^ Someone's got attitude, lol
" I paid Aavid $40 for a U shaped piece of magic aluminum"
Seriously, all depends what you are doing, how much you want to spend, how much heat you need to dump and into what kind of environment, how many you're making, and if you need to look like you're irreplaceable to your boss when the layoffs come.
Wll yeah...huh. You can to some extent use scarp plates to make some simple heatsinks that do when you need to dissipate low wattages. And some heat sink is better than none. But if you try to make a more complex heat sink sandwiching plates together and bend them into a heat sink ish shape. You will have the problem that the thermal resistance between each plate will be quite high or worse. And hence it will be bad design idea from the start