Tight spaces can be difficult to get at, typically because larger blocks and sanders won't fit into corners. Sanding tight spaces relies on small, custom tools you can fashion yourself. Sanding with your fingertips can cause blisters as well as dust, so wear bandages on your fingers and a dust mask.
Grit is the most underrated aspect when sanding wood. Check the back of the sandpaper for the size or the grit, the most common of which is 100. It removes glue, scratches, dips, gouges, stain and lacquer without going too deep. Heavier-grit sandpaper such as 80 grit can cause scratches or dips that are difficult to remove. Higher-grit sandpaper such as 180 doesn't remove material fast enough and has a tendency to polish without sanding. The all-purpose quality of 100-grit sandpaper make it the best choice for tight spaces.
Glue is the usual suspect caught in tight spaces. It oozes out corners, edges and seams when you're assembling a project. It goes unnoticed until you add stain, then it becomes glaringly obvious. Some woodworkers fold sandpaper around the end of a putty knife to sand glue from corners. This is fine for larger panels and wider applications, but putty knives are too wide and flexible to get anything accomplished in tight spaces. Cut or fashion a 1/4-by-3/4-by-3-inch piece of wood into a long, sharp wedge. Fold the sandpaper over the sharp end and use it to sand inside tight corners. The wedge works similar to a surgical tool, allowing you to sand in short, focused strokes with some power behind them. Cut the wedge smaller if needed. When you're finished, place the wedge or wedges in a drawer for easy access.
Fold a piece of 100-grit sandpaper into a sharp, knife-like edge. The sandpaper edge is stiff and slim enough to fit into the tightest of spaces. Hold it between your fingers and thumb, pushing and pulling the folded edge forward and back with short strokes. Hold the edge diagonally in the corner and use it like a mini-saw blade for a more focused approach. If the edge wears down or becomes filled with debris, fold the sandpaper again for a fresh edge. For spot sanding, roll a piece of sandpaper into a tight cylinder and use it like a pencil or dowel, twisting the end of it, to sand a single spot of dried glue or wood filler.
Dowels work well for carvings, scrolls or any tight space that doesn't conform to a strict 90-degree turn or edge. Start with a 3/8-inch dowel; if that's too small, move up to a 1/2-inch dowel. Wrap sandpaper around the dowel once, leaving the doubled-up extended edges of the sandpaper to use as a handle. If there's not enough room for the sandpaper handle, wrap the dowel completely with sandpaper and grasp it in the middle, using your fingertips to control it. Sandpaper-wrapped dowels work particularly well for flutes -- concave lines -- or anywhere curves or tight spots defy normal sanding applications or methods.
Sticky sandpaper is a contemporary innovation in sandpaper. Sticky sandpaper has a peel-off backing that allows it to stick to almost anything. Use scissors to cut the sandpaper to fit any type of wedge, dowel or tool. Fold two pieces together to create a small, saw-like tool to sand tight spots. Sticky sandpaper is tough and durable. The stiffness aids in adding pressure to tight spots when traditional sandpaper doesn't cut it.
Most power sanders are too big to fit tight spaces. Some of the smaller oscillating tools have triangular ends designed for sanding along corners and edges. Cut a piece of sticky sandpaper to fit the triangle and ease it into the corner. Larger electric sanders can be used by fashioning a wooden base with a narrow end to fit into corners. This type of sanding is aggressive and removes material faster than the manual method.