SEM Sand Free adhesion promoter for plastics 11.6 oz — wet-on-wet primer activator, reduces sanding

SEM 38363 Sand Free is a wet-on-wet adhesion promoter formulated to soften specific plastic substrates so coatings bond without aggressive sanding.

When working with plastic bumpers, trim pieces, and other automotive plastics that resist standard sanding and priming, getting a durable topcoat starts with a primer that actually sticks. SEM's Sand Free is designed to condition and soften certain hard-to-prepare plastics so subsequent primers and paints adhere more reliably. It’s supplied in an 11.6 oz container sized for workshop use and spot repairs.

How does Sand Free help when plastics won’t sand properly?

Sand Free contains chemistry that lightly softens targeted plastic surfaces, creating a surface more receptive to wet-on-wet primers without heavy abrasion. This avoids the need for aggressive sanding that can damage thin or intricate parts. It’s intended for use where mechanical sanding is impractical or risks altering the part geometry.

• Softens surface polymers to improve mechanical grip of primers
• Enables wet-on-wet application for faster workflow
• Reduces reliance on heavy sanding or plastic-specific primers

Which plastic parts are suitable for SEM Sand Free?

Sand Free is meant for certain hard-to-sand plastics commonly found in automotive exterior trim and bumpers. It’s important to test on a small area first because not all plastic formulations react the same way. Use it where compatibility is confirmed and avoid materials explicitly excluded by SEM technical data.

• Ideal for many bumper and trim polymers that resist sanding
• Appropriate for spot repairs and partial panel refinishing
• Not a universal solution — perform compatibility checks first

How do I apply Sand Free for best results?

Apply Sand Free as part of a wet-on-wet process following SEM application instructions and safety guidelines. After treating the substrate, allow the product to act briefly according to product directions, then apply the recommended primer or sealer while the surface remains receptive. Avoid over-application and ensure proper ventilation and protective equipment.

• Follow SEM’s timing and recoat window for wet-on-wet systems
• Use appropriate PPE and work in a ventilated area
• Test and confirm adhesion before proceeding to full refinishing

Who is this for? SEM 38363 Sand Free is aimed at automotive refinish professionals, collision repair shops, and experienced DIYers who encounter plastic parts that are difficult to abrade and prime. If you need a targeted adhesion promoter to simplify refinishing of plastics and reduce sanding time while maintaining reliable paint adhesion, Sand Free offers a practical option when used according to product guidelines.