Primerless MMA Structural Adhesives. The Crestabond range of M7 / PP (1:1) and M1 (10:1) structural adhesives are unique to the market due to the incorporation of our novel tougheners. Crestabond adhesives benefit from a range of working times to suit different applications and can be used with a manual or pneumatic gun. We have brochure downloads containing Adhesive Selection Guides here.