With a Thinline one of the “problem” areas is inside the “F” holes…I have found a supplier of some most unique tools specifically designed to sand in difficult places… I’d tell ya where to get them, but such exotic tools are so very expensive, you couldn’t afford ‘em anyway…
I reach in, and pull any wood fibers out and sand ‘em away.
Ready for a bit of color….
Since this guitar will be an amber/orange shade… I like to start with something other than a nude bare piece of wood.
So I give it a wash of a base shade, yellow in this case…
Ron Kirn