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Water meter mfgr needs durable and safe aluminum finish

Hi,

I am a design engineer for a UK based company that designs and manufacturers water meters.

I am looking for information about corrosion resistant finishes applied to Aluminium alloys that are used in the food industry.

I have a project where I am considering using AL (LM25TF) for the main body casting of a water meter, this will require some form of corrosion protection. As this meter could be used in drinking water supply a finish is required that is safe for the water to come into contact with, the food industry being the most obvious application.

If anyone could provide any information about recommended processes/grade of finish I would be most grateful.

Many thanks,

Nick Rollings
Water meter design and manufacture - Luton, Bedfordshire, England
2003

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Hard Anodize Per MIL-A-8625 / MIL-PRF-8625 [on DLA] Type III class I with a DI-Seal is a possibility. As far as I know the process is accepted as a "food grade" coating and should offer quite good corrosion resistance as long as the pH stays fairly neutral.

Bill Grayson
metal finishing - Santa Cruz, California
2003

High Phosphorous Electroless Nickel, food grade approved (no lead or other heavy metal traces). Extremely durable for aluminum in contact with drinking water.

Guillermo Marrufo
Monterrey, NL, Mexico
2003