ModelCalcs.uk
Putty Usage Calculator â Gap Filling
Calculate modelling putty volume needed for gap filling based on seam length, width and depth.
How We Calculate This
Volume Calculation
Volume per seam = Length x Width x Depth
Total volume = Volume per seam x Number of seams
Total with waste = Total volume x Waste factor (accounts for overfill and sanding)
Weight = Volume x Putty density
Frequently Asked Questions
For small gaps, liquid poly cement pressed into seams works well. For medium gaps, Tamiya Basic putty (polyester) or Mr Surfacer 500 are popular. For large gaps, Milliput or Green Stuff epoxy putties are better as they do not shrink. CA glue with accelerator is fast but hard to sand.
Dry-fit the parts and look at the join under a bright light. Gaps under 0.3mm can often be closed with thin cement and pressure. Gaps of 0.3-1mm suit standard putty. Gaps over 1mm may need strip styrene backing before filling.
Typically 30-50% of the applied putty is sanded away during finishing. This calculator includes a waste factor to account for overfill and sanding. Apply slightly more than needed and sand back to the surface for the smoothest result.
Related Calculators
Filler Calculator
Estimate putty or filler needed for seam lines, gaps and corrections.
Parts Count Estimator
Estimate total parts count for a kit based on scale, subject type and complexity.
Glue Amount Calculator
Calculate how much plastic cement or CA glue you need for your kit build.
Rigging Calculator
Calculate rigging line lengths for biplanes, ships and other rigged models.
Photo-Etch Calculator
Estimate CA glue and tools needed for photo-etch detail sets.
Was this calculator helpful?
Last updated: March 2026
All calculations are estimates. Always verify quantities before purchasing materials.