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  for Metal Finishing since 1989
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Surface Finishing of Zinc die Castings

I would like some information about surface finishing of zinc die castings.I need to obtain a corrosion resistance of at least 240 hours in saline test (spray of NaCl and water). I will consider any method, galvanic or not, able to produce this result. At the moment I am waiting for some samples coated with "finigard".What is the best treatment in absolute, and what is the cheapest to obtain good corrosion resistance (240 hours test NaCl)?

Thank you very much for your answer.

RUSINA GIOVANNI
- Italy
1996

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Probably the best corrosion resistance is achieved by anodizing the zinc diecastings; salt spray ratings run into the thousands and tens of thousands of hours. Such a finish has been used on the agitator and other internal parts of washing machines. However, finding a shop capable of doing this isn't easy since the required voltages are very high. I believe that Allied-Kelite offers this process and may be able to point you to a shop that does it.

Perhaps the least expensive finish would be a yellow or olive drab chromate.
In between would be the organic coatings. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1996

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Hi,

I have some info on the DELTA-MKS system which basically is a base coat consisting of Zn and Al-particles in an inorganic binder and an organic topcoat. they claim more than 1000 hours in salt spray test, DIN 50021.

Hannes Medelius
- Stockholm, Sweden
1997

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Yes, zinc-rich dip spin coatings like that are another possibility. Thanks, Hannes! But there are probably dozens of possible technologies and hundreds of brand names if Rusina doesn't give us some additional requirements beyond corrosion resistance.

The International Zinc Association (IZA) tested a number of different technologies for coating zinc diecastings, and one of the most reliable for corrosion resistance was electrocoating.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Dear,

Would it be possible tell me anything about "finigard"? Which company provides this coating in Europe and it is possible to obtain any book covering this technology ?

Best regards,

Bervid Zdenek
- Czech Republic
2001

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"FiniGard" is a topcoat applied on top of chromate conversion coatings on metal, Bervid. It appears to be a trademark of Coventya, SA.

There is also an antimicrobial process for wood, called "FiniGuard" -- I don't know exactly what you are looking for, but this is not what our other readers had in mind. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 21, 2008