For two pieces like that, use double sided tape.
I use my glue gun for all sorts of things. Turning is one, making templates, holding small pieces to larger pieces for bandsawing, attaching a large twisted or warped board to chipboard to use safely on table saw, or to saw a very thin piece I can't get push stick on, glue a board to flat board and run through thicknesser to get one flat side initially, levelling saw horses, butting smaller boards onto larger ones for track sawing or edge banding, holding things in place whilst making jigs or glue ups... many uses!