This is what i will more then likely be using...
3M Automix Truck Line SMC/Fiberglass Repair Adhesive
<TABLE cellSpacing=0 cellPadding=0 width=555 border=0><TBODY><TR vAlign=top align=left><TD style="PADDING-TOP: 10px" width=81><CENTER>
- </CENTER><!--Main Picture End--></TD><!--Spacer Column Start--><TD>
</TD><!--Spacer Column End--><TD style="PADDING-TOP: 5px"><!--Short Description Start--><SHORTDESCRIPTION>Two-part epoxy used to bond Steel, Aluminum, SMC and FRP (traditional fiberglass) body panels to each other and to metal frames (no primer required). 90 minute worktime, 4 hour clamp time, and 24 hour cure time.
</SHORTDESCRIPTION><!--Short Description End-->
</TD><TD vAlign=top align=right></TD><TR></TR></TBODY></TABLE><TABLE><TBODY><TR><TD></TD></TR></TBODY></TABLE><!--Product End--><!--Begin Marketing Block Template--><!--no content for marketing block--><!--End Marketing Block Template--><TABLE cellSpacing=0 cellPadding=0 width=555><TBODY><TR><TD>Additional Information
</TD></TR><TR><TD><!--Begin Long Description-->Automatic mixing with excellent sag resistance. Longest work time for bonding large areas, i.e. hoods and roofs caps.
</TD></TR></TBODY></TABLE>
Heres the link to 3Ms product page:
LINK
Follow that up with a few rivets and youll be all set.
Let me know if you have anymore questions.
Corwin