PVC Glue Pipe Joints

PVC Solvent Cement for Pipe Joints

PVC solvent cement (commonly sold in Brazil under brands such as Tigre and Krona) doesn't glue parts together so much as weld them. It partly dissolves the plastic on both surfaces, and when that re−solidifies the two pieces are effectively one. How much you go through comes down mostly to pipe diameter. A handy approximation is grams ≈ 0.15 × ømm, which works out to somewhere around 5–15 g per joint for pipes between ø 20 mm and ø 100 mm.

Here's how it should go. Wipe both surfaces with PVC cleaner (primer) first. Spread a thin, even layer of cement on the outside of the pipe and the inside of the fitting, then push them together with a slight twist and hold for roughly 30 seconds. After about 5 minutes it has set enough to handle gently, but give it a full 24 hours before you pressurize the line. The relevant Brazilian standards are NBR 5648 (cold water) and NBR 14486 (sewage).

Applications

Think cold water supply lines, sewage and rainwater drainage, low−pressure irrigation, electrical conduit, and the kind of plumbing repairs people do themselves. Where it falls short is hot water, compressed air, and anything running at high pressure. Those jobs call for thermal fusion (CPVC, PPR) or threaded and flanged connections instead.

FAQ

Can I skip the primer? Better not. The cleaner strips off oils and softens the surface at a microscopic level, and that softening is what lets the cement actually weld the parts. Skip it and you'll often find leaks once the line is under pressure.

How long before I can fill the pipe with water? Give low−pressure lines at least an hour, and pressurized supply lines a full 24 hours. Cold, humid weather drags the curing out longer.

Does the cement expire? It does, usually 2 years sealed. If what's in the can has gone thick, lumpy, or stringy, throw it out. It won't bond reliably anymore.