WoodCalcs.uk
Clamp Pressure Calculator — Glue-Up Force
Determine clamp force and number of clamps needed for glue-ups.
How We Calculate This
Total force (kgf) = Pressure (kPa) × 1000 × Area (m²) ÷ 9.81
Clamps = Total force ÷ Force per clamp (~250kgf for a light-duty F-clamp)
Softwood needs ~690-1034 kPa (100-150 psi). Hardwood needs ~1207-1724 kPa (175-250 psi).
Frequently Asked Questions
PVA/Type-I aliphatic glue (Franklin/Titebond) needs about 100-150 psi (690-1034 kPa) for softwoods and 175-250 psi (1207-1724 kPa) for hardwoods, rising towards 300 psi for very dense species such as oak or maple. Over-clamping squeezes out too much glue and starves the joint; under-clamping leaves gaps.
Space clamps 200-300mm apart for edge-glued panels. Alternate clamps above and below to prevent bowing. A 600mm wide panel typically needs 3 clamps per glue line.
F-clamps (bar clamps) are the most versatile. Sash clamps for long panels. Pipe clamps are economical for wide panels. Spring clamps for light-duty work. A light-duty F-clamp delivers around 270 kgf (~600 lbf); medium and heavy-duty F-clamps reach 500-600 kgf (~1100-1320 lbf). The 250kgf default is a conservative light-duty assumption.
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Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.