While cutting card or balsa wood may not seem like a fine art, it is probably the most difficult aspect of model making. The results easily distinguish the amateur from the professional. By learning the basics correctly and eliminating bad habits, professional standard models can be achieved with little practice.
Steps1Prepare your work surface. Make sure the cutting mat is flat to the table top and that there is a nice even, stable surface to work on. Clear a space to the side to make room for cut outs and have a bin nearby to toss small unusable scraps into.
2Mark your cut lines. Using the drawing tools if necessary, lightly draw the desired shape at least a 3/4 inch from the edge of the card. Do not be heavy handed with the pencil - draw the line just so that it can be made out clearly and cleanly erased.3Use a steel ruler and blade for straight cuts. The majority of cuts made in model making are straight lines. It is important to know the best way to hold the steel ruler and blade. Place the ruler under the cut line. Put pressure on the ruler with fingers; it should be hard to the card or balsa surface. Use the blade lightly, applying minimal pressure to the material surface with it. Keep the blade perpendicular to the card surface to achieve an even, un-slanted edge.
4Score when needed. Using the blade lightly in this manner is known as scoring. Repeatedly score along the cut line, using the ruler to guide the blade and keep it straight, until it cuts cleanly through the material. Card and balsa are made of many tiny, thin layers. Scoring allows the blade to cut through each layer cleanly. Applying a lot of pressure to the blade crushes these layers. This, along with uneven pressure application along the cut line, leads to frayed, uneven edges.5Extend the lines for clean cuts and corners. When scoring along a cut line, begin an inch or so before the cut line starts and keep cutting after it ends i.e. Score a longer, extended line than the one actually desired. As lighter pressure is applied naturally at the beginning and at the end of the cut, an even edge is assured along your cut line. This method also ensures cleaner corners when cutting your perpendicular lines.
6Remove the piece gently. If cut cleanly and correctly the shape should simply pop out of the card or balsa with a gentle push. If it doesn't, don't force it out. Run the blade in the cut lines again, remembering to extend beyond the lines, to cut any remaining fibers.