Powder Coating vs. Wet Paint in Aerospace Machining

Throughout most of the aerospace industry, the standard coating for parts is wet paint over a layer of primer. Powder coating is seldom used, though it is common in other industries that rely on precision machining such as the automotive industry. 

As experts in aerospace and defense manufacturing, Alard Engineering has recognized opportunities to use powder coating in aerospace machining, especially for parts that must maintain flexibility or withstand significant environmental stress. 

But first, here’s a quick refresher on each term: 

• Wet paint is a liquid that is applied to a surface using a spray, pump, or pressurized device. Multiple coats may be required to achieve an even finish.

• Powder coating begins as a free-flowing, dry powder before being applied to a surface electrostatically and cured via heat or ultraviolet light. The end result is a hard finish that is more durable than wet paint. 

Choosing between Powder Coating or Wet Paint for Aerospace Parts 

The costs and lead times for each type of coating are similar, but there are other factors to consider when choosing a coating for your aerospace parts: 

Flexibility

Post-priming, wet paint is sprayed onto parts and left to cure. Once the paint cures, it’s inflexible, meaning that the paint will crack and chip if the part is bent. 

Powder coating, however, is already dry when applied. It still needs to cure, but it remains flexible afterward, so the part can bend or flex without cracking or losing any coating. 

Environmental conditions 

A wet paint coating can become damaged when exposed to certain environments. If a painted part will be outdoors in its end-use application, for example, the paint may chip over time, allowing the part to rust. 

In contrast, powder coated parts are less likely to chip or rust. If your aerospace part will be outdoors or exposed to extreme environmental conditions, powder coating may help slow wear and tear.

Color matching

One drawback of powder coating is that it’s more difficult to color match than wet paint. Compare a section of a part that was touched up with powder coating to the original powder coat, and you may be able to spot a clear difference. 

With wet paint, on the other hand, touch-ups can appear seamless. 

Materials

Wet paint and powder coating both work on virtually any metal material, including standard aerospace materials like steel, aluminum, and stainless steel. 

For plastic parts, additional processes may be required to get the coating to adhere, but these processes are similar for both types of coating.

Tolerance requirements

Holding precise tolerances can be challenging when using wet paint or powder coating. Ideally, blueprints for powder coated or painted parts should specify the part’s dimensions before a coating is applied and, if necessary, include clear instructions about the number of coats required. 

If a part has a specific tolerance that must be maintained after wet paint or powder coating, let us know. We can calculate the amount of thickness that a finishing method will add to the part and adjust our precision machining approach if needed to ensure that the dimensional tolerance matches the blueprint after the coating is applied. 

Choose Alard Engineering for Aerospace Machining 

No matter which finishing option you choose, Alard Engineering can support you. 

Our experienced team members are happy to work with you to determine the optimal coating for your aerospace parts and coordinate getting your parts either painted or powder coated. 

While we have traditionally relied on trusted finishing vendors to provide these services, we are thrilled to share that we recently developed a strategic partnership with Applied Powdercoat Inc. in Oxnard, CA to streamline powder coating projects even further.

Request a quote to work with us!