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Ultra-Blak 407

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A versatile blackening solution used to blacken stainless steel alloys 200, 300, 400, and 17-4 Ph, malleable cast iron, and mild, low-carbon steels.

Ultra-Blak 407 produces a black finish that does not change the dimensions of the item and offers superior abrasion resistance. Requires ventilation, a seven-stage blackening line, and boiling chemistry. Meets military specification MIL-DTL-13924D, Class 4.


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How to Use Ultra-Blak 407

Ultra-Blak 407 may be used to blacken stainless steel parts that require extra abrasion resistance and dimensional stability. The powder may also be used on malleable cast irons and some mild low-carbon steels.

Use Ultra-Blak 407 to:
  • Blacken stainless steel surfaces
  • Maintain an item's dimensions and structure
  • Achieve superior abrasion resistance
  • Work with a powder rather than a liquid
  • Meet MIL-DTL-13924D Class 4 standards

Guides & Manuals

Safety & Technical Data

The Blackening Process: Ultra-Blak 407

For the longest-lasting, deepest, and cleanest black finishes, we recommend the following blackening process. Please read all safety data sheets and technical data sheets prior to beginning a project.

1. Clean

Soils such as cutting oils, coolants, lubricants, and rust inhibitors must be removed from the metal workpiece. Soils can inhibit the blackening process and negatively affect coating adhesion and appearance. Thoroughly clean and degrease the parts prior to beginning the blackening process.

Recommended Cleaning Products:
  • E-Kleen SR 148-E is a low-caustic formula that's ideal for removing a wide range of oils and soils.
  • E-Kleen SR 102-E is a high-caustic formula that removes difficult-to-clean metalworking fluids.
  • E-Kleen 163 works well in hand-blackening applications at room temperature. It contains no caustic and is not hazardous.

2. Rinse

After cleaning the metal parts, rinse them in cold, overflowing tap water; it’s necessary to rinse the parts to remove residual cleaning solution. Parts carrying over un-rinsed film of alkaline cleaning solution would quickly contaminate the subsequent chemicals in use, resulting in a spotty or non-adherent black finish. 

Immerse the parts to be blackened for 30–60 seconds.

3. Blacken

Immerse the parts in a boiling solution of Ultra-Blak 407 until a deep black color develops. Required immersion time may vary from 2–15 minutes, depending upon the mass, type, and surface condition of the parts. 

If Ultra-Blak 407 isn't quite what you’re looking for, consider these similar products:
  • Insta-Blak SS-370 is a room-temperature blackening process that produces no caustic fumes.
  • Ultra Blak 407-L is a liquid formula that eliminates the dust that results from the powder version, making it easier to replenish a tank.

4. Rinse

Rinse in cold, overflowing tap water for 30–60 seconds to remove residual blackening solution and ensure sealant will not be contaminated.

5. Seal

Seal the black-oxide finish by immersing the still-wet parts in a corrosion-inhibiting and rust-preventative solution. E-Tec corrosion inhibitors are formulated to rapidly displace the residual acidic solution from the preceding rinse and produce long-term corrosion protection. As the E-Tec is absorbed, it enhances the depth of black, which may take several hours.

Recommended Sealing Products:
  • E-Tec 504 is a solvent-based, dry-to-touch oil formula.
  • E-Tec 515 is a water-soluble oil that contains no VOCs. It's the most economical method for achieving corrosion protection.
  • E-Tec 522 is a water-based satin wax for lubrication properties. It provides a dry-to-touch finish.