Gents,
I'm just about to purchase my first wetstone, the Norton 4k/8k combo stone, but have read here (and elsewhere) that the stone should be lapped before use to ensure a flat surface since the Norton's aren't usually perfectly true to start with.

I don't really fancy buying the $30 flattening stone, although I will if needs must, but I am really looking for a less expensive alternative. I've heard something about using a piece of plexi-glass and high-grit wet sandpaper, but can't for the life of me figure out how you would do this? Hold the sandpaper to the plexi like a sanding block? Glue the sandpaper to the plexi and run the Norton over the plexi?

Can someone please explain to me the best (inexpensive) way to lap a Norton? Details are certainly welcomed for this newbie!

Thanks,

Mark