Not an endorsement but just some information I bookmarked a while back. This type of product is used daily in the bodyshop world and is an alternative for welding thin metals.You can also search the site for products used for many types of plastic panels.
http://www.lord.com/Home/ProductsServices/Adhesives/FusorAutomotiveAftermarketProducts/Products/MetalAdhesives/tabid/3400/Default.aspx
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http://www.lord.com/Home/ProductsServices/Adhesives/FusorAutomotiveAftermarketProducts/Products/MetalAdhesives/tabid/3400/Default.aspx
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