SEM Grey 16 oz High-Build Acrylic Primer Aerosol — Flexible, Fast-Filling Adhesion for Metal, Aluminum & Plastics

SEM's 42013 Grey High Build Acrylic Primer in a 16 oz. aerosol gives professional-level surface buildup and adhesion in a compact spray. It’s designed to create a smooth, uniform foundation prior to painting automotive panels, parts and trim made of various materials. The primer’s elastomeric acrylic chemistry provides body for minor surface correction while maintaining enough flexibility for components that expand and contract.

What surfaces can this primer reliably bond to?

This primer adheres to common automotive substrates including bare and painted metals, aluminum, many plastics and urethane parts when properly prepared. It’s formulated to promote mechanical and chemical grip across mixed-material jobs typical in collision repair and refinishing.

• Steel and bare metal: cleans, etches slightly and bonds for topcoat adhesion
• Aluminum: formulated for good adhesion after proper cleaning/deoxidizing
• Urethane and many plastics: use adhesion promoter when required
• Previously painted panels: scuff, clean, and apply for uniform primer coat

How does it help achieve a smooth, paint-ready surface?

The high-build formula lays down a thicker film than standard primers to fill light scratches, pinholes and minor surface imperfections. That reduces the amount of wet or dry sanding needed and produces a consistent base for color coats and clear coats.

• High-build film levels shallow imperfections fast
• Sands readily to create even feather edges and smooth transitions
• Reduces multiple filler applications on small defects
• Compatible with most basecoat/clearcoat systems when topcoated per instructions

How should I apply and finish the SEM 42013 primer?

Shake the aerosol thoroughly, apply in light, even passes, and allow proper flash time between coats to avoid runs. Build film in several thin layers to reach desired thickness, then sand with recommended grits before applying topcoat.

• Shake can vigorously for at least one minute after mixing ball moves freely
• Apply 2–4 light coats, holding the can the manufacturer’s recommended distance
• Let flash between coats and cure per label before sanding or topcoating
• Sanding: start with medium grit, finish with fine grit for a smooth base

Are there any performance or handling considerations to keep in mind?

The aerosol format offers convenience for touch-ups and small panels, but follow temperature and ventilation guidance for optimal film formation. Use appropriate personal protective equipment and observe surface prep steps to maximize adhesion and finish quality.

• Use in well-ventilated areas; wear a respirator when spraying
• Control temperature and humidity per product recommendations
• Test adhesion on unfamiliar plastics; use adhesion promoter if needed
• Store and dispose of cans according to local regulations

Who is this for? SEM 42013 is intended for automotive refinishers, body-shop technicians and experienced DIYers who need a high-build, flexible primer in an easy-to-use aerosol. It’s ideal for spot repairs, trim pieces and small panels where a durable, sandable primer is required before applying color and clearcoat systems. For larger jobs, consider bulk high-build surfacers, but for precision touch-ups and mixed-material parts, this 16 oz. can offers a professional foundation with minimal setup.