Sem High-Build Primer Surfacer Gray 16 oz. (6/pack)

Sem High-Build Primer Surfacer Gray 16 oz. (6/pack)

The SEM High-Build Primer Surfacer Gray delivers a strong, smooth base layer for automotive and metal refinishing projects. This primer works on steel, aluminum, fiberglass, plastic, SMC, and other substrates. 

First, this primer offers excellent adhesion and high film build. As a result, it fills minor scratches, imperfections, or irregularities on metal or plastic surfaces. This creates a uniform foundation before applying topcoat or color coat. 

Next, application is straightforward. Spray 2–3 medium wet coats. Allow 5–10 minutes flash time between coats. Then let it dry — usually within an hour.  After drying, you can wet-sand or dry-sand with 320–400 grit sandpaper to achieve a smooth surface ready for paint. 

Also, this primer adapts to both rigid and flexible substrates. Therefore, you can use it on body panels, plastic bumpers, fiberglass parts, or aluminum elements without compromising adhesion or finish quality. 

Furthermore, the surfacer is easy to sand, which helps you fine-tune the surface level before final painting. Because sanding is smoother, you save time and reduce the risk of sanding marks. 

For best results, always clean the surface thoroughly before application. For metal and aluminum, degrease and remove rust or old coating first. For plastic or fiberglass, start with a proper plastic pre-prep cleaning. Then apply primer and sand afterward. This ensures maximum adhesion and a flawless paint job. 

Overall, SEM High-Build Primer Surfacer Gray gives you a durable, smooth, and professional-grade base. Whether you restore a classic car, repair a panel, or refinish custom bodywork — this primer makes sure your topcoat adheres well and looks great. Its ability to fill imperfections, sand easily, and work on diverse materials makes it a go-to for both DIY enthusiasts and professional body shops.