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Re-anodising aluminium

2006

I have some parts made from 6082 aluminium which have been clear anodised.
These then get laser marked, basically removing the layer of anodising, taking me back down to the raw material.
If I re-anodise these parts, and dye them black, will it affect the anodising that is already there? Or will I just be left with the original clear anodising, and black anodising on the areas I had laser marked?

Regards,

John Peacey
Production engineer - Gloucester, UK

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2006

Hello John,
First, it is not necessary for the laser engraving to be completely through the anodic coating.
Second, in order to re-anodize a part must first be stripped of the previous coating.
What are you tring to achieve?

Bill Grayson
metal finishing - San Jose, California, USA

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First of two simultaneous responses --

Practically speaking Bill Grayson is absolutely correct.

Theoretically, if the original seal was 100% perfact, and if you can find a bare contact point, you can put it back in and "re-anodize".

Sealed soft coat is a well known maskant for hard coat, but most shops do not control their seal and never get a perfect seal.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2006

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Second of two simultaneous responses --

Hi Bill,

I'm just trying to achieve a clearer laser mark.
At present it comes out whitish, which doesn't stand out too well against the clear anodising.
I'm not sure if there is some other way of dying the areas that have been lasered, but if you know of any, please let me know.

Cheers,

John Peacey
- Gloucester, UK
2006

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2006

Hello again,
I have extremely little knowledge of laser engraving. My customers' do have their parts engraved, and I believe I have seen black, laser engraved lettering on anodized parts. How they are done I have no clue, laser engraving is a different sport.

Sorry I can't help you there, Bill.

Bill Grayson
metal finishing - San Jose, California, USA

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2006

I must affirm what BoB said with the seal.. If you sealed the part correctly, skip the etch and try to plate it. Otherwise you could used a Ultra fine tip marker to "pocket anodize" the part (lol)

I am really at a loss for this question, I am interested in the answer..

Ryan Cook
Toccoa, Georgia

We are also a manufacturer for aluminum products. And some of our products also need to be made a laser-engraved logo after anodizing or coloring. Our laser-engraved logo maker can make a laser-engraved logo to be black us by putting some aquaform chemicals(clear like water) on it. Hope it is helpful for you

Winson Wen
- Shunde, Guangdong, China
2006

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2006

Just tried double anodising some parts, with kind of encouraging results.
The areas I laser engraved came out nice and black, but the rest of the part acquired a grey-ish tinge.
Probably because it wasn't sealed well enough.
I'll keep trying though!

John Peacey
- Gloucester, UK