If it were me, I'd turn it over to a good Corvette or boat repair shop. They can determine the material and make a proper repair.
By the way, is this really your first post or did you re-register on the new forum? If it's the former, welcome to iRV2!
2011 Dodge Ram 3500 Laramie Cummins 6.7L/68RFE 6 speed auto/4.10LS crew cab LB dually
2004 Doubletree Mobile Suites 36RE3 5th wheel
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