Metal finishing Q&As since 1989

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Seeking a method for removal of white rust in Aluminum Casting

We use LM 27 ( Aluminum Alloy) for a component called Housing. The component is a Gravity Cast one. Some times after machining and final washing , if the component is stored for a day or Two, white rust forms on the surface of the component.We do not have a procedure to remove the white rust. Can you suggest a medium to remove the white rust? The component is not painted or plated . It is used as such in assembly .(We use Techniclean SF- supplied by Castrol- as a washing medium.)

Venkateswaran Sridhar
- Chennai, Tamil Nadu, India
2004

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Dear Mr Shridhar,

You may want to use a water soluble wax coating soon after final manufacture that will keep white away for a decent period of time.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2004

Applying wax is the preventive method to predict white rust.,If white rust arised in the component,how to remove it?

Manigandarajan
Manufacturing - Chennai, TamilNadu, India
2006

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Hi, Manigandarajan. If the components are small fasteners, mass methods might work; if sheets or plates, the methods would be different. If they are aerospace parts, it might be illegal to even try. Is this work-in-process in a factory, or are you talking about architectural items which must be repaired in the field? Please tell us some details of your situation. Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

I think, you should check the white rust if it is really white rust or the deposit from the cleaner. You check the rust for it's boron content from any recognised lab. You will get the answer.

Prashant
- Silvassa
2007

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After machining the components are dipped in pure parafinnic solvent for 3-5 seconds which will avoid the white rust formation.

If already white rust is there ...wipe out with fine zero emery and dip in the solvent to avoid further formation

A. Jothimani
- Chennai, India
April 12, 2011