Plumbing made from acrylonitrile butadiene styrene (ABS) plastic pipe is joined together with cement adhesive and fittings. Plastic pipe’s ease of joining is one of it’s advantages over copper and iron piping. It does not require soldering, so there is no danger of starting a fire when installing or repairing it as there is with copper, and unlike no-hub iron pipe, it can be worked on in areas with limited access. Joints are highly leak-resistant once cemented, the inner bore is very smooth, which helps solid waste pass and lessens frictional loss.
On the downside, working around ABS pipe involves exposure to fumes from the cement adhesive. Taking a few safety precautions, such as wearing latex gloves and a breathing mask, and making sure the work space is well ventilated with fans, will go a long way to alleviating health risks.
Cements for ABS Pipe
One-part solvent type adhesive is used for joining acrylonitrile butadiene styrene pipe. A couple of well know brand names are Hercules and Oatey. It is available in varying viscosities for use with different diameter piping. There are also cements on the market for use in hot, dry climates which cure slower.
All-purpose formula cements are also made for ABS, PVC and other plastic pipe, but since they are not specifically designed for ABS, some local codes do not allow them. It is best to stick with ABS-specific cement.
Always wear latex gloves when working with abs cement. Be sure your work area is well ventilated.
Step by Step
Step 1: After cutting the ABS pipe, the outside and inside edge of the pipe should be deburred; you can use a pocketknife. The reason for this is to ensure that when the pipe is offered into the fitting, the gap between the two pieces fills up evenly with cement without pushing a bead out into the inside of the fitting.
Step 2: Make sure the pipe and fitting surfaces to be joined are clean and have no oil or grime on them. Apply ABS cement around the outside of the pipe and the inside of the fitting. Smaller size containers of cement have built-in applicators. For larger jobs where you are using the bigger containers, and for vertical joints, wooden handle bristle brushes are available for applying the cement from plumber’s suppliers. Put enough on to make the pipe slippery. The cement acts to reduce friction between the two parts, so if you don’t apply enough, you will have a hard time inserting the pipe. On the other hand, applying too much cement will make a mess and could build up inside around the pipe end, reducing the effective inner diameter size of the pipe. It takes a while to get a feel for how much is just the right amount.
Step 3: Push the fitting and pipe together, until the pieces bottom out on each other. The fittings are designed with a slight taper to them to allow room for the adhesive, so once the two parts are shoved together, it becomes pretty hard to pull them apart again. Additionally, the cement sets up pretty quickly. If you have not cut your pipe to the proper length, the whole assembly will have to be scrapped. The bigger the diameter pipe, the more force required to assemble.
Step 4: It is recommended to twist the pipe a quarter turn once assembled, in order to fully spread the cement inside the joint. If you are joining pipe to a change of direction elbow or angled branch fitting that needs to oriented properly, this part can throw you off. There is a trick for this, though. Before joining the pipe and fitting, make a mark with a grease pencil along the length of both parts near the join to match. Then when joining them, insert the pipe with the match mark one quarter turn away from where it should end up. That way, after you have the two parts seated, you make the quarter turn twist and can quickly get the right orientation as the marks line up, before the cement starts to set up and freeze the position.
Step 5: Clean away any excess cement on the outside of the joint, using a spare rag. ABS cement is solvent based, and creates a bond by actually melting the two parts together in a sort of chemical weld. Excess amounts can eat away through outer layers of foam core ABS pipe, leading to pipe breakage.