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Powder coating vs. liquid paint


Both protect metal. They do it differently, cure differently and cost differently. Here is how to decide which one belongs on your print — before the drawing is released.

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It is the question we get more than any other, and the honest answer is that neither process is better — they solve different problems. What follows is how we actually decide when a print lands on the desk.

The short version

Choose powder when…

  • The part can take an oven cure (roughly 350–400°F)
  • You want maximum film durability and impact resistance
  • The surface area is large and cost per part matters
  • You need a textured, veined or wrinkled finish
  • Corrosion protection is the primary job

Choose liquid when…

  • The substrate or assembly cannot be baked
  • The drawing calls out a specific military or aerospace system by number
  • You need a thin film or a tight dimensional tolerance
  • The part is already assembled with heat-sensitive components
  • You need a Class A cosmetic finish
The real differences

Four things that decide it

1. Heat

Powder is applied dry and then melted, gelled and hardened in an oven. That cure is non-negotiable. If your part has plastic components, pressed-in bearings, electronics, adhesives, or a heat treatment you cannot disturb, powder is out before the conversation starts. Liquid coatings cure at ambient or with low-temperature force-dry, which is why they dominate on assemblies.

2. Film thickness

A typical powder film runs meaningfully thicker than a typical wet-paint film. That thickness is why powder wins on durability — and why it loses when a part has close-tolerance mating surfaces, threads that have to gauge, or a stack-up that a few thousandths would break. Call out your maximum film thickness on the print and we will tell you which process can hold it.

3. What the specification says

This one ends the debate more often than engineering does. Military and aerospace drawings call out specific liquid systems by number — a primer per MIL-PRF-23377 or MIL-DTL-53022, a topcoat per MIL-PRF-85285 or MIL-DTL-53039. If your print says that, powder is not an alternative no matter how much better it would perform. The spec is the spec.

4. Cost at volume

Powder generally wins on cost per square foot at production volume, partly because overspray can be reclaimed and partly because it is a faster single-coat process. Liquid systems that require a pretreatment, a primer, a topcoat and a cure between each are inherently more labour. On a prototype run the difference is small; on 5,000 parts a month it is not.

Where people get it wrong

Three mistakes worth avoiding

Specifying powder on an assembly

We see this regularly: a welded frame with a pressed bushing or a nylon insert, spec’d for powder. It arrives, and now somebody has to decide whether to disassemble it or change the finish. Decide before the drawing is released.

Ignoring the pretreatment

Neither process sticks to a dirty or improperly prepared part. Phosphate systems, blasting and chemical conversion are not optional extras — they are most of what determines whether the finish survives salt spray. If the print is silent on pretreatment, ask.

Treating color as an afterthought

Powder and liquid do not hit the same color identically, and not every color exists in every chemistry. If a part has to match an adjacent component, tell us at quote time so we can pull a physical panel rather than guess from a screen.

What if the answer is both? It happens more than you would expect — a chassis that gets powder and a bracket in the same assembly that has to be liquid to hold a spec. We run both processes in the same building in Rowlett, so a mixed job stays on one purchase order and one certification package instead of moving between vendors.

Keep reading

Related

What CARC actually requires

The system, the specs and what the paperwork has to prove.

Read more →

Cerakote vs. anodizing vs. powder

Three very different tools. How to pick between them.

Read more →

Masking: what to call out

How to mark up a print so critical surfaces stay clean.

Read more →

MIL-spec cross-reference

The primers, topcoats and pretreatments, grouped and explained.

Read more →

Common questions

Frequently asked questions

Is powder coating always more durable than paint?

Generally yes on impact and abrasion, because the film is thicker and cross-linked. But a properly specified multi-layer liquid system can outperform powder on chemical resistance and on very specific requirements like chemical agent resistance. Durability is measured against your environment, not in the abstract.

Can you powder coat aluminium?

Yes, routinely, with appropriate pretreatment. The substrate is rarely the limiting factor — heat sensitivity of the assembly and the specification are.

What temperature does powder coating cure at?

Typical cure schedules run in the range of 350–400°F for roughly 10–20 minutes at metal temperature, depending on the powder chemistry. If your part cannot see that, liquid is the answer.

Can you apply powder over a MIL-spec pretreatment?

Yes. Chemical conversion coating per MIL-DTL-5541 followed by powder is a common combination where the drawing permits it.

Which one is cheaper?

Powder is usually cheaper per square foot at volume. On very small quantities, on parts requiring extensive masking, or where a multi-coat liquid system is specified, the gap narrows or reverses.

Can you do both on the same job?

Yes. We run powder, liquid, Cerakote and silk screening in the same facility, so mixed-process jobs ship from one supplier under one quality system.

Ready when you are

Not sure which one your part needs?

Send the print and the requirement. We will tell you which process fits — including when the answer is the one we would rather not quote.