Scaffolds are easy to place construction helpers that are slightly unstable and need to be supported by other scaffolds below,
They are easy to set up / demolish AND act as ladders for reaching the building height easily.
They are very good for building structures with CF.
Rightclick: Places one Scaffold (as normal)
Leftclick: Places one Scaffold on top of the scaffold you clicked on. (Of course this only works if you have already placed one Scaffold)
You may reinforce Scaffolds by using additional sticks.
Right-clicking on an existing scaffold with a stick will reinforce it. This will consume 2 sticks. The scaffold being reinforced must also be part of a pillar of scaffolds connected to the ground.
Once a scaffold has been reinforced, you may then place additional scaffolds adjacent to it, over air blocks, up to 4 blocks away. Those scaffolds may then have additional scaffolds connected to them as well, up to 1 block away.
This feature allows for expansive scaffold 'flooring' in high areas and greatly assists with placement of CF in otherwise tricky areas.
Note that when a reinforced scaffold is broken, you will get 2 sticks and a scaffold back. Thus, nothing is wasted when reinforcing a scaffold.
There is also an iron version.