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Homemade Pressure Sandblaster

Sandblasters are amazingly effective at removing scale and rust, and prepping a surface to be welded, painted or restored. Compared to alternatives like hand sanding, sandblasting can be a near-magical improvement. They're not especially complicated. Systems include a compressor, air reservoir, hose and sandblast nozzle. You can build nozzles. But, because sandblasters and sandblasting equipment has become very affordable, consider making a high-quality system by assembling off-the-shelf parts.
  1. Top Feed

    • There are only two main designs for sandblasters: top feed and bottom feed. In top-feed systems, sand or other abrasive media will be introduced to a pressurized air stream from above using gravity. Your choice of media may determine which is a better design. (Lighter and smaller media works better with vacuum pressure.) You'll do best by repurposing an existing trigger-actuated air nozzle with threads to an air hose. An air nozzle for a compressor or an old paint spray gun may work. You can mount any kind of hopper above the stream of air. Make a small passageway, like a carburetor jet, between the hopper and the air stream to let the media fall through at a metered pace, like an hourglass. The attachment doesn't have to be pretty. You can even use epoxy to attach the hopper to the trigger mechanism.

    Vacuum Feed

    • Vacuum-feed sandblasters' trigger mechanism can be nearly identical to gravity-feed units, but they require a little more precision and forethought. You can't just dump media into an air stream and know it will work. You have to drill a hole into the nozzle and know that air passing through it will create enough vacuum to suck media into the air stream. When in doubt, start small, working up to a bigger hole. The simplest systems may just suck media from an air stream through a flexible tube lying in a bucket of sand.

    Reservoir

    • The problem with most sandblasting systems used for all but the smallest jobs, is the difficulty in moving such a large volume of air. If you use a typical air compressor, like contractors use for nailing guns, you'll quickly encounter this problem. They have small air reservoirs. As soon as the pressure in the reservoir is depleted, the compressor's motor turns on to pressurize more air. Very few compressor motors can keep up with the air volume demands of a sandblaster, forcing you to continually wait for pressure to be built. A great homemade solution is to connect an overflow reservoir to a small contractor's compressor.

    Auxiliary Reservoirs

    • If you're a skilled welder, you could make an overflow reservoir. You're better off buying one or repurposing an existing tank. Rather than the typical 2-gallon capacity of a contractor's compressor, you want something with 40 gallons of capacity or more. You may be able to repurpose a propane-type tank -- however, make absolutely sure there are no remaining vapors. You may need an adaptor to connect an air hose to and from it. Your air supply should go from your compressor to your auxiliary reservoir and then to your sandblasting nozzle, which is connected by hopper or hose to your media supply.


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