BAD IDEA.

Aluminium needs to be heat treated after welding. mig, tig, whichever.

There is such a small structural area affected by the dropout joint, all focused one the rider's weight.
Unless you have this done by an aluminium frame builder, who does it properly, it *will* fail. Everyone else who tries will just hack away at it and hope it doesn't break.

my 2 cents- get an ENO or another frame.