In this video, we share a process we have been perfecting for several years now. Converting a "Linear" Fresnel lens into a "Spot" Fresnel lens. Rear projection TV screens all have a circular Fresnel pattern on one side. A Spot Fresnel lens has a glossy smooth finish on the second side of the lens while a Linear Fresnel lens has vertical grooves that are very small, almost too small to see with the naked eye on the second side. By filling these grooves in with either resin, gloss enamel paint or removing them with a buffing process, the Linear beam becomes a Spot. This results in a clearer lens allowing more sunlight to pass through to the target area and because the focal pattern is tighter, the maximum temperature is increased dramatically. Sanding and buffing is the best option because there is less chance of unrecoverable errors that can occur with the other processes.