how long till this guy disappears?

Unfortunately, this guy in the video shows a fake, he uses fishing wire to hang this device in the air.  

I saw one of his videos where he takes a long tree branch and waves it over the device as it hovers, then walks around the perimeter of the device with the tree branch held vertically.

So I'm not sure this is the explanation.

At time 23:00, he passes a hoop over the entirety of the hovering device, showing no lines or wires can be holding it up.

Here's a potential explanation:

On The Classical Coupling Between Gravity and Electromagnetism

http://www.mdpi.com/2218-2004/3/3/320/pdf

It will be shown that there is an upward force on an electron positioned at the center of a positively-charged shell in the presence of a uniform gravitational field. This electric force can be made equal in magnitude to the gravitational force on the electron at a shell voltage of approximately 1 MV. Moreover, the electric force is gravitationally induced, and the balance is unaffected by the magnitude of the gravitational force.

In the absence of gravity, the electric field of a point charge is simply a Coulomb field. However, in the presence of a gravitational field, the Coulomb field becomes distorted.

Gravity is an effect of the non-zero expectation value of the Quantum Vacuum. It is, in effect, the Casimir Effect,writ large.

http://article.sciencepublishinggroup.com/pdf/10.11648.j.ijass.s.2014020601.11.pdf

Quantum vacuum energy, gravity manipulation and the force generated by the interaction between high-potential electric fields and zero-point-field

In modern physics the “vacuum” cannot be considered, due to Heisenberg uncertainty principle, as a void but as physical entity manifesting a complex and fundamental background activity in which, even in absence of matter, processes like virtual particle pair creation – annihilation and electromagnetic fields fluctuations, known as zero point fluctuations (ZPF) continuously occur (see Fig.1). The physical reality of ZPF, also known as Quantum Vacuum (QV), has been proved to give measurable effects for the first time by Casimir’s experiment in 1948 [1] and next confirmed by Lamoreux [2], Milonni et al. [3]. From a more theoretical point of view, Russian physicist Andrei Sakharov, in searching for deriving Einstein’s phenomenological equations for general relativity from more fundamental set of assumptions, came to the conclusion that general relativistic phenomena could be seen as induced effects brought about by changes in the quantum-fluctuation energy of the vacuum due to the presence of matter [4].

Based on the Sakharov’s hypothesis, Puthoff [5] explored a conceptually simple, classical model according to which gravitation could be not a fundamental interaction at all, but rather an induced effect due to changes in the quantum-fluctuation energy of the vacuum when matter is present.

So if this device works as he claims, he's apparently generated a large electrostatic field of one polarity which is "bowed" by gravity, and in the center of that electrostatic field he's generated another electrostatic field of opposite polarity, imparting a repulsion to the device. The spin is for gyroscopic stability, although the angular momentum of the electrons on the spinning charged plates may contribute somewhat to the interaction with the gravitational field.

Apparently a single electron's size is so small that it requires 1MV to counteract gravity upon that electron, but the increase in surface area of his device acts to increase lifting surface area.

There is such a thing as gravitoelectromagnetic coupling, but it's been measured to be extremely weak with all experimental setups thus far. Perhaps it's just weak, perhaps the setups weren't optimized... time will tell. It is known that a large inertial change (or a change of reference frame) of a charged particle raises the coupling coefficient, as I explicated in my triboelectric charge-separation motor thread (which didn't seem to survive the transition to the new server).

Here's an explanation of the triboelectric charge-separation motor idea, all that survived the move to the new web server:

Another applicaton is my triboelectric charge-separation motor idea, operating upon the same principle as the Searl device (but much simplified and more direct). It steals bound electron orbital momentum and uses it in attempting to conserve the angular momentum of the permanent magnetic field and the frame-dependent magnetic field, resulting in a unidirectional rotation. The bound electrons regain their usual orbital momentum by absorbing energy from the quantum vacuum. This device should also exhibit gravitoelectromagnetic coupling via a large electron accelerational change... gravitoelectromagnetic coupling is miniscule at low electron velocity, but a large rate of change of electron velocity implies a larger coupling coefficient. My triboelectric charge-separation motor idea utilizes such a large rate of change of electron velocity via a geometrical transform. This change of reference frame makes the electron transition from stationary (in the rotor's frame) / rotating (in the lab frame) to rotating in the opposite direction (in the rotor's frame) / stationary (in the lab frame). Gravity is a uniform acceleration, and it does distort a Coulomb field. Thus the inverse (an electron's acceleration distorting the gravitational field) should also take place.

http://article.sciencepublishinggroup.com/pdf/10.11648.j.ijass.s.2014020601.11.pdf

The above discussion shows that gravity could be considered as a function of QV energy density since both G and gravitational mass can be expressed as QV functions. This means that, from a theoretical point of view, gravity manipulation is possible, provided that we are able to modify the local value of ρ_QV , for example by altering ZPE.

This is exactly how magnetic attraction and repulsion works. See my thread here.

What does all this mean? Well, eventually we'll learn how to manipulate not only gravity, but inertia. Think of the ramifications of that... Tron bike, anyone?

As with any technology, this has benefits and potential misuses. Imagine negating the inertia of, say, a concrete bunker's wall, thereby allowing a projectile to more easily deeply penetrate.