ModelCalcs.uk
Clamp Calculator — Sub-Assembly Clamping
Calculate clamp quantity and size needed for sub-assemblies and glue-ups.
How We Calculate This
Calculates the number of clamps needed based on joint length and the recommended spacing for your assembly type. It is a fence-post estimate (clamps at both ends plus one every spacing interval), so the count is rounded up to keep clamps within the spacing along the whole seam.
Formula
- Clamps per join = round up (Part length ÷ Clamp spacing) + 1
- Total clamps = Clamps per join × Number of joins
- Spacing: 30mm (fuselage), 35mm (hull), 40mm (wing), 50mm (structure), or your own value via Custom spacing
Example: a 200mm fuselage seam at 30mm spacing needs round up (200 ÷ 30) + 1 = 7 + 1 = 8 clamps per join.
Frequently Asked Questions
Small spring clamps (25mm jaw) are the most versatile. Bulldog clips work well for fuselage halves. Rubber bands provide even pressure over curved surfaces. Masking tape works for temporary holds. Dedicated modelling clamps from Tamiya are excellent but expensive.
Just enough pressure to close any gaps — do not over-tighten. Excessive pressure squeezes out too much glue and can deform plastic. For liquid poly cement, light pressure is sufficient as the cement welds the plastic together.
Yes. Rubber bands provide excellent even pressure, especially on curved surfaces like fuselages and hulls. Place strips of card under the rubber bands to prevent them from marking the plastic. Use multiple bands for long joins.
Poly cement: 30-60 minutes for initial set, 24 hours for full cure. CA glue: 10-30 seconds. Epoxy: varies by type (5 minutes to 24 hours). Always check the glue instructions. Longer is better for critical structural joints.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.