Texture help

[BedRose]

Hi,
What I am trying to do is to make a used metal texture on the first layer you have the paint job which is glossy and so, and then the next layer you have bare metal thats very reflective, the problem I am facing is I dont know where to make it so the alpha dictates where ray traced reflections will be.
Any help would be great.
With regards.

 

[Atticus]

Use a composite map on the diffusion and bump slots. In the composite map, put a couple of layers and keep in mind that the bottom of the stack is the outer layer of the texture. Make the outer map a mask and use the Alpha to mask where you want to show the other map below. You will place that map on the top of the composite stack. See that the white areas mask out (show) the secondary map, whereas the black areas leave the outer layer to show.