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Grain refining etch on aluminum

 

I need an effective method of etching 6061 aluminum to produce a dull matte finish without exposing the pronounced large grain structure. I currently use a caustic etch. I have tried lowering the bath temperature and one proprietary grain refining additive without the desired results. I will subsequently black anodize the part.

Stuart Price
- Dayton, Ohio

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You can vary the caustic, carbonate, and simple and complex phosphates to vary the etch.

Then you can try acid etchants containing fluorides will produce a satin etch on some alloys.

Perhaps even a chemical polishing solution may change the look of the surface. One based on phosphoric acid, nitric, acetic, etc.

Best wishes,

  
Tom Pullizzi
Falls Township, Pennsylvania