Steve,
The problem is recutting chips, the less flutes the better as it's not the cutting action that's the problem, it's the space for the chips to go.
A single flute router cutter works best in alloy unless you buy special cutters.

Even then you need coolant, well more lubricant to be precise to stop the welding to the tool.

WD40 is advise for aleoy and it works well but being tight I make my own, 75% paraffin and 25% ATF or any light hydraulic oil.

Modify an oild spray gun to give you plenty of air but just a dribble of knacker laqueur.

.