The Hub

So this 310 came into the shop and had a pretty gnarly crack that splinters some toward the lower left bout. Going to do a crack repair with the TJ Thompson crack corrector and some hide glue. The issue I'm inquiring about is the finish is delaminating around the area. I'm curious as to what type of finish it is. Seems a bit flexible and spongy to be a nitro alone. There's shards of finish missing, and dirt has found its way underneath…