PPG SigmaFast 278, formerly known as Amercoat 278, is a two-component, high solids, zinc phosphate epoxy primer and buildcoat for use in protective coating systems with excellent corrosion resistance in atmospheric exposure. Curing at temperatures down to -5°C (23°F), SigmaFast 278 can be overcoated with various two-pack epoxy and polyurethane coatings after 2 hours.

Features & Benefits

• Available in 2,300+ colours, inc. RAL, BS, NCS & the new NCS 2050 colours
• Epoxy primer or buildcoat in protective coating systems
• Excellent corrosion resistance in atmospheric exposure
• For use on steel; galvanised or primed
• Cures at temperatures down to -5°C (23°F)
• Speed curing in steel fabrication
• Easy application by airless spray
• Wide application range
• Can be used at temperatures down to -5°C (23°F)
• Ensure substrates is dry and clear of ice
• Touch dry after 2 hours
• Can be overcoated after 2 hours
• Overcoats with various two-pack epoxy and polyurethane coatings
• 1 hour pot life
• Used at Metaalbescherming Katwijk (MBK), Rozenburg, Holland, large-scale operator in steel bar preservation with a production capacity of approximately 12,000 m² per week.
• Also used by Metalúrgica del Deza (Metaldeza), a Spanish company that  specializes in the design, manufacture and assembly of metal structures and metalwork, including infrastructure projects, pipelines, filters, and vessels under pressure. The company holds ISO 9001 and OSHAS 18001, ISO 14001, EMA’S and is certificated by ASME.
• See below for more information on surface preparation, application details and curing times

Note:

Epoxies will yellow over time and this will be more visible in white and off-white. SigmaFast 278 should be used for noncosmetic areas only.

Product Data

Two-component, high solids, zinc phosphate epoxy primer and buildcoat

Notes:

• Refer below for more details on spreading rate and film thickness, overcoating intervals and curing times

Surface Preparation

Recommended Substrate Conditions and Temperatures

Substrate conditions

Steel

• Blast cleaned to ISO-Sa2½ or minimum SSPC SP-6, blasting profile 40 – 70 µm (1.6 – 2.8 mils) or power tool cleaned to minimum ISO-St3 / SSPC SP3

Galvanized steel

• Surface must be dry and free from any contamination
• Surface should be sufficiently roughened (e.g. sandpapering, sweep blasting)

Primed steel or previous coat

• Previous suitable coat must be dry and free from any contamination
• Surface of previous coat should be sufficiently roughened if necessary
• When applied to zinc silicate, a mist coat and full coat technique is required

Substrate Temperature & Application Conditions

• Substrate temperature during application and curing should be at least 3°C (5°F) above dew point
• Substrate temperature during application and curing down to -5°C (23°F) is acceptable; provided the substrate is free from ice and dry

Application

Instructions for Use

Mixing ratio by volume: base to hardener 75:25 (3:1)

• The temperature of the paint should preferably be above 15°C (59°F), otherwise extra thinner may be required to obtain application viscosity
• Adding too much thinner results in reduced sag resistance and slower cure
• Thinner should be added after mixing the components

Induction Time

None.

Air Spray

Recommended thinner

• THINNER 91-92

Volume of thinner

• 0 - 10%, depending on required thickness and application conditions

Nozzle orifice

• 1.7 – 2.0 mm (approx. 0.070 – 0.079 in)

Nozzle pressure

• 0.3 - 0.4 MPa (approx. 3 - 4 bar; 44 - 58 p.s.i.)

Airless Spray

Recommended thinner

• THINNER 91-92

Volume of thinner

• 0 - 10%, 30 - 40% when mist coat applied

Nozzle orifice

• Approx. 0.46 – 0.53 mm (0.018 – 0.021 in)

Nozzle pressure

• 20.0 - 25.0 MPa (approx. 200 - 250 bar; 2901 - 3626 p.s.i.)

Brush/roller

Recommended thinner

• THINNER 91-92

Volume of thinner

• 0 – 5%

Notes:

• Application by roller will leave roller marking and is suitable for minimum DFT requirements only
• A roller suitable for epoxy application must be used
• Application by brush may show brush marking, due to the thixatropic nature of the paint and is most suitable to small areas, tight angle areas or for stripe coating or touch-up

Cleaning Solvent

• 90-53

Spreading Rate and Film Thickness

Overcoating interval for DFT up to 125 µm (5.0 mils)

Notes:

• This product has an unlimited maximum overcoating interval provided the surface is free from chalking and other contamination, in which case it should be cleaned and roughened up to ensure good adhesion of subsequent coat
• The optimum intercoat adhesion is obtained when the subsequent coating is applied before the full cure time of the previous coating has elapsed
• This product will yellow quickly when exposed to sunlight; this has no influence on the anti-corrosive performance and will not affect the topcoat

Curing time for DFT up to 125 µm (5.0 mils)

Notes:

• Adequate ventilation must be maintained during application and curing (please refer to information sheets information sheet 1433 and Directives for Ventilation Practice (information sheet 1434)

Pot Life (at application viscosity)

Note:

• Due to exothermic reaction, temperature during and after mixing may increase

Safety Precautions

• For paint and recommended thinners, see information sheets information sheet 1430, information sheet 1431 and the relevant Material Safety Data Sheets in the attachments section above
• This is a solvent-borne paint and care should be taken to avoid inhalation of spray mist or vapor, as well as contact between the wet paint and exposed skin or eyes

References

• Conversion Tables (information sheet 1410)
• Explanation to product data sheets (information sheet 1411)
• Safety Indicators (information sheet 1430)
• Relative humidity - Substrate Temperature - Air Temperature (information sheet 1650)