Quote Originally Posted by jakester
Looking good. Now ditch the foil and paint it flat white in there for some real reflection/diffusion.
This is wrong. Leave the foil in. If white was really such a good reflector, you'd see that in EVERY high-bay HID or T5 reflector.

Metal reflects better no matter what. If you properly applied it, you'll have no heat worries. Also, you don't want diffusion, that reduces photon flux density and thus reduces the effectiveness of the light source. You want pure hard simple reflection.

See my PC case for a proper example. Link in my sig.