The Blackening Process: Ultra-Blak 400
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.
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. Clean the parts for about five minutes prior to beginning the blackening process.
Recommended Cleaning Products:
- E-Kleen SR 196 is a silicated, non-emulsifying soak cleaner for that floats oil and eliminates carbon smut and other soils.
- E-Kleen SR 102-E is a non-silicated liquid soak cleaner that emulsifies soils and oils.
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. Pickle (optional)
Run the freshly rinsed part through an acid-salt pickle of E-Pik 211 or hydrochloric acid (50% by volume).
Following the pickle step, thoroughly rinse the parts with water before blackening
Immerse the steel part in a boiling solution of Ultra-Blak 400. Immerse the part for 5–20 minutes, depending on the size/mass of part and the depth of black desired. See the technical data sheet for specifics on time, temperature, and solution makeup.
If Ultra-Blak 400 isn't quite what you’re looking for, consider these similar products:
- Kool-Blak 225 is a mid-temperature black-oxide solution that gives steel parts glossy black finishes while eliminating the hazards of caustic fumes and boiling temperatures.
- Ultra-Blak 400-L is the liquid counterpart of Ultra-Blak 400. It produces one of the deepest black finishes possible and is ideal for users who want a safer method of replenishing the blackening solution.
Rinse in cold, overflowing tap water for 30–60 seconds to remove residual blackening solution and ensure sealant will not be contaminated. Transfer the metal parts from the blackening solution to the cold-water rinse as quickly as possible to avoid discoloration.
Seal the black-oxide finish by immersing the still-wet parts in a 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.
See the rust preventative and sealing comparison chart to find the best E-Tec solution for your needs.
Recommended Sealing Products:
- E-Tec 501 produces an oily finish and helps inhibit rust and corrosion.
- E-Tec 505+ is a long-lasting dry, soft-film lubricant and rust/corrosion inhibitor that's specifically formulated for hot black oxide lines.
- E-Tec 520 is used to deposit a corrosion-inhibiting, hard, clear, glossy, and dry finish.