Which of the following materials should not be cut with a surform?

The material that should not be cut with a surform is body filler. Surforms are primarily designed for shaping and smoothing materials like wood and softer plastics. They utilize a fine, perforated blade, which allows for effective removal of material while also producing a smoother finish.

Body fillers, however, are often denser and more brittle than woods and plastics. When attempting to cut or shape body filler with a surform, the material can clog the blade or create uneven surfaces, as surforms are not intended for the refinement of such materials. Instead, body filler is best managed with different tools, such as sanding blocks or razors designed for that purpose, which can maintain better control and achieve the desired finish without damaging the filler itself.

In contrast, woods and softer plastics are appropriate candidates for surform cutting, as the tool can effectively remove material to create the necessary shapes and profiles. Surform usage on metals is discouraged due to the tendency of the metal to dull the blade quickly and may not produce the intended finish, but it still may be worked on with more appropriate metalworking tools. Thus, the specificity of body filler as the unsuitable material distinguishes it in this context.