I’ve been doing some hammer veneering and entered the world of hot hide glue (another discussion, lets just say I’m intrigued liking it for veneering). 

I’ve seen some people prep the surface of the substrate with a toothing plane & lacking one, I’m wondering if a coarse sandpaper would achieve the same result?

I’ve never done any type of prep with plywood and never had an issue, but I’m wondering if a quick sanding with 80 grit is a good thing.