Arcdip AU 120 Autodeposition Epoxy Coating
Arcdip AU 120 is an acidic waterborne epoxy emulsion that deposits on iron and steel by chemical reaction rather than by applied current, with film building with time in the bath. There are no rectifiers, no counter electrode cells and no conversion coating stage, and Faraday cage effects do not arise.
Grade Arcdip AU 120 | Range Electrocoat | Technology Acidic waterborne epoxy emulsion, autodeposition
Technical Data Sheet
Arcdip AU 120
Issue 2026.09
1. Product description
An acidic waterborne epoxy emulsion that deposits on ferrous metal by chemical reaction rather than by applied current: the acid and the oxidiser in the bath dissolve iron at the surface, and the iron ions released destabilise the emulsion in the layer against the metal so film builds there. There are no rectifiers, no counter electrode cells and no conversion coating stage, and film builds with time in the bath, so racking is a handling question rather than an electrical one and Faraday cage effects do not arise. It deposits only on iron and steel, so mixed-metal loads and zinc-coated or aluminium parts are outside its scope.
2. Features
- Deposits chemically on ferrous metal with no applied current
- No phosphate or zirconium conversion coating stage
- No Faraday cage effect; racking is a handling question, not an electrical one
- Lower cure temperature than a conventional electrocoat bake
- Coats iron and steel only
3. Recommended uses
Coating for cold and hot rolled steel parts, castings, steel tube and stampings on lines that want to avoid a conversion coating stage and electrical racking. Mixed-metal loads and zinc-coated, aluminium or stainless parts are outside its scope.
Substrates. Cold rolled steel, hot rolled and pickled steel, castings and steel tube and stampings, cleaned and rinsed but with no phosphate or zirconium conversion coating. Zinc-coated steel, aluminium, stainless grades and plastics do not coat.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Acidic waterborne epoxy emulsion, autodeposition | Formulation |
| Supply form | Acidic waterborne epoxy emulsion for an autodeposition bath | Visual inspection |
| Bath non-volatile content | Held to the control range set for the line at commissioning | ISO 3251 |
| Bath chemistry control | Free acid, oxidiser level, redox potential and dissolved iron concentration held to the control ranges set for the line | Supplier protocol |
| Deposition behaviour | Film builds with time in the bath on wetted ferrous surfaces; zinc-coated steel, aluminium, stainless grades and plastics do not coat | Customer or supplier protocol |
| Dry film thickness, open surface | 18 to 25 µm, standard build, set by immersion time and bath control | ISO 2178 on steel |
| Cure confirmation | Passes the solvent rub count agreed for the line after the stated cure | ASTM D5402, with part temperature by attached thermocouple |
| Cross-cut adhesion | Classification 0 to 1, 1 mm cut spacing | ISO 2409 |
| Neutral salt spray, scribed panel | Duration and scribe creep limit agreed with the customer; a comparative laboratory result, not a prediction of service life | ISO 9227 exposure, assessment to ISO 4628-8 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Method | Immersion in an acidic autodeposition bath with no applied current |
| Surface preparation | Steel alkaline cleaned and rinsed, with a final demineralised water rinse before the bath and no phosphate or zirconium conversion coating; parts racked so the bath can enter and drain |
| Bath temperature and immersion time | 18 to 24 °C for 60 to 120 s |
| Rinse and seal | Water rinse, then a reaction or sealing rinse that coalesces the wet film and stops further reaction |
| Cure schedule | 100 to 120 °C part temperature for 20 to 30 min |
| Bath control | By solids, free acid, oxidiser level, redox potential and dissolved iron concentration rather than by voltage and conductivity |
Process. Immersion in an acidic autodeposition bath at 18 °C to 24 °C for 60 s to 120 s with no applied current, then a water rinse and a reaction or sealing rinse that coalesces the wet film and stops further reaction, then cure at 100 °C to 120 °C part temperature for 20 min to 30 min. Bath control is by solids, free acid, oxidiser level, redox potential and dissolved iron concentration rather than by voltage and conductivity.
6. Storage and handling
Store the emulsion in closed original containers in a cool, dry place, protected from frost and direct sunlight. Shelf life is stated on the label and Certificate of Analysis. Handle and use the product in line with its Safety Data Sheet.
7. Safety and regulatory information
Read the Safety Data Sheet before use. Safety Data Sheets and regulatory declarations are issued by our technical centre against the product and batch supplied, so they are sent on request rather than published. Request a Safety Data Sheet or declaration.
This Technical Data Sheet is published for on-screen reference. The information is given in good faith from laboratory and application experience and describes typical values; it is not a specification and does not replace a trial on your own substrate and line. Arctic Materials may revise this sheet without notice. Issue 2026.09.
Technical Data Sheets on this site are for on-screen viewing. For a controlled copy, write to tech@arcticmaterials.com.
Other grades in this range
Need a Safety Data Sheet, a regulatory declaration or a grade specified to your line? Contact our technical centre.