I have shaped my second EPS Soap Bar with a plywood stringer but it is protruding slighly and I want to take it down level to the EPS before glassing, same as a standard blanks stringer.
I have tried my bullnose plane but is does not like it, the ply is the finest I could get 1/8th and glued in with caskamite epoxy boat glue and goes with the grain on the 2 outer skins. Shaping has been easy but the concave between the fins is where the stringer needs addressing. I have thought of using a mini sanding disk on my drill.
I know I will get some good answers here so look forward to hearing from you.
http://www.highlandwoodworking.com/ibexluthiersconvexsolefingerplane25mm.aspx. Not sure if this is the one that I have size wise. But this is the tool. Very precise and razor sharp. Don’t have my ruler handy, but the one I have will fit an 1/8" stringer and barely touch the foam. Perfect for eps. The convex bottom is the winner and you can find it cheaper than the link I listed, that was just to show a picture.
In small areas like your concave between the fins, or at the rails on multi-stringers, use the small spokeshave. Tape the foam on either side of the stringer and use the tool in short pulls, more like whittling than a planing movement . Once most of the wood is removed and you have about 1/64 -1/32 sticking up, use a longer movement. Never use a power sander/grinder on the stringer except at the nose and tail and even then nothing bigger than 4" max.
