Can I Use an IR Thermometer to Monitor Curing?

Many professionals wonder, “Can I use an IR thermometer to monitor curing accurately?” Understanding the precise conditions needed for curing powder coating is crucial.

You’re staring at your oven.
Your IR thermometer says 400°F.
The powder flowed out.
Looks cured.

But the real question is: Is the part actually cured or just cooked on the surface?

If you’re relying only on an infrared (IR) thermometer to monitor powder curing, you could be headed straight for soft finishes, coating failure, or customer callbacks.

Let’s break down how IR thermometers work, when to use them, and most importantly, why they can’t be your only curing tool.

First, What Is an IR Thermometer?

An infrared (IR) thermometer measures surface temperature without contact. You point the gun at the object, and it reads the thermal radiation bouncing off.

It’s fast, convenient, and widely used across industries, especially for checking powder coating ovens.

But there’s a catch...

IR Thermometers Can Lie (Sort Of)

Here’s the kicker:
IR thermometers only measure surface temperature, not the actual internal temperature of your part.

That means:

• A shiny or reflective surface can give a false low reading

• Dark, flat surfaces may appear hotter than they really are

• Parts with uneven thickness heat unevenly (but IR only shows what it sees)

Think of it like measuring how hot a steak is just by touching the top, without cutting into it. That’s IR.

Can You Use an IR Thermometer? Yes, But With Caution

IR thermometers can be part of your process, just not the whole thing.
They’re great for:

• Quick spot checks

• Confirming oven uniformity

• Estimating surface heat on large batches

But for precision curing, especially on critical jobs?

You need more.

The Gold Standard: Thermocouples on the Part

A magnetic thermocouple probe placed directly on the part tells you:

• When the part itself reaches the correct cure temperature

• How long it stays there

• What your actual part temperature profile looks like over time

Start your cure timer only when the part, not the air, hits the required temp.

Real-World Example

You set your oven to 400°F.
Your IR thermometer shows 400°F on the part’s surface after 5 minutes.
You start the 10-minute cure timer.

But here’s what’s happening inside:

• Surface: 400°F

• Core metal: 320°F

• True part cure temp won’t be reached for another 4 - 6 minutes

Result? Undercure.
It looks good… until it chips, fails a rub test, or fades early.

What Happens If You Rely Only on IR?

• Undercured powder: looks fine, fails fast

• Color mismatch on critical color jobs

• Lost gloss or brittleness if overcured from guessing

• Inconsistent batches if part thickness or placement changes

Best Practices for Using IR Thermometers in Powder Coating

1. Use on consistent, coated surfaces only
   Avoid chrome, shiny metal, or uneven geometry.

2. Use black high-temp paint or tape on the spot you want to measure
   This improves emissivity and gives accurate readings.

3. Use IR as a pre-check, not a cure trigger
   Let it help you decide when to probe with a thermocouple — not replace it.

4. Record your readings and part times
   Build a repeatable process based on verified data.

Joey’s Final Word: Trust the Process, Not the Shortcut

An IR gun is a helpful tool.
But curing powder right requires more than convenience, it requires precision.

“IR can tell you when to check, but it can’t tell you when it’s cured.”

Invest in a thermocouple. Use it often.
And when it comes to powder coating quality, remember:
Almost right is still wrong.