Why do resin prints need post-curing?

Resin prints come off the printer only partially cured. Post-curing with UV light completes the polymerisation, increasing strength by 50-100%, improving heat resistance, and eliminating the tacky surface. It also makes the part food-safer.

Can I over-cure resin prints?

Yes, excessive UV exposure can make resin prints brittle and cause yellowing (especially with clear resins). Standard resins typically need 3-10 minutes. If the surface becomes chalky or the part cracks easily, it is over-cured.

Does water curing help?

Yes, curing submerged in water prevents oxygen from inhibiting the surface cure. This eliminates the tacky surface finish and gives a harder, more uniform cure. Place the part in a clear container of water under the UV light.

Can I use sunlight instead of a UV station?

Yes, but results are inconsistent due to weather, time of day, and season. Place the print in direct sunlight, rotating every few minutes. Allow 2-3x the time compared to a dedicated curing station. UV stations give more reliable results.

3DPrintCalcs

UV Curing Calculator — Post-Cure Time & Settings

Calculate post-cure time based on UV source, wavelength and part thickness.

Part Thickness

Thickest dimension

Resin TypeEngineering/tough and castable resins need a longer cure than standard or water-washable resins.

UV SourceA dedicated turntable curing station cures most evenly; sunlight is slowest and least consistent.

UV WavelengthMatch your resin TDS — most hobby resins are 405nm. 385/395nm cure just as fast.

How We Calculate This

UV Curing Calculations

Cure time = Base time x Thickness factor x Source factor
Thickness factor = sqrt(Part thickness / 10mm)
Rotations = Based on total cure time for even exposure

Most hobby resins are formulated for 405nm, which is simply the most common LED wavelength — it is not inherently faster than 385nm or 395nm. The wavelength only matters in that it should match the absorption of your resin's photoinitiator (check the resin TDS). Thicker parts need more time as the UV must penetrate deeper, and rotating the part ensures every surface receives even exposure for a uniform cure.

Frequently Asked Questions

Related Calculators

Resin Volume Calculator

Estimate how much resin a print will consume based on model volume and supports.

Exposure Time Calculator

Calculate layer exposure time based on resin type, layer height and UV power.

Resin Cost Calculator

Work out the resin cost per print based on volume used and bottle price.

Vat Life Calculator

Estimate how many print hours remain before your FEP film needs replacing.

Layer Cure Calculator

Determine optimal cure depth and exposure energy for each resin layer.

Last updated: February 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.