Recently, I tried weathering with salt as described in a July 2003 FineScale Modeler article. The idea is, after base-coating a model, wet an area you want to appear chipped, sprinkle it with salt, and apply a top coat. When that's dry, rub away the salt to reveal the paint color underneath. Two problems: One is scale; salt works well on large-scale models, but the grains look too bug for 1/48 scale and smaller. Second, the partially dissolved salt leaves a residue on the model that affects the color. So, I tried sand. I cleaned small amounts with water, then let the sand dry on cheese cloth. The process is the same as with salt: Wet the model, apply sand, paint, and rub away. I use different sands for different scales: Brick or silica sand is great for small scales; construction or playground sand is better for larger items. Sand doesn't dissolve, so there's no residue to remove -- and my wife doesn't go crazy looking for the salt.
Tip submitted by:
Favian SciosciaToronto, Ontario, Canada