So, to rivet aluminium panels to the steel chassis, should the mandrels of the sealed/closed rivets be:
With rivets as a rule you get what you pay for... A steel/stainless mandril will give greater shear strength. There can be corrosion issues. If you
are not relying on the rivets for structural purposes or bonding as a primary method then aluminium/aluminium should be OK. Any decent rivet will use
7075 grade aluminium for the mandrel and that is pretty tough
Best by far for home use is Cherrymax of equivalent