Not too long at all. Once you get a decent technique down, it's pretty easy going.
Today while I was at work (metal recycling yard), I came across a couple more things I'll be able to use in the new computer.
Some aluminum mesh for fan grills.
And I came across this as I was unloading a truck. I figure I can try it out and see how it works as the radiator for the liquid cooling kit I'll be putting in.
It all cost me only $2, so I figured why not.