/diy/ - Do It Yourself

i want to make channel milled balisong handles out of solid copper ive melted from scrap. obviously copper is very soft so i would like to work harden it so it doesnt just bend and deform. i would take the copper slugs i have and cast them into a square bar that i would then mill. would it be easier to go about this before or after milling it out? how would i go about it?
>youre not allowed to make weapons here
i just want handles.