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Old 08-01-2011, 02:04 PM
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GearNut GearNut is offline
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Join Date: Aug 2009
Location: San Diego, Kaliforgnia
Posts: 5,106
Default Re: what did you do to your motor bike today?

In reference to Creative Engineering's entry of "DO NOT MIX STAINLESS WITH ALUMINUM...especially cast aluminum where heat is involved. Over time the materials will bond together making removal impossible. Wring them off and drill them much fun!"

Stainless also being a dissimilar metal that aluminum will create a galvanic effect (read battery effect) when in close contact with aluminum. Threaded into a hole of aluminum is a recipe for disaster when heat and moisture are present. The threads will start to corrode in the aluminum as it is a softer metal than stainless thusly weakening them.
The stainless will also pit a little and the resulting oxides that form in between the pitted stainless and corroded aluminum will effectively create a "super loc-tite" effect.

Oil or grease can slow this reaction down a little, but not stop it. The best I know of is simply to use milk of magnesia. That's right, the stuff that is sold in the medecine section for bowl problems. The magnesium will act like a sacrificial metal and stop the corrosion between the stainless and aluminum. The magnesium will break down very slowly. It will not act like a loc-tite. It will not cause the threaded parts to come loose any easier than if assembled dry.

Shake the bottle up very well, pour a little into a cup and dip the threads of the bolt or stud into the milk of magnesia before threading them into the aluminum.
Wipe off any extra that gets squished out.
"It's a chinagirl. It's a sometimes fun little engine that often will break your heart. It's disposable.

Does not come with a fortune cookie."
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