What are the differences in the various plywood types with names like CDX, MDF, MDO, OSB and so on?
Tim Inman: CDX plywood is “C” grade on one side, “D” grade (even worse) on the other side, and it is bonded for “X” exterior use. MDF is: “M” medium “D” density “F” fiberboard, sheet goods made from sawdust and glue. OSB is “O” oriented “S” strand “B” board, an “engineered” forest product made from wood chips and glue.
Carol Reed: CDX is a plywood with a “C” grade surface on one side, a “D” grade surface on the other and is glued with a exterior grade glue. It is generally used for sheathing in the construction industry. MDF is medium density fiberboard. It is quite heavy, doesn’t have a lot of structural integrity, but is relatively inexpensive and great for jigs. MDO is medium density overlay. It is used for highway signs as it has a very smooth surface great for painting. OSB is oriented strand board. It is used as sheathing plywood in the construction industry.