Electrocleaning solutions
Supplied electrocleaner formulations, substrate-specific polarity claims, ingredient disclosures, and the limits of comparative property data.
Tags: chemicals, cleaning, surface-finishing
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Identity and process role
Hubbard-Hall’s E 159 powder SDS gives pH 14 without a test-solution concentration. Its E 9091 TDS gives pH 12.5–13.0 at the stated 4 oz/Gal test concentration. Neither establishes a bath setpoint. EPi separately identifies E-Kleen SR 1021 as an additive. EPi product description Aquaease E 159 bulletin
Cathodic cleaning makes the workpiece negative. Anodic cleaning makes it positive. Periodic reverse alternates those roles. Gateros Plating cleaning support, alkaline-cleaning section, undated
The EPA and NEWMOA's historical reference describes oxygen evolution at the anodic workpiece and hydrogen evolution at the cathodic workpiece. Gas action assists soil removal. Its discussion also identifies cathodic contamination and hydrogen-embrittlement concerns. These mechanisms do not establish a universally suitable polarity or a hydrogen-safe process. EPA/742/B-97/005, February 1997, chapter 5, pages 48-49.
Electrocleaning is a preparation operation, distinct from depositing a metal coating. Gold Plating Services places its Electro-Cleaner Solution before activation and electroplating. Its SDS's intended-use label, "Electroplating bath and brush," therefore does not identify a metal-depositing electrolyte. Cleaning also does not establish etching or passivation capability. Electro-Cleaner TDS 2024, Electro-Cleaner SDS, sections 1 and 16.
Product claims depend on the substrate
The following are product-specific descriptions, not interchangeable approvals or operating conditions.
| Supplied product and source identity | Documented application and polarity boundary |
|---|---|
| Hubbard-Hall Aquaease E 159, code 2001002. Bulletin revised January 4, 2024 | Alkaline powder for steel, cast iron, copper, copper-plated work, nickel-plated work, and stainless steel. The general description permits cathodic, anodic, and periodic reverse use. Its substrate tables distinguish anodic cleaning of steel and copper from cathodic cleaning of nickel-plated work, stainless steels, and high-carbon cast irons. E 159 bulletin, pages 1-2. |
| Hubbard-Hall Aquaease E 9091, code 2001007. Bulletin revised May 15, 2025 | Alkaline granular powder developed for nonferrous metals, with ferrous use also stated. Zinc die castings have an anodic entry. The combined brass, copper, lead-alloy, and white-metal table lists either polarity. Its footnote qualifies cathodic copper and brass use with follow-on treatment where possible. It specifically assigns cathodic cleaning to lead alloys, pewter, white metals, and slush castings. The broader table heading cannot erase these qualifications. E 9091 bulletin, pages 1-2. |
| EPi E-Kleen SR 1021, SDS code EPI-0236C. Family TDS dated December 26, 2024 | Liquid desmutting additive for steel and iron. The SR 1020, SR 1021, and SR 1022 family table identifies SR 1021 as silicate-containing, without chelator, and anodic. This is an explicit supplier claim, not an inference from an SDS ingredient list. Family TDS, pages 1-3. |
| Gold Plating Services Electro-Cleaner Solution. Web TDS titled 2024 | Alkaline liquid for bath and brush cleaning of residual oils and dirt. The TDS excludes label residue, polishing compounds, and lacquers from its removal claim. This source does not explicitly name a cathodic or anodic mode for the workpiece. Electro-Cleaner TDS. |
E 159 has conflicting compatibility language. Its TDS includes copper and steel, while its older SDS describes corrosivity toward copper and most alloys containing it, including brass and bronze. A separate SDS statement conditions steel corrosivity on elevated temperature. Aluminum, tin, and zinc are also incompatible. Different document purposes and unspecified exposures prevent a blanket alloy-safety conclusion. E 159 SDS, revised March 19, 2021, section 10.
E 9091 has a related scope distinction. Despite its zinc-die-casting application, the SDS cautions against contact with zinc, aluminum, tin, and their alloys when handling the product. The supplied powder and its intended cleaning solution cannot share an unqualified compatibility claim. E 9091 SDS, revised March 19, 2021, section 10.
Ingredients and formulation functions
Builders provide the alkaline base of many aqueous cleaners. Surfactants reduce surface tension, chelants retain metal ions in solution, and sequestering agents capture hardness ions. Inhibitors can reduce attack on sensitive metals, but may also complicate residue removal and subsequent plating. These are ingredient-class functions, not proof that every electrocleaner contains each class or achieves each benefit. EPA/NEWMOA, February 1997, chapter 5, pages 45-46.
Selected disclosures identify supplied products, not working-bath compositions. They are not complete formulation specifications.
| Product SDS | Disclosed ingredients and percentage basis |
|---|---|
| E 159, March 19, 2021, section 3 | Sodium hydroxide, CAS 1310-73-2, approximately 45%; sodium metasilicate, CAS 6834-92-0, approximately 27%; sodium carbonate, CAS 497-19-8, approximately 15%; tetrasodium pyrophosphate, CAS 7722-88-5, approximately 5%. The column says concentration percent without specifying mass or volume. E 159 SDS. |
| E 9091, March 19, 2021, section 3 | Sodium carbonate, CAS 497-19-8, approximately 45%; sodium metasilicate, CAS 6834-92-0, approximately 20%; tribasic sodium phosphate, CAS 10101-89-0, approximately 3%; sodium hydroxide, CAS 1310-73-2, approximately 20%; tetrasodium pyrophosphate, CAS 7722-88-5, approximately 8%. The percent denominator is unspecified. E 9091 SDS. |
| SR 1021, April 7, 2022, revision 1, section 3 | Water, CAS 7732-18-5, 75-85 weight%; sodium silicate, CAS 1344-09-8, 10-20 weight%; ethoxylated coconut oil alkyl amine, CAS withheld, 0.5-1 weight%. Exact concentrations are trade secrets. SR 1021 SDS. |
| Electro-Cleaner Solution, October 15, 2024, section 3 | Demineralized water, CAS 7732-18-5, 96.9%; disodium carbonate, CAS 497-19-8, 2.3%; sodium hydroxide, CAS 1310-73-2, 0.8%. The percentage heading does not declare a mass or volume denominator. Gold Plating Services SDS. |
Synthesis from these disclosures supports different supplied forms and chemical identities. It does not identify every component's proprietary function. Sodium silicate and sodium metasilicate are separately named substances with different CAS identifiers here. Missing SDS entries do not prove absence of metals, halogens, surfactants, inhibitors, or chelants. Supplier statements about silicate or chelator content remain specific to the named variant and document.
Properties require a sample and measurement basis
| Product and source | Reported property | Measurement limit |
|---|---|---|
| E 159 SDS, section 9 | pH 14; complete water solubility; relative density marked N/A | Powder pH lacks a stated aqueous test concentration and temperature. This is not a pH for a dry solid or a working-bath target. E 159 SDS. |
| E 9091 TDS, page 1 | pH 12.5-13.0 at 4 oz/Gal | This is a specified test solution, not the supplied powder. The physical-data entry does not state test temperature or define the gallon and ounce conventions. E 9091 bulletin. |
| SR 1021 SDS, section 9 | pH 10.93-11.93; relative density 1.1045-1.1095; complete water solubility | No test concentration, temperature, or density reference basis is given. These are supplied-product SDS data, not properties of the separately formulated cleaner bath. SR 1021 SDS. |
| Electro-Cleaner Solution SDS, section 9 | Specific gravity 1.05; complete water solubility; pH and density marked unavailable | Specific gravity has no stated sample temperature or water-reference temperature. It cannot supply the missing measured density without additional assumptions. Gold Plating Services SDS. |
E 9091's SDS repeats pH 12.5-13.0 without the TDS's test-solution basis. Its relative density is N/A. The SDS alone therefore does not define that measurement context. E 9091 SDS, section 9.
Dimensional synthesis explains why these values do not form a performance ranking. pH is dimensionless and depends on the aqueous sample. Relative density and specific gravity are ratios; density has mass-per-volume units. Conductivity requires units such as mS/cm and a sample temperature. E 159's qualitative high-conductivity claim supplies neither a numeric value nor a matched comparison test. E 159 bulletin, page 1.
The cited sources provide no common comparative solids, active-content, or free-alkalinity or total-alkalinity specification. Those quantities have different meanings and denominators. A sum of SDS percentages is not a measured solids result, and pH alone does not establish alkali reserve. The EPi family TDS distinguishes free and total alkalinity in its analytical discussion, without making either a supplied-product solids specification. EPi family TDS, page 3.
Standards and evidence limits
ISO 27831-1:2008 addresses cleaning and preparation of ferrous surfaces. ISO 27831-2:2008 addresses nonferrous surfaces. Both are edition 1, published October 2008 and confirmed in 2024. Their public scopes distinguish preparation from subsequent coatings and exclude preliminary removal of heavy service deposits, preparation for welding, and cleaning electrical contacts. These scope statements do not qualify a proprietary cleaner or establish acceptance criteria. ISO 27831-1 public abstract, ISO 27831-2 public abstract.
This reference covers the identified English-language supplier documents. Regional equivalents, later reformulations, lot properties, and independent performance comparisons remain unverified. Gold Plating Services' linked SDS has a 2026 filename but prints October 15, 2024 as its preparation date. The printed date is the document identity used here. The EPA manual supplies historical process context, not current regulatory acceptance.
Soil removal, foam behavior, wetting, and substrate compatibility are separate claims. None of the cited product names or ingredient disclosures proves universal alloy compatibility, freedom from hydrogen embrittlement, adhesion, deposit quality, customer approval, or environmental acceptance. The supplied-product reference does not define a production recipe or establish the composition and condition of a used bath.
Related reference
Surface-finishing processes covers the relationship between preparation, coating, and final surface requirements.