Quote Originally Posted by Bernice Loui View Post
Cost to water jet cut FR4 or aluminum is about the same. Since the FR4 is coated, finishing cost would be very similar. Very possible raw material cost would be more for the FR4 as non-copper plated FR4 is not a standard item.
Says who? Grainger and McMaster-Carr both sell GR10-FR4, uncoated, for about $10.70/sq ft. for roughly the same thickness as a lensboard.

Their aluminum prices are twice that for the same thickness in aluminum sheet, and around $15 /sq. ft. for aluminum plate.

That's all retail-- I assume bulk/wholesale purchase would be cheaper, but I would also expect the relative pricing to be about the same.

If I were Max, I think I'd feel somewhat insulted that someone felt I hadn't done my homework properly before making such a choice.