What process fuses plastic pipe and fittings together chemically?

What process fuses plastic pipe and fittings together chemically?

• A. Solvent Weld
• B. Solder
• C. Brazing
• D. Compression

Answer: (A)

Solvent welding is how plastic pipe joints are chemically fused. The solvent cement contains chemicals that soften the outer surfaces of the pipe and fitting. When you push them together, these softened surfaces mingle and flow, and as the solvent evaporates, the plastics fuse at a molecular level to form one continuous, leak-tight joint. This approach is specifically used for thermoplastics like PVC and CPVC, where the goal is a true chemical bond rather than a mechanical hold. Solder and brazing, by contrast, join materials by melting a filler metal at high heat, which is typical for metals (and sometimes for plastic-metal combos), not by chemically fusing the plastic itself. Compression joints rely on clamping and a gasket to seal, without any chemical bonding of the plastic.

Solvent welding is how plastic pipe joints are chemically fused. The solvent cement contains chemicals that soften the outer surfaces of the pipe and fitting. When you push them together, these softened surfaces mingle and flow, and as the solvent evaporates, the plastics fuse at a molecular level to form one continuous, leak-tight joint. This approach is specifically used for thermoplastics like PVC and CPVC, where the goal is a true chemical bond rather than a mechanical hold.

Solder and brazing, by contrast, join materials by melting a filler metal at high heat, which is typical for metals (and sometimes for plastic-metal combos), not by chemically fusing the plastic itself. Compression joints rely on clamping and a gasket to seal, without any chemical bonding of the plastic.