What does MDO plywood stand for?
MDO stands for medium-density overlay. It is exterior plywood with a resin-saturated kraft-paper face pressed onto one or both sides, and the paper is there so paint holds and the grain does not show through. That is why North American sign shops and trim carpenters treat it as the default paint-grade panel.
What is the difference between MDF and MDO plywood?
MDF is a board of compressed wood fibre with no veneer layers, so it machines cleanly for indoor doors and mouldings but does not cope with weather or wet concrete. MDO is real plywood with cross-laminated veneers, an exterior glue line and a paper overlay on the face. If the panel will be painted outdoors or used against a pour, MDO is the better fit, and MDF should stay indoors.
What is the difference between 1-step and 2-step MDO?
One-step MDO gets its paper face in the same press cycle that glues up the plywood, which keeps the cost down but can let a small core void show faintly through the face. Two-step MDO is pressed and sanded as plywood first and then overlaid in a second press run, so the face comes out flatter and more even. Ordinary paint-grade site work is fine with 1-step, while premium signs and cladding usually justify 2-step.
Can MDO plywood be used for concrete forms?
Yes, for short runs. Kraft-paper MDO leaves a smooth matte face and suits a one-off pour or concrete that will be painted, but the paper scuffs and soaks up release agent as the pour count rises. When a spec wants a matte face over many pours, MatteFace Plywood is the panel buyers often search for as MDO formwork plywood, rated up to 15 reuses on the 1S and 1SF panels and up to 25 on the two-sided Panel 2S.
What is the difference between MDO and HDO plywood?
HDO carries a much harder, denser resin overlay that casts a smooth glossy face and is made to be stripped again and again. Our HDO Basic is rated up to 10 reuses, and HDO Standard and HDO Premium up to 20. MDO has a softer paper face aimed at paint, so it is the panel for signs and trim, with only a limited forming life.
Does MDO plywood hold up to water?
MDO is water-resistant rather than watertight. Rain runs off a sealed, painted face and the exterior glue line holds up outdoors, but a fresh saw cut soaks up moisture quickly. Prime or seal every cut edge the same day, and a painted panel can stay outside for years.
