and any alloy other than 6463 will not give you consistently what you want.

Those alloys contain high iron in aluminum formulation which adds alloy strength properties but inhibits best bright finish properties.

Second if you are paying for bright dipping from an anodizer that mixes both alloys in the same tank then iron concentration is being built up in the bright dip bath and dulling occurs and becomes erratic.

Guessing you probably need the strength and will not get what you want from 6463 then I would switch to powder coating high gloss no problems.

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. Hi Jon. Although I am not personally familiar with post-anodizing operations to improve glossiness, Willie Alexander tells us above that it can be done by polishing with rouge. He does, however, suggest that you start with a specular finish before anodize.

Regards,

A. I would look at a pre-anodizing brightening either by electropolish or bright dipping. My preferred method would be a nitric-phosphoric bright dip.

A. As per me we can't etch Aluminium after anodizing. If you want to add gloss you can again polish it with cotton woven wheels using lustre powder. It's a simple process and been done widely. It increases the gloss.

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