For those cases try a set of metal shears which create a small slot in the metal removing a thin center piece while leaving the metal sheet flat.
How to cut thin aluminum sheet.
Most tin snip manufacturers color code their.
Mark the start and stopping point of your cut with a grease pencil or some similar implement that marks on sheet metal.
Align the tin snips with the sheet metal.
Cutting aluminum sheet metal with a hammer and chisel is relatively straight forward line up the edge of the chisel along the line you wish to cut and strike the chisel with a hammer.
Choose between red blue or yellow snips based on the cut direction.
Clamp the sheet metal in place on your work table to hold it in place while.
If you use metal shears to cut thin sheet metal such as duct metal it curls and can be difficult to flaten properly.
Set the piece of aluminum on a table or over sawhorses and position it so the cutting area has open space underneath it.
The illustrations are for a small bracket but i have cut 3 foot long pieces using this method.
Make your first cut.
Using tin snips for thin sheets 1.
Using a softer piece of material such as wood as a backer will allow the chisel to push through the metal and prevent wear on the chisel s tip.
How to cut fold sheet aluminium.
Clamp the aluminum down.
Sheet aluminium can be cut without the need for a guillotine or tin snips which tend to deform the metal.
These photo steps show that it can be done using a utility knife.