6 Tips for Designing Powder Coated Sheet Metal Parts (Updated for 2024)

Last updated on January 31st, 2024 at 09:53 am

At Approved Sheet Metal, we deliver excellence in sheet metal fabrication. And providing you with the highest-quality service includes helping you choose the best finishing method for your parts.

Powder coated sheet metal parts are durable, attractive, and the method is versatile which works well for many applications. In our shop, we powder coat aluminum, steel, and stainless steel parts with fantastic results.

With over two decades of experience in powder coating, we’ve learned that a little bit of foresight yields superior outcomes. Here are our top tips for powder coated sheet metal parts.

1. Make Sure Your Part Can “Hang”

When we powder coat your parts, we hang them on a rack, ensuring that all surfaces are exposed to allow for a uniform coat. There are a few different ways to prepare parts for hanging:

Existing holes

Many parts come to us with holes already drilled for hardware insertion. We can use the same holes to hang the parts for powder coating.

New holes

If your part requires powder coating and your design doesn’t already have holes, we recommend designing a 0.125″ diameter hole in an inconspicuous area so that we can hang your part.

Break-off tabs or clips

It’s important to note that any holes added to a part won’t be plugged after powder coating. If a small but permanent hole isn’t an option, you can add break-off tabs with holes that can be removed after powder coating. Alternatively, if your part is small (6″-8″), it can hang from clips attached to the rack.

But keep in mind that with either of these approaches, some final touch-up will be required, which may increase your costs.

2. Account for Buildup

Powder coating adds approximately 0.003″-0.004″ of buildup to a part, and it’s important to account for this buildup in your design.

Designs with tight hole tolerances, in particular, may require post-powder coating operations to open up the holes.

3. Clarify Specific Colors, Textures, and Sheens

The wide variety of powder coat options is one reason it’s such a popular finishing method. But the same color一even something as seemingly straightforward as “powder coat black”一can vary considerably among powder coat brands.

Calling out the exact RAL (color code), texture, and gloss for a specific brand is the

best way to ensure that your part will have the final appearance you desire. Note that although a RAL describes a unique color, the color may still vary slightly from one brand to another.

It’s also important to remember that if you’ve used a powder coat from a particular brand for your prototype, you should use the same powder coat during production to ensure consistency.

Finally, keep in mind that not all powder coat varieties are readily available, and some may have a high per-pound cost with a minimum buy that exceeds your needs. You may want to compare the availability and cost of a few types before making your final decision.

Locating color information

So, where can you find specific color information to share with your finisher?

Browsing color palettes on the websites of suppliers such as Cardinal Paint and Sherwin-Williams is a great way to start. Be aware, however, that colors may appear different online than in real life. To verify that you’re choosing the right color for your powder coated sheet metal parts, request physical samples from the supplier.

We are also happy to send samples of our house colors for your review. Complete our contact form for details!

4. Request Pre-Treatments When Needed

Treating parts with chromate or zinc before powder coating provides enhanced corrosion resistance, which may be necessary for parts that will be used in harsh environments or require electrical conductivity.

These treatments are added only upon request, so be sure to call them out if needed.

5. Insert Hardware after Finishing

Many types of hardware, such as panel fasteners and quarter-turn hardware, won’t perform properly when added before powder coating. If you’re wondering whether a hardware component should be added before or after finishing, our team is happy to advise you.

6. Select a Single Color

While applying multiple colors of powder coat to a single part is technically possible, doing so can be needlessly difficult, risky, and expensive. For example, the part can become scorched or incur unwanted paint residue from masking.

If you need a multi-colored part, wet paint is a preferable choice.

Why Choose Approved Sheet Metal for Powder Coated Sheet Metal Parts?

At Approved Sheet Metal, we provide sheet metal fabrication services and powder coating services under one roof, giving us full control of the entire manufacturing process and ensuring that you get high-quality parts quickly and cost-effectively. In fact, our in-house powder coating services save you about three days in lead time!

With robust capabilities for sheet metal finishing, we can fulfill your powder coating needs. Request a quote!

Recommended Default Sheet Metal Tolerances

DIM	Tolerance (MM)	Tolerance (Inches)	Description
A	± 0.13	± 0.005	Sheared Edge to Hole
B	± 0.13	± 0.005	2 Holes on One Surface
C	± 0.25	± 0.010	Formed Edge to Hole
D*	± 0.76	± 0.030	Holes Across 2 Bends
E*	± 0.76	± 0.030	Holes Across 4 Bends
F	± 0.25	± 0.010	Sheared Edge to Bend
G	± 0.38	± 0.015	Across 2 Bends
H*	± 0.76	± 0.030	Formed Part

Noted dimensions are to be taken while the part is in a restrained condition. Noted dimensions are for parts within a 12″ envelope.
* Dimensions D, E and H are not recommended forms of dimensioning
These tolerances are recommended and best practices. We can obtain tighter tolerances (depending on part geometry/ construction), contact us for more information Download PDF

Powder Coated Sheet Metal FAQ

What materials can you powder coat, and what are the benefits of powder coating?

At Approved Sheet Metal, we can powder coat aluminum, steel, and stainless steel parts. Powder coating offers durability, attractiveness, and versatility, making it suitable for various applications. It provides a protective and visually appealing finish to your parts.

How can I prepare my parts for powder coating?

To prepare your parts for powder coating, you should ensure they can be hung on a rack for uniform coating. This can be achieved through existing holes, new holes, or break-off tabs or clips. Existing holes or designed holes (0.125″ diameter) are common options, while break-off tabs and clips are suitable for smaller parts. Keep in mind that adding holes may require touch-up work, affecting costs.

How does powder coating affect part dimensions, and how can I specify colors and textures?

Powder coating typically adds 0.003″ to 0.004″ of buildup to a part, which may impact tight hole tolerances. To specify colors and textures accurately, provide the exact RAL (color code), texture, and gloss from a specific brand. Remember that colors may vary slightly between brands. Consistency is key; use the same powder coat brand for production as for the prototype. Consider the availability and cost of powder coat types.

When should I request pre-treatments before powder coating?

Pre-treatments like chromate or zinc are necessary for enhanced corrosion resistance in harsh environments or when electrical conductivity is required. These treatments are added upon request, so be sure to specify if needed to ensure the best results for your parts.

Can hardware be added before or after powder coating?

In most cases, hardware should be added after powder coating to ensure proper functionality. Certain types of hardware, such as panel fasteners and quarter-turn hardware, may not perform correctly if added before finishing. Our team can provide guidance on the appropriate timing for adding hardware.