Question: is mdf any good for shelves?
Answer: MDF is commonly used for shelving in closets and cabinets because it's inexpensive and smooth. But MDF isn't as stiff as plywood and will sag over time. ... The MDF edge will absorb a lot of glue, so spread on a light coat, give it a minute to soak in, and apply another bead before you add the wood nosing.