The Secret of Corrugated Plastic: Why “Vertical Flutes” Are Crucial for Yard Signs

If you are new to ordering blank yard signs or bulk corrugated plastic, you might overlook one of the most critical manufacturing details: the flute direction. Corrugated plastic boards have a hollow twin-wall structure with internal ribs called flutes.

For standard yard signs (typically 24″ wide by 18″ tall), the flutes must be vertical—meaning the internal tunnels run along the 18-inch height. Why is this so crucial? Because this vertical alignment is what allows the prongs of your metal H-stakes to slide directly into the bottom of the sign. If you accidentally order boards with horizontal flutes, your wire stakes will have nowhere to go, rendering the boards useless for lawn displays.

At Mcoro, all our 24″x18″ sign blanks are precision-cut with guaranteed vertical flutes. Combined with our 4mm thickness, they provide the perfect, snug fit for our 3.7mm (9-gauge) wire stakes, ensuring a damage-free and secure setup every time.