Product Details

No. 4 Epoxy Sealer Undercoat


No.4 Epoxy Sealer Undercoat is a professional grade primer ideally suited to lengthy new-build or repaint projects where different epoxy surfacers, undercoats and fairing compounds - of different ages - require to be sealed and prepared for final finishing.

In repaint situations where areas of the same job may be spot-filled, have existing sanded polyurethane finish and / or sanded epoxy undercoat, No.4 Epoxy Sealer Undercoat provides an excellent one-step tie-coat and sealer prior to applying urethane finish coats.

No.4 Epoxy Sealer Undercoat may be top-coated with acrylic or polyester urethane finishes and is especially formulated as a sealer under Elite Polyurethane, Elite Pro~Spray, and Boero Challenger HT finishes.

Download: No. 4 Epoxy Sealer Undercoat Data Sheet


No.4 Epoxy Sealer Undercoat is an excellent adhesion coat when applying a new finish over existing aged, and suitably prepared, polyester or acrylic urethane gloss coatings.

  • Available in a carefully selected grey tone allowing easy obliteration with low opacity finish coats.
  • Excellent lay-down qualities minimise the need for sanding prior to application of gloss finish coats.
  • In a multi-coat sequence No.4 Epoxy Sealer Undercoat can provide priming and barrier coat capabilities direct to prepared GRP and epoxy laminates.
  • Suitable for service above and below water

Specific Data:

Generic Type: Non-Inhibitive Epoxy Primer

Colour: White and Grey

Packaging: (NZ) 1.25 Litre (White Only) and 5 & 10 litre 
                   (Aust) 1.25 litre, 5 Litre, 10 Litre
                    Two component kits

Mix Ratio: 4 to 1 by volume

Gloss: Low Sheen

Flash Point: -4°C

Thinner: Spray Altex Thinner #12, Brush/Roller Altex Thinner #22

Pot Life: 16 hours at 20°C

Induction Time: 15 minutes

Storage: Store under cool, dry conditions

Density: 1.23 kg per mixed litre

Volume Solids (Mixed): 39%

Theoretical Coverage Rate: 7.8 sq metres per litre at 50 microns dry

Recommended Film Thickness Per Coat: 128 - 192 microns wet to obtain          50 - 75 microns dry

Application: Spray, brush or roller

Dry Times (50 µm DFT / 25°C / 50% RH):

Tack Free : 1 hr

Min. Recoat : 1 hr with itself, 12 hrs with other products

Max. Recoat: Undercover with Polyurethane:14 days without sanding. 3 months  with sanding within 7 days of finish coating

Outside with Polyurethane: 10 days without sanding. 3 weeks with sanding within 7 days of finish coating.

Self Recoat: 14 days without light sanding.