by Jon Elvrum
We have been using veneer core ply for many years for cabinet carcasses. Our supplier touts the benefits of MDF (Medium Density Fiberboard) core products but I have my doubts. MDF is heavier and our tests show that screws can be troublesome. What are the advantages?
The primary value of MDF or particle board over veneer core plywood is its dimensional consistency and stability. Veneer core plywood contains internal gaps called voids. There is no way a plywood manufacturer can avoid creating them.
Very thin core layers like those found in Baltic birch come as close as anything to neutralizing the effect of voids, but since voids are unpredictable and uncontrollable, there are sometimes compression dips in the surface of these panels. Current US Government regulations allow 3/32 variation within the panel. (When you look at a section cut, substantial gaps are evident in several layers of the cross-banded veneer.)
MDF and particle board are relatively free of this problem. When drilling, you are always looking for material consistency. In recent years MDF manufacturers have reduced board weight about 12% and advances in fastener design have improved screw holding power. New screws, designed for this material, have threads with higher, wider pitch that grab and hold well in these new composites.
Only your testing these materials will certify that they are correct for you or not. Contact your board supplier, or the Particle Board Association.
Jon Elvrum, Director of Distribution and Sales at Ritter Manufacturing in Antioch California, is also a well known author and consultant to the cabinetmaking industry. He has written numerous articles on the 32mm cabinetmaking system and production woodworking in general.