The Blackening Process: Insta-Blak A-380
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 102 provides a heavy etch and requires de-smutting.
- E-Kleen 163 provides a mild etch and removes less aluminum than other cleaners.
- E-Kleen 154 is for extrusions without silica. It allows users to clean and/or de-smut in one step (eliminating steps 2 and 3), saving time and money.
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. Deoxidize (for extrusions and wrought alloys)
Immerse parts in a solution of E-Pik 210 for 5 minutes or in a solution of nitric acid (40% by volume) for 1–5 minutes.
4. Rinse
Rinse in cold, overflowing tap water for 30–60 seconds to remove residual blackening solution and ensure subsequent steps will not be contaminated.
5. Blacken
Immerse parts in a solution of Insta-Blak A-380 (25% by volume) until a deep black color develops, approximately 30–120 seconds. The solution must be kept below 85° F. If possible, blacken small parts in rotating perforated barrels. Dip baskets will also work, but parts must be agitated when first introduced to the solution.
If Insta-Blak A-380 isn't quite what you’re looking for, consider these similar products:
- Insta-Blak A-385 is an easy-to-use, room-temperature blackening solution with an acid-selenium base, which produces some smut.
6. Rinse
Rinse in cold, overflowing tap water for 30–60 seconds to remove residual blackening solution and ensure sealant will not be contaminated.
7. 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-Laq 525 is a water-based lacquer that results in a hard, dry, and glossy finish.
- E-Tec 521 is a glossy, wax-dry finish that offers extra lubrication.
- E-Tec 504 is a solvent rust preventive that produces a thin film with a dry finish.
