Quote - Okay I took your image above and ran with it - hope you don't mind.
Here is a color map amd a bump (texture) map - just cut the image in half, save as their own TIF image and put them on a wall to see what it is.

The light colored wall and the maroon bands are seperate layers (I also added color to your rust, and some streaks that aren't that noticeable) that I masked part of to see the nasty rust texture underneath. You can also use this technique to have cement block, bricks, wood, whatever you want underneath as well.

Lemme know if this is something you're looking for - hope it helps!
-Lew ;-)

No, not really because the background looks too different to the damaged part - it all has to look like one texture when it's done.

It may even turn out that what I was trying to do with making PART of a layer transparent may not be the way to get the end effect I want - but at least I now know how to do that - in case it helps. 

But I think the only way is to keep going and finish the tutorial I started and see what the end result is like.

Because I found myself halted in doing the tutorial I couldn't sit staring at the computer screen until help arrived, (I mean it could be hours or even days!)  I had to go off and do something else while I waited... and of course doing that you loose track of how the tutorial was going and of how you were thinking at the time that you could take it in your own direction.

Measure your mind's height
by the shade it casts.
Robert Browning (Paracelsus)

Fran's Freestuff

http://franontheedge.blogspot.com/

http://www.FranOnTheEdge.com