YouTube - Sandblasting antique lawn chair
This is a video of me sandblasting a steel chair. It's a piece of cake. "Rust Ban" will prevent flash rusting and can be painted over without further cleaning or rinsing.
You'll notice in the video, the sand inlet hose is always held above the nozzle and the gun is rested with the nozzle in a downward position. This keeps water from tricklin back into the sand hose. If the sand gets wet, it won't draw.
This is the "medium duty" kit from Ultimate Washer, but can be had for less.
It's all you'd need for occasional use.