Vibrating concrete screed - video

[Jon]

Vibrating concrete screed. By Men's Craft. 9:51 video:

[Frank S]

Probably because a random orbital sander is a poor representation of a commercial vibratory device.

[hemmjo]

Actually power screeds have been around for many years. Some may have tired using small vibration devices as shown in the video but they were ineffective, so the inventor did not bother to show off their mistake.

The purpose of a vibratory screed is not simply to level the top. The purpose is to consolidate the entire thickness of the slab, eliminating voids which weaken the structure. Whatever material is shown in that video is not really concrete. There is no coarse aggregate.

This frame from the video clearly shows the screed had no effect deep in the structure, and very little near the surface. If it had worked properly, those various "layers" would have been blended. They would be no visible lines between layers. Whatever that material is, it could been easily leveled with a board without wasting time and materials on that device.