Bright anodizing 6061 Aluminum

"The Surface
Treatment &
Finishing of
Aluminium and
Its Alloys"
by Wernick, Pinner
& Sheasby

(note: this book is two volumes)

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A. Hi Paul. I have no idea where 'IVOR' is; I assume it is a typo or spell check error -- but let us know.

Our "Introduction to Anodizing" FAQ should get you started at least, but one of my anodizing books is 1,264 pages -- so please recognize that unless you tell us pretty explicitly who you are, what you do, exactly what it is that you want to anodize, and why you want to anodize it, it's honestly pretty difficult for people to help by summarizing what is important to you.

Luck & Regards,

A. Hi John. Mechanical polishing may be the best way for your furniture. But if you are looking for the bright look you'd get on a reflector for outdoor lighting, or a doctor/dentist light, or aluminum hubcap, this is achieved by bright dipping in a nasty nitric-phosphoric acid mix before anodizing (the process is readily automated though). 6061 is not the best alloy for full specular brightness.

A. The process for bright dipping aluminum involves at least 4-5 additional tanks and is operated at 210 °F. It typically is a phosphoric-nitric acid solution which evolves nitric acid fumes as well as NOx. Also, as a first step, 6061 etches well but is not the best bright dip alloy in the extrusion business; 6463 is the best but 6063 is better than 6061. If you are not prepared to tackle this you may want to find a jobshob that will.

A. Hi Kenrith
Actually 6061 is relatively easy to anodize. What alloys are you processing that you find it easy to anodize? And what problems are you having with the 6061? Are you bright dipping and what chemical are you presently using if you are?

A. The devil is in the details. And that's what is needed here, more details. Try answering the following questions. Can I produce good anodizing on other alloys? Have I produce good anodizing on this part ever? Is my anodizing line thrown together or is it designed from the start to produce good anodizing? In most canes if the line is set up correctly with reasonable controls and kept in line chemically, 6061 should be cake walk (easy). Be honest and look at what you are doing; evaluate these parameters and give us more details.

A. 6061 T6 alloy is the most popular Al alloy in China for anodizing aluminum. It is a very suitable alloy for chemical brightening. Most job shops should have no problem to give you good results.

A. Ensure thru certs or chem. testing that you are indeed using 6061. A problem we have once in a while is releasing a dwg. to a machine shop calling for 6061 plate with a tight flatness tolerance. The machine shops will sometimes use jig plate, it is harder and does not anodize well at all. The color of black anodizing comes out much lighter and is easily identifiable.

A. Hi Sharon. As you already know, color and texture matching anodized aluminum is not easy. But electropolishing can certainly deliver the brightness of chemical polishing and more. The finest aluminum telescope mirrors are electropolished rather than bright dipped.

Regards,

A. Two possibilities: (1) Since you say "a", it seems the case is about 2 pieces, one in 6061, the other in 6063. Apparently there was a partial electrical contact failure on the 6061. OR (2) If the sand blast media had been used on any other metal, then you have embedded foreign metal in the soft aluminum, then if the "chemical polish", what ever that is, did not go deep under the embedment, you have the "dusty" residue.