Outdoor wood sculpture can take many forms, from animal to human to abstract. Whether it's highly polished or hewn with a chain saw, the only limits are imagination and the size of the block of wood. The wood source can be anything from a purchased block of heartwood to the stump of a fallen tree in your front yard. Carve only wood that is free of insects, fungus and rot if you want a good shot at preserving your outdoor wood sculpture.
Watch the weather forecast for two warm, dry days for sealing outdoor wood sculpture. Try to work in the shade.
Spread a plastic tarp around the wood sculpture if it's a tree stump, or under it if it can be lifted. The tarp will protect surrounding vegetation from spilt or splashed stain. Whisk dust, dirt and wood particles from the surface of the wood sculpture so that stain will sink in evenly.
Apply the first coat of semi-transparent penetrating stain with a paintbrush. Dot it into crevices of rough surfaces and use long, even strokes for smooth surfaces. Cover the surface as quickly as you can, to avoid leaving overlapping marks as the stain penetrates.
Apply the second coat within two hours, or before the first coat dries. If the first coat has dried in some areas, you'll see shiny spots where the second coat cannot sink into the wood. Wipe excess stain away as you go, with a soft cloth or damp sponge.
Allow the stain to cure for two days, then tip the sculpture onto its side and stain the bottom in the same manner. This will protect the bottom of the sculpture from insect damage and rot from fungus or bacteria.
Use a semi-transparent penetrating stain that contains a fungicide to delay rot and prevent mildew. The double-coat method of staining outdoor wood can last as long as 10 years, while waterproof sealers must be applied every one to two years.