How to check that powder coating is fully cured.

Steps

1. Measure metal temperature

   Run an oven data logger with probes attached to the parts, including the thickest sections. Record how long each part stays at or above the TDS cure temperature.

2. Compare with the TDS

   Check that every probe falls inside the cure window, not just the average.

3. Do a solvent rub test

   A common check is rubbing the film with a cloth soaked in MEK and judging any softening or colour transfer against a known well-cured panel. Agree the number of rubs and pass criteria with your supplier.

4. Check mechanical properties

   Run your usual impact, bend or cross-cut adhesion tests. Poor results can indicate undercure.

5. Look for overbake

   Compare colour and gloss with the approved panel; yellowing, especially with epoxy whites, suggests overbaking.

Parameters

Cure schedule

per TDS (metal temperature × time)

Temperature measurement

Oven data logger on parts

Solvent rub

Method and pass criteria agreed per project

Mechanical checks

Your usual impact, bend, adhesion tests

Common mistakes

• Setting cure by oven air temperature only.
• Logging only light parts when heavy sections share the load.
• Judging cure by surface hardness or appearance alone.
• Ignoring yellowing as a sign of overbaking on epoxy and pale colours.