The CF Sprayer is a tool used to dispense Construction Foam in the form of CF Pellets, rather than placing them one by one. Using the CF Sprayer can save up to 12 blocks of Construction Foam per shot fired, because one CF Pellet is equivalent to 13 blocks of Construction Foam when used in a CF sprayer.
Place the CF Sprayer in the middle of a crafting grid and 8 CF Pellets around it to fill it or place 1 pellet in the grid to add a small amount.
If using a CF Sprayer to spray on a Scaffold it will replace the Scaffold with Construction Foam. You can use a scaffold in combination with Construction Foam to create walls (etc.) without the need to break unnecessary, left-over construction foam. The scaffolds are dropped as entities if replaced by Construction Foam.
As of 1.70, CF will cover and harden around placed cables, allowing one to hide unsightly wiring within CF walls that are only a single block thick.