solventwelding

Solvent welding is a method of joining thermoplastic materials by using a solvent-based cement that softens the surface to allow fusion of the parts. When applied, the solvent dissolves a thin layer of the polymer; upon evaporation the softened surfaces flow together and form a continuous, monolithic joint as the material re-hardens. This process is often referred to as solvent bonding or solvent cement welding.

The method is widely used with common thermoplastics such as polyvinyl chloride (PVC), chlorinated PVC (CPVC), acrylonitrile butadiene styrene (ABS), and some acrylics. The exact solvent system varies by material: PVC/CPVC typically use cement blends based on ketones and chlorinated solvents; ABS uses acetone- or MEK-based solvents; acrylics may require specialized solvents. Surface preparation is important, and primers or cleaners are sometimes recommended to improve adhesion and solvent wetting.

Procedure typically involves cleaning and dry-fitting the parts, applying an appropriate solvent cement to one or both mating surfaces, inserting the parts together with a twist to distribute the cement, and maintaining position until the solvent has partially evaporated and the joint sets. Cure times depend on material, solvent, joint geometry, and environmental conditions; many joints achieve handling strength within minutes but require hours to reach full strength.

Advantages include strong, leak-proof joints and relatively fast assembly for piping and fabrication. Limitations include the need for compatible materials, proper ventilation due to fumes, and the fact that the joint strength depends on solvent action rather than mechanical fasteners. Solvent welding is common in plumbing, irrigation, aquariums, and certain fabrication applications.