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      07-15-2010, 10:57 PM   #9
GregW / Oregon
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Drives: 2023 M2 Coupe, 2020 GLE 450
Join Date: Nov 2005
Location: Lake Oswego, OR

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Dissimilar metals and corrosion

Quote:
Originally Posted by elp_jc View Post
I asked our friend SOCAL if we could use aluminum, since the rivets' only job is to hold tips in place (zero shear force, etc), but he never replied. Maybe somebody else can answer that. I want to remove the tips before powdercoating my muffler for extra safety, but not if it costs $60.
Stainless is the correct rivet material for stainless, as any dissimilar metals have some galvanic reaction (meaning they corrode with exposure to moisture) over time. For "harsh environments" subject to moisture there should be no more than 0.15 difference between the metals' anodic index (see following chart). For stainlesss and aluminum it is aobut 0.25 - 0.40, depending on the aluminum composition. In the real world, for this non-critical installation, it's not a big deal, but I would probably still pay a few bucks more and get the sst myself. The other option is to go with a factory painted rivet which prevents the metals from coming in direct contact (I know you can buy white ones).
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Greg Lake Oswego, Oregon, USA
2023 M2 Coupe - Brooklyn Grey/Cognac/CF, 6MT; 2020 MB GLE 450

Last edited by GregW / Oregon; 07-16-2010 at 08:26 AM..
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