These are unlike processes applied to achieve different results. The only similarities are basic: each is a process of propelling media at a high velocity to strike a surface. Shot peening however requires control over a consistent size and shape of media, a consistent velocity of media, a consistent volume of media striking each surface area, and for a consistent length of time. Careful controls yield consistent and repeatable results that are not measurable visually. Blast cleaning is ordinarily less controlled, therefore less expensive, and results can usually be assessed visually.