Heat Coloring Steel

5 Essentials for Mastering the Art

Why Use Heat Colors to Patina Your Steel Art?

There are many ways for artists to add color to steel.

Unlike paint, whose main purpose may be protecting the surface from the elements, when we choose patinas for metal artwork, we intend to add color without obscuring the metal’s innate character.

This is one of the beauties of heat colors. They color the metal while retaining its dynamic, reflective qualities.

The Heat Color Spectrum

Heating steel initiates a chemical reaction between iron and oxygen that creates a thin oxide layer on the metal. The thickness of the oxide layer determines the resulting colors.

Heat colors develop in the 400º to 700º range, with the lowest temperature color being a light straw color and the hottest dark green.

You can apply specific heat colors to bare steel using a torch to control the temperature and produce the desired result.

This design aspires to convey the age-old patience of the hunter and the elusiveness of the seal. A man kneels near his kayak on a barren ice flow, patiently watching the water through a well-worn breathing hole.

Heat Colors Are Not Purely Decorative

Heat colors have been around 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. 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.

How to Color Steel With Heat

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

Whether you’re tempering a tool or adding the finishing touch to your latest metal sculpture, these pointers will help alleviate some of the common frustrations people experience when heat coloring.

What You'll Need

    • Your primary tool for heat coloring steel is a torch. The scale of your art determines its size.

 

    • Ensure you have an adequate supply of fuel appropriate to your torch so you don’t run out mid heat.

 

  • Heat-proof gloves are essential. They protect your hands while heating and allow you to grasp the hot metal should it require adjustment.

A large propane weed burner is an excellent all-around heat coloring torch.

1. Ensure You are 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.

2. Use a torch sized for the work piece.

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.

Your torch needs to provide enough heat to keep the steel from cooling in one area while you heat another.

3. Use a regular torch pattern over the entire surface.

When you are heat coloring steel, using a regular pattern as you pass the torch across the work will help you achieve an even heat. Vary the direction now and then to ensure complete coverage.

When you’re coloring an unevenly shaped piece of steel, you’ll need to to change the pattern to accommodate projections that may heat more quickly.

When the first straw color appears, adjust your heating pattern to account for any cold spots.

4. Take your time as you ease up to the desired color.

A few degrees separate the various heat colors, so proceed slowly, giving the heat time to soak the steel thoroughly.

Use each color that appears as a visual reference for the next.

5. Patience is Everything

Practice, practice, practice. Scrap steel is your friend. Grind it to bare metal and pick up your torch.

I’ve been making heat colored steel metal art since the early ’90s, and I’m still learning and refining the process of heat coloring steel.

That said, if you’re handy, you can pick up the basics pretty quickly.

And if you’re interested in learning more, I’m putting together an online course that will dive deep into the nuances of heat coloring, tools and abrasives, advanced grinding patterns, and other techniques for making heat colored steel artwork.

If the thought of making your artwork with fire, grit, and steel has piqued your interest,

Or you’d like to enrich your metal arts knowledge and practice,

My Free 5-Step Guide ‘How to Make Heat Colored Steel Engravings’ will introduce you to this unique and extraordinary medium.

And provide a framework to follow when you’re ready to give it a try.

In Conclusion

One of the things I love so much about heat coloring steel is, no matter how skilled you become at achieving an effect that conveys the character and feel of your subject; there are always variables beyond your control that may enhance the work you are doing.

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.

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