Thanks for the replies.
If I'm honest, I'm not sure that I've got anything in mind, I'd just like to have a look at some guides to see how it's done, and whether I think I'm capable. I've built plenty of kits, mostly plastic, but a couple of white metal as well. Partly I'd like to detail some RTR models, partly I've always liked the idea of building something from scratch.
I can grasp how a shape like a boiler is produced, but how about say a Belpaire firebox? Cylinders? Rivets? How do you form the shape of the noise of a diesel, say a baby Deltic?
Cheers N