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Solvent Welding Best Practices: Choosing the Right Daubers

Solvent welding is an effective, time-tested installation method for CPVC piping systems, using chemistry to form a reliable, long-lasting bond. But like any building material, it’s important to follow instructions and best practices to ensure your CPVC pipes are fitted properly and will perform as designed. This includes something as simple as the application dauber you choose.

In the two-step solvent-weld process, daubers are used to apply the primer and solvent cement to the outside of the pipe before assembling the joint. Using the wrong size dauber can result in too little or too much primer or solvent cement, which can impact the integrity of the joint.

Often, installers simply choose the cheapest daubers or the dauber that comes inside the solvent weld can. Instead, select the dauber whose size is best suited to the pipe being installed: The dauber should be at least half the diameter of the pipe; if you’re installing a 2” pipe, for example, you’ll need at least a 1” dauber.

Keep in mind that many solvent weld canisters come with a dauber of just 3/8” to ½”, so you’ll often need to purchase daubers separately for pipes of 1” and larger; daubers are available up to 1 1/2”, for use with 3” pipe. For pipes of larger diameter, use a swab, which comes one size fits all.

To apply the primer, use the dauber to apply a heavy, even coat inside the fitting socket, keeping the surface and applicator wet until the surface has been softened. Then, drain any puddles of primer from the fitting socket. Next, apply the primer onto the end of the pipe 1/2″ beyond the depth of the fitting socket. Then for a second time, work a second coat of primer into the fitting socket.

Next, apply a heavy, even layer of solvent cement on the pipe end, then apply a medium layer of solvent cement into the fitting socket. Apply a second, heavy layer of solvent cement to the pipe end.

Ensure proper coverage of cement on the pipe and fitting. Too little solvent cement can result in gaps and leak paths, and too much solvent cement may puddle in the fittings and/or pipe, softening the material.

To learn the rest of the step-by-step process for solvent welding, check out our blog post and video here.

Feature image: Courtesy Oatey