Step 1: Requirements
sharp hobby knife & blades
sandpaper, dremel/drill various tools,
small pieces of sheet metal
wood - i had some stuff that was 42mm wide and about that was perfect.
L shaped brackets and various screws, washers and bolts
sheet foam - the stuff that aircraft modellers - balsa wood or stiff cardboard at a pinch
various glues - foam glue, superglue, epoxy
brass or aluminium tubes of varying sizes - 2.5cm aluminium tube x 70cm or so
water putty and black acrylic paint or ink
vaseline or oil to use as a release agent
air drying hobby clay / fimo
lead fishing weights or scrap small pieces of metal.