This is a common failure point called Solvent Attack. Many contact adhesives and polyester resins contain Styrene Monomer which instantly dissolves EPS and attacks low-grade PU.
- The Solution for EPS/XPS: Use Epoxy Resin (low-VOC) or Polyurethane Adhesive (Gorilla Glue type chemistry).
- The Solution for PVC/PET: Use Methyl Methacrylate (MMA) structural adhesives for rapid production (like bonding truck panels) or Epoxy for high-strength marine work.
