On its own the hot glue will not provide a very strong hold but used with holes in this manner it creates a mechanical bond strong enough to support the weight of the metal.
Attaching something to sheet of aluminum.
Regardless of type self clinching fasteners install permanently in thin ductile metal sheets by being pressed into place in a properly sized drilled or punched hole and by applying sufficient squeezing force.
All other metals will react with the aluminum causing damage to the siding over time.
They can be used to securely fasten metals together including aluminum.
Measure and mark the length on the drill bit with masking tape.
So whether installing screws into solid laminate or through a fiberglass skin into a core plug of cured epoxy use stainless steel sheet metal screws.
Wrap a piece of masking tape around the drill bit as a guide.
Apply a coat of contact cement to the back of the first aluminum sheet while the adhesive on the wall is still wet.
Lift the sheet to the wall and press it against the drywall aligning at least.
But sheet metal screws should never be used to fasten hardware to extruded aluminum spars masts booms spinnaker poles and so on because sheet metal screws are designed to be held in place by a single thread and are not meant to cut threads they distort the walls of the hole into a helix.
Select the proper drill bit.
With thin lightweight aluminum you can glue the metal using hot glue provided that the metal has a few holes drilled in it through which the melted glue can flow then harden.
When attaching a flag bracket to aluminum siding use only aluminum or nylon brackets.
Use a metal bit to drill holes in the metal.
Folding and adding bending tabs is one of the easiest and most economical way of making moderately strong joints in sheet metal parts that will permanently or semi permanently attach to one.