In addition to the cutting tools, you will need an assortment of different size sanding blocks. These are indispenable tools for model construction. You can buy ready-made sanding blocks or make your own. Use three screws along one edge to hold the overlapped ends of the sandpaper in place. Use 80 grit garnet sandpaper on the block during general construction.
Most hardware stores carry a rack of aluminum in various sizes and shapes.
This long sanding block is very helpful for shaping leading and trailing edges, and other large pieces, accurately. Last but not least, glue sandpaper onto different sizes of scrap plywood sticks and round hardwood dowels. These are handy for working in tight places and for careful shaping where a big sanding block is too hard to control. In selecting balsa sheets for use in your model, it is important to consider the way the grain runs through the sheet as well as the weight of the sheet. The grain direction actually controls the rigidity or flexibility of a balsa sheet more than the density does.