Cutting ACM 3mm (Aluminum Composite Material) Manually?

[player]

I have a 4' x 8' print mounted on 3mm ACM and I need to cut 3/8" off the 8' length. I want to use some kind of a hand tool. I was thinking about scoring it with a box cutter, then using a plastic scribe cutter to get through the plastic. With the cutoff being so small it will be hard to snap it unless I get a good part of it cut.

Any suggestion please?

Thanks.

 

[Zx360]

We use a sharp blade in a box cutter, it will cut the aluminum and plastic. It just takes a real passes. You do tend to get a nasty edge, I grind that down with a file

 

[TonyC]

Score one side with 2-3 passes. Flip the panel and make 3-4 passes. Change the blade between sides. You can fiinih the cut by snapping off or 2-3 more passes with another new blade will finish the cut.

 

[player]

Thanks. I used one of these:

 

[shoresigns]

Box cutter will work, but a scoring knife is the right tool for this.