Hobby knife
The hobby knife is the most important tool in any modeller's workshop. The most popular type uses replaceable no. 11 blades (pointed) in a no. 1 metal handle. These blades are perfect for precision cutting of balsa, card and film. For curved cuts, no. 10 blades (rounded) work better, and for heavy-duty work use no. 24 blades (trapezoidal).
A key rule: a dull blade is more dangerous than a sharp one because it requires more pressure and slips more easily. Change blades often – in balsa one blade lasts about 20–30 minutes of intensive work. Popular brands include X-Acto, Olfa, Excel and Proedge. Always cut away from your body, on a self-healing mat, and never leave a knife on the edge of the table.
Glues
Cyanoacrylate (CA) glue comes in three viscosities: water-thin penetrates capillary gaps and sets in 3–5 seconds, medium gives a dozen seconds for position adjustment, and thick fills gaps and sets in 20–30 seconds. Use thin CA for well-fitting balsa-to-balsa joints, medium for rib assembly and structural nodes, and thick wherever you need to fill irregularities.
CA accelerator (kicker) cures the glue instantly but reduces joint strength by 10–20%. Use it only where speed matters more than strength. Five-minute epoxy is suitable for motor mounts, landing gear and other joints that must resist vibration. Thirty-minute epoxy allows time for precise positioning and is stronger.
White glue (PVA, Titebond) is ideal for balsa joints in free-flight models where minimum dry weight matters. Clear contact adhesive (e.g. UHU Por) works well for attaching covering film in areas the iron cannot reach.
Sandpaper and shaping
Choose sandpaper by grit: P80–P120 for rough shaping of airfoil profiles, P180–P240 for general sanding and leveling, P320–P400 for smoothing before covering, and P600+ for polishing painted surfaces. Use dry paper on balsa and wet-and-dry on paints and fillers.
A sanding block is essential – bare paper in the hand produces uneven surfaces. A flat block of cork or rigid foam ensures a true surface. For shaping leading edges, use an oval block or a tube wrapped in sandpaper. Needle files (round, flat, triangular) are useful for precision work in tight spaces.
Balsa and fibreglass dust is harmful – wear a dust mask during heavy sanding and vacuum the work area. Always sand in the direction of the wood grain, not across it.
Measuring tools
A 30 cm and a 60 cm steel ruler are fundamental – they serve both for measuring and as a guide for knife cuts. Plastic rulers are quickly damaged by blades and give inaccurate guidance. A caliper (preferably digital) is indispensable for measuring rib thickness, rod diameter, checking profile dimensions and many other tasks.
A set square lets you check that fuselage and wing joints are perpendicular. A protractor with a spirit level (inclinometer) is used for setting incidence angles. Advanced modellers also benefit from a digital scale accurate to 0.1 g for checking component weights and balancing.
Holding and assembly tools
Flat-tipped tweezers hold small parts during gluing, such as fabric reinforcements, decals or tiny details. Flat-nose and round-nose pliers help with bending undercarriage wire and control linkages. Dressmaker's pins (steel, not plastic-headed) are essential for pinning parts to the building board while glue dries.
Spring clips (miniature clamps) replace pins where they cannot be driven in. Rubber bands press parts together during gluing – wrap them around the fuselage or wing. A press made of small boards and wing nuts is useful for laminating and edge-gluing balsa sheets.
Building board and work surface
A building board is an absolute workshop essential – wings and stabilizers are built on it to guarantee flatness. The best option is 8–10 mm cork sheet glued to an MDF or chipboard panel. Cork accepts pins easily and does not dull blades.
Alternatives include suspended ceiling tiles (polystyrene) or a self-healing mat. Before building, tape the plan to the board and cover it with cling film or self-adhesive film to prevent the structure from being glued to the plan. The board should be larger than the biggest part you build – for a 1 m wing you need at least 110 × 30 cm.
Covering tools
A modelling iron (e.g. Top Flite MonoKote Iron or an inexpensive Chinese equivalent) with adjustable temperature is the key to a good film finish. Temperature is matched to the film type: Oracover needs about 150–170 °C for adhesion and 200 °C for shrinking; Japanese films (Ecoat, Toyo) have different parameters.
A heat gun with temperature control is used to shrink film on large flat surfaces. The long flat shoe of the iron works better on edges and along ribs. For Japanese tissue covering, nitrate dope applied by brush is the standard – a soft flat brush and a solvent container are needed.
Workshop organisation
Good lighting is critical – an adjustable-arm LED lamp should shine from the side so that shadows reveal surface irregularities. Ventilation is necessary when working with CA (fumes irritate the eyes), epoxies, dopes and solvents. An open window is the minimum; a small extraction fan is a better solution.
Store CA glues in the fridge – this doubles their shelf life. Keep blades, pins and small parts in containers with lids. The most-used tools (knife, glue, ruler) should have a fixed spot within arm's reach. Store balsa and strip wood flat to prevent warping. Keep a fire extinguisher or fire blanket nearby – CA glue and solvents are flammable.