The Blackening Process: Ultra-Blak 455
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 (passive surfaces only)
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 163 is a non-caustic and non-silicated phosphate cleaner for zamac alloys. It's a 7-step process.
- E-Kleen 153 allows users to soak clean or electro clean metal parts with a single product. It's part of a 7-step process.
*Note that the blackening process for Ultra-Blak 455 varies depending on whether the cadmium or zinc surface is passive or freshly plated. If the metal is freshly plated, rinse the parts, neutralize any residual contaminants with nitric acid (0.5% by volume), rinse again, and begin with the blackening step. If the metal is passive, the parts will need to be cleaned, rinsed, activated, and rinsed again.
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. Activation (passive surfaces only)
Immerse the passive parts in a nitric-acid or sulfuric-acid solution (both 2–5% by volume) for 10–60 seconds.
Rinse in cold, overflowing tap water for 30–60 seconds.
Immerse the still-wet parts in a solution of Ultra-Blak 455 at 130–160º F until a deep black color develops. Immersion time will be approximately 1–10 minutes, depending on the surface condition of the parts.
If Ultra-Blak 455 isn't quite what you’re looking for, consider these similar products:
- Ultra-Blak 460 is a 160º F blackening process that is chrome free.
- Insta-Blak Z-360 is an easy-to-use, quick-finish room temperature blackening process.
Rinse in cold, overflowing tap water for 30–60 seconds to remove residual blackening solution and ensure sealant will not be contaminated.
Seal the black-oxide finish by immersing the still-wet parts in a corrosion-inhibiting, rust-preventative, and water-displacing 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 510 is a non-solvent, water-soluble oil that results in a slightly oily finish.
- E-Laq 525 provides a hard, dry, and corrosion-resistant finish.
- E-Tec 504 is a solvent-based, water-displacing oil.