Take control of heat coloring your metal art

Heat Coloring Steel

5 Essentials for Mastering the Art

Why Choose Heat Colors to Patina Your Steel Art?

With so many ways for artists to add color on metal, why use heat colors?

Unlike paint, whose primary purpose may be protecting the surface from the elements, when we choose patinas for metal art, we typically want to change the color of the metal without obscuring its innate character.

One of the beauties of heat coloring is how it colors metal while retaining its dynamic, reflective qualities.

But, as attractive as heat colors are, many artists struggle to apply them with consistent results.

I’ve identified five vital elements for your overall success when using heat colors to patina your metal art.

With each dialed in, you can harness their spontaneity, beauty, and character to bring your heat-colored artwork to life.

These five elements are:

  • Your Workspace
  • Your Heat Source
  • Your Technique
  • Your Approach
  • and Your Ingenuity
In this creative-edge metal wall art print of my layered steel and wood heat-colored steel engraving, a happily breaching humpback whale interrupts a seagull's evening meal.
Unexpected Company is metal and wood wall art made with layers of heat-colored steel and decorative grinding.
Wood and metal wall art of a native hunter watching at a seal's breathing hole in front of a rising seal moon. Created when Yukon Kuskokwim Health Corp. decided to commission art for the new health center in Bethel, AK.
Whatever your artistic style, heat colors may be the perfect complement.

The Heat Color Spectrum

While heating steel initiates a chemical reaction between iron and oxygen, creating a thin oxide layer on the metal, the thickness of the layer determines the resulting colors.

Here you can see the rainbow gradient of colors of metal achieved by heating steel with a torch.

Heat colors develop in a narrow 400ºF to 700ºF range. As you’ll see in the heat color temperature chart further down the page, only a few degrees separate each color, making it even trickier to stop heating at just the right color.

Learning to control the temperature in any given part of the workpiece will help you achieve your desired result.

Although you can do it almost anywhere, setting up your heat coloring workspace for optimal results will directly influence how easily you can get the colors you’re after.

Similarly, choosing the right heat source and learning the best technique for the job at hand can make the difference between frustration and success. 

A happily breaching humpback whale interrupts a seagull's evening meal in this layered heat colored steel and wood relief.

You can color your metal art using heat by applying specific heat colors in distinct, isolated areas or across broader sections as colorful gradients.

You’ll see a hint of light straw when the colors begin to run. Then, the color gradually darkens as the temperature rises, transitioning to orange-red and purple.

Next comes dark blue, light blue, and light grey green. If you continue to heat, you’ll notice the colors run again in more pastel shades before turning to dark green and, ultimately, fire-scale gray.

Though a degree is a degree, factors besides temperature come into play when heat coloring steel.

The surface to be colored, your heat coloring technique and the work environment affect the resulting heat colors.

Learning to adapt your technique to any given piece goes a long way toward creating the effects you’re after in your metal art.

Take Control of Heat Coloring Your Metal Art

In my 90-minute online workshop, Heat Coloring Essentials – Taking Control of Heat Coloring Your Metal Art, I share exactly how to get consistent results with heat-coloring steel.

The workshop covers the essential factors necessary for mastering the art of heat coloring.

The Heat Color Spectrum
– What heat colors are
– Your heat color palette
– How do heat colors set themselves apart from other patinas?

Your Workspace
– Important safety considerations
– Optimal workstation design
– Lighting considerations for best results
– Workpiece support configuration

Your Heat Source
– Choosing the Right Torch
– Choosing the right fuel
– Torch Size vs. Workpiece Size

Your Technique
– Factors that affect the result
– Torch pattern basics
– Adapting your technique to unique shapes and special situations

I’m already using heat coloring, but always ready to learn more.
Coloring the ocean with a large propane torch. For larger piecs of thinner steel, I do the coloring from one side to the other rather than with a uniform even heat on the whole piece.
Pat G.
Metal Sculptor and Blacksmith
I do metal art with painting only have not tried heat coloring yet but would love to learn. I have a plasma table so I cut out all sorts of things from sheets of flat steel mostly 26 gauge. It looks like it is something that I could incorporate with what I'm cutting out with my plasma table
Coloring the ocean with a large propane torch. For larger piecs of thinner steel, I do the coloring from one side to the other rather than with a uniform even heat on the whole piece.
Bruce P.
Metal Artist

Subtleties of Color

From adding a splash of color to your metal art to creating sophisticated metalwork paintings on sheet steel, heat colors offer a broad range of brilliant or subtle colors to your artistic palette.

Though heat colors are beautiful in their own right, they really come to life when you combine them with variations in the inherent color of steel as light reflects from the surface of decorative grind patterns.

A painter can model forms and suggest subtle variations of color found in nature by mixing different values of color.

In heat-colored steel engraving, the metal artist uses decorative metal grinding to create subtle variations in the reflected light and, in turn, variations of color value and the suggestion of form, motion, transparency, and material.

I teach the entire process of making heat-colored steel engravings in my signature online course, The Art of Heat Colored Steel Engraving.

And f you’re particularly interested in decorative grinding, I’ve dedicated an entire module to it.

Functional Uses for Heat Colors

Artists and craftspeople have used heat colors since time immemorial.

If you’ve worked with steel, you’ve seen them appear as you weld. And if you’ve held a tool to the grindstone a bit too long, you’ve discovered the hard way just what that blue color can mean.

As I learned from Alexander Weyger’s book ‘The Making of Tools,’ blacksmiths, toolmakers, and bladesmiths have long used heat colors, or temper colors to gauge the hardness of steel during the heat-treating process.

Each color in the heat color spectrum corresponds with a specific temperature and hardness.

Blue for springiness, straw for woodcarving chisels, etc. When you temper a tool, watching the colors run on the bare steel provides the necessary cue for quenching the tool for a specific end purpose.

I’d made a good many wood and stone carving tools before I ever considered heat colors as a patina for artwork. 

But that’s another story

When it comes to changing the color of metal, heat coloring is one of the more ‘natural’ methods, as it doesn’t require additional chemicals, pigments, or coloring agents.

Coloring steel with heat is a pretty simple process. However, there are a few things to keep in mind to achieve consistent results. 

I’ve used heat colors to patina my steel wall art since the early ’90s. 

Over years of trial and error, I’ve honed in on the essential elements that have helped me get repeatable results with each heat color, from light straw to dark green and all the colors in between.

Whether you’re tempering a tool or adding the finishing touch to your latest metal sculpture, mastering these essential elements will help alleviate some of the common frustrations you may have experienced when heat coloring so you can get on with your creative process.

If you have a couple of hours and want to take control of heat coloring to get consistent results and predictable colors, check out my online heat coloring workshop, Heat Coloring Essentials – Taking Control of Heat Coloring Your Metal Art.

Factors to Consider When Coloring Steel With Heat

Ensure You're Working in a Safe Environment

Basic shop safety is beyond this article’s scope, and you should always familiarize yourself with acceptable safety practices and follow the instructions for using your equipment.

Before you begin, be sure the work area is free from flammable materials and tripping hazards.

And be sure you have a working fire extinguisher at the ready.

Familiarize Yourself with the Heat Color Temperature Chart

Though it’s not necessary to know what temperature each color appears at, you can see from this chart that only a few degrees separate the various heat colors.

A heat color temperature chart is a handy reference but actual temperature values don’t really come into play when you’re coloring your artwork.

Unless of course, you use a heat treating oven. In the absence of a suitably sized oven, the tool of choice for heat coloring is a torch.

With an oven, you can let the metal soak long enough to achieve a uniform temperature, though soaking time will also come into play. With a torch, the challenge of creating an even heat throughout the workpiece is in your hands.

Use a torch sized for the work piece.

This example of heat coloring steel shows the process of coloring the ocean layer of piece of multi-layer metal wall art with the heat from a large propane torch. For larger piecs of thinner steel, I do the coloring from one side to the other rather than with a uniform even heat on the whole piece.
A large propane weed burner is an excellent all-around heat coloring torch

When you are heat coloring steel and want to achieve an even color across the entire piece, it’s best to create an oven-like environment.

Trying to heat a large piece of steel with too small a heat source can be futile. Your torch needs to provide enough BTUs to keep the steel from cooling in one area while you are heating another.

But even with a suitably sized torch, you must pace yourself, giving the heat time to soak the steel thoroughly.

Pay Attention to Your Torch Pattern

An irregular torch pattern can make it difficult to achieve an even heat. The shape of your steel also comes into play when heat coloring.

For example, when coloring an unevenly shaped piece of steel, you’ll need to adapt the torch pattern to accommodate projections that may heat and cool more quickly.

Nonetheless, when the first straw color appears, you’ll have a visual reference for adjusting your torch pattern to account for any hot or cold spots.

Though it’s a speedy timelapse, the following video illustrates my typical torch pattern.

Patience is Everything

Take your time as you ease up to the desired color. Heating too fast is one of the most common mistakes artists tend to make. And, practice, practice, practice.  Scrap steel is your friend. Grind it to bare metal, pick up your torch, and color it. There’s a lot to learn.

 I’ve been making heat-colored steel metal art for nearly thirty years and am still developing and refining my techniques for heat-coloring steel.

If you’d like to avoid learning by trial and error and quickly learn to take control of heat coloring, take a look at my online heat coloring workshop.

I detail the essential factors for achieving success with heat coloring so you can get beyond the struggle and focus on your creative process.

"My biggest single problem is consistency and control of color."

I have several years experience with CNC cut artwork and heat coloring as primary decorative accent. – Biggest single problem is consistency and control of color.

Coloring the ocean with a large propane torch. For larger piecs of thinner steel, I do the coloring from one side to the other rather than with a uniform even heat on the whole piece.

Not ready for a workshop? If you’d like inspiration and information about heat coloring, decorative grinding, and my metal art process, subscribe to my metal art newsletter.

Learn how to make heat-colored steel engravings in your artistic style?

Although my workshop covers everything you need to get consistent results with heat colors, my signature metal art course may be for you if you want to learn the entire process of making heat-colored steel engravings.

Every medium has its workflow

Just as your inspiration for learning new skills holds you to the course throughout the learning process, your vision for each finished piece guides your every action during the creative process.

Unlike working with many mediums, heat-colored steel engraving is a process of finish-it-as-you-go. Because you have to texture and color areas of your design sequentially, working from hot to cold, you develop all-new ways of reconciling the current stage of progress with your vision of the finished piece.

Each section you complete reinforces, clarifies, or alters that intention. And when you add the final silver highlight, you are greeted with what will likely be a combination of familiarity, surprise, and wonder.

I cover every detail of this metal art process in my metal art course, The Art of Heat Colored Steel Engraving.

Not ready for a workshop or course right now? If you’d like inspiration and information about heat coloring, decorative grinding, and my metal art process, subscribe to my metal art newsletter.

In Conclusion

Heat coloring may be a perfect choice if you’re looking for ways to enhance the color of metal, whether for artwork or industrial uses.

It takes some time to master, but the rewards are many.

One of the things I love so much about heat coloring steel is that no matter how skilled you become at achieving a particular effect, there are always variables beyond your control that may enhance your work.

The wind and the weather when heating, the degree of surface cleanliness, imperfections in the steel, variations in surface texture, compensating for hotter and colder spots in contact with the support, and uneven heating are just a few of the things that can influence the way the heat colors ‘take.’

It takes patience to learn to mitigate those you can’t live with and on-the-spot decision-making to embrace those that further your artistic vision.

The more proficient you become with controlling your torch and applying heat colors to your metal art, the more you can focus on the creative process and what inspired you to make your art.

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