Monthly Archives: November 2012

  • A Guide to Solvent Cementing PVC

    Man uses PVC Solvent Cement

    How to "Glue" PVC

    Surely you've heard the expression, “a chain is only as strong as its weakest link.” Polyvinyl Chloride is an impressively strong and rigid material that’s great for handling liquid media, but any PVC infrastructure you create is only as strong as its weakest link. In the case of piping, that means your joints.

    Properly cemented PVC joints are incredibly strong, and will stay watertight for years. The cementing process is not overly complicated or difficult, but it does require some thought and attention to detail. Below we’ll explain step-by-step how to properly prep and join PVC pipe and fittings.

    Preparing the Pipe:

    For a strong joint, it’s important to have a clean, straight cut on your pipe. We recommend using a PVC cutter tool made especially for pipe, or a saw that will not leave a rough, gummed up edge on the pipe. Once your cut is made, use a file to remove all burs and create a smooth edge.

    Some users will tell you that a smooth edge is good enough, but we recommend using a file or bevel tool to create a small bevel on the outside edge of the pipe lip. This bevel is called a chamfer. A chamfer will help create a good fit and watertight seal inside your fitting. The next step of the prep stage is to remove all dirt, grease, and moisture from the surfaces that will be joined. Any contaminants will compromise the strength of the bond.

    Before applying any primer or glue you will want to dry fit your joint. This just means fitting the parts together without glue. The pipe should go into the fitting easily at first and then become tighter as it is completely inserted. The joint shouldn't be so tight that you can’t fit the pipe into the socket completely.

    If your job requires an exact angle or configuration, mark your joint during the dry fit to ensure parts are lined up properly during the cementing. Creating a straight line across the joint with a marker or pencil will allow you to replicate the dry fit position later.

    Priming your joint:

    Gather all the materials you will need to complete the joint. Once you begin priming, it is important to work quickly so that the primer and glue don’t have a chance to dry up. The wet chemical reaction is what softens the PVC and allows it to form a strong bond.

    Use a primer applicator (equal to about half the pipe diameter in size) to generously apply your PVC primer to the inside of the fitting socket. Be sure the socket is completely coated, but that there are no puddles in the socket.

    Next, apply the primer to the outside of the pipe end. Again, apply generously without leaving any dry areas. The primer should be applied a half inch beyond the depth of the socket. When this is done, apply another layer of primer to the inside of the fitting socket and move quickly to begin applying cement.

    Cementing:

    Make sure your cement is stirred well, and within its recommended use date. Use a proper cement applicator swab and begin working an even layer of cement onto the pipe. Don’t glop the cement on, but make sure it is thick enough that it won’t dry within the next few minutes. Do the same for the inside socket, and then give the pipe end one more layer. Do not wait for these to dry – immediately assemble the pipe and fitting.

    Use a good amount of force and give the pipe a ¼ turn to distribute the cement and help the pipe reach the end of the socket. Hold the joint in place for at least 30 seconds while the cement sets. You should see a solid bead of cement around the complete circumference of the joint.

    Use a rag to remove excess cement, being careful to not move or disturb the joint. To reach full strength the joint must cure for the recommended amount of time. See the chart below for approximate curing guidelines.

    Average Time Schedule of PVC/CPVC Solvent Cement Cure

    Temperature Range (during assembly and cure period) Pipe sizes½” to 1 ¼” Pipe sizes1 ½” to 2” Pipe sizes2 ½” to 8” Pipe sizes10” to 15” Pipe sizes15” +
    60 – 100 degrees F 15 min (up to 160psi)6 hrs (160-370psi) 30 min (up to 160psi)12 hrs (160-315psi) 1 ½ hrs (up to 160 psi)24 hrs (160-315psi) 48 hrs (up to 100psi) 72 hrs (up to 100psi)
    40 – 60 degrees F 20 min (up to 160psi)12 hrs (160-370psi) 45 min (up to 160psi)24 hrs (160-315psi) 4 hrs (up to 160 psi)48 hrs (160-315psi) 96 hrs (up to 100psi) 6 days (up to 100psi)
    0 – 40 degrees F 30 min (up to 160psi)48 hrs (160-370psi) 1 hr (up to 160psi)96 hrs (160-315psi) 72 hrs (up to 160 psi)8 days (160-315psi) 8 days (up to 100psi) 14 days (up to 100psi)

    *In humidity levels over 60% allow for at least 50% longer cure time. Chart is a general reference only. All times are approximate and may vary based on conditions.

     

     

  • How do I cut PVC?

    PVC is a pretty awesome material. It’s strong, durable, and cheap. Those qualities have made it a popular material choice for all sorts of building and recreational applications worldwide. One common problem many PVC users face when they get their newly bought pipe home is “how do I cut this stuff?!” Cutting PVC isn’t very difficult, but using the right tools and techniques can make the difference between ill-fitting and leak-free.

    What to use:

    PVC Cutter - If you are cutting a smaller diameter pipe, a PVC pipe cutter tool works great. You can find these online and at most hardware stores. They look like a pair of hedge clippers that have been souped up a bit.

     Hacksaw - If you can’t find PVC cutters or you have a larger diameter pipe to cut, a hacksaw will work.

    Miter Saw - For less manual work, or for those of us who already have one of these babies in the garage, a miter saw can make quick work of cutting PVC.

    How to make the cut:

    Step one to any cut is measuring. The old adage “measure twice, cut once” comes in handy when you are working with limited pipe. Use a pencil or marker to indicate where you will make each cut. It’s a good idea to measure and cut your longest lengths first. That way you end up the most usable left over pipe if you botch a cut. If you’re using PVC cutters, follow the direction on packaging. Usually these tools will have a ratchet function that allows you to tighten the grip and apply steady pressure to the cut. These tools are extremely sharp, so use caution when handling. Fingers tend to be softer than PVC.

    If you are using a saw, patience is your friend. Especially with a miter saw – you will be tempted to try to speed through a cut like it’s wood. The problem here is that PVC is plastic. That means it melts. The heat created by the friction of the saw can really gum up your cut and give you a rugged edge. Take your time and focus on creating smooth cuts. It will save you time filing in the end anyway! If you’re using a hacksaw, clamp the pipe in with a vice if possible to stabilize and make for a square cut. Once you get most of the way through, turn the pipe to complete the cut.

    Refining the edge:

    Once you’ve cut your pipe take a look at the edge. It’s probably a little jagged or burred. Use a metal file or some strong sandpaper to smooth and even out the ends. You want to end up with a square end – meaning if you laid a flat plane over the cut end it would create a 90 degree angle with the pipe all the way around. File down and dust away any stray pieces of plastic, and you're ready to go.

    Note: If you are using the PVC for plumbing or any application that requires water-tight joints, we recommend you chamfer your pipe ends. This can be done by making a slight bevel all the way around the diameter of the pipe using a bevel tool or a file. This little lip will help form a water-tight seal where the pipe meets a fitting.

  • Do I Need to Use PVC Primer?

    Some will tell you that primer is not necessary to create strong PVC joints. Others swear by it and slather it on like their lives depend on it. While you may be able to create strong joints without it, primer is an important part in making sure your joints are as strong as they possibly can be.

    We recommend you use primer on any joints that will have liquid media passing through them.

    The purpose of primer is to begin the chemical reaction that softens PVC and to provide an even prepped surface for the solvent cement. As you may know, PVC joints are not glued together exactly, but fused through a chemical change. The softer the outer layer of your PVC, the better it will cement in your joint. This is how primer helps your joint strength.

    In many states plumbing inspectors will look for primer and only pass you if they see liberal use on all joints. Most primers are a vibrant purple color so that its use is evident, but there are also clear primers. If you're working on an inspected job, find out if that state requires the use of primer. If it does, choose a brand that offers a colored primer that will be easy to see, and use it liberally beyond where the pipe will meet the socket. If the inspector can't see it, there's no point in using it.

    When it comes time to apply your primer make sure you are 100% ready to prime AND cement. Primer is effective only when wet, so you need to move quickly once you begin. Usually PVC jobs require about half the amount of primer as they do cement.

    In short, primer is your friend. It may not be completely necessary on all jobs, but we recommend you take all the precautions available to ensure your joints are leak-free and as strong as possible.

    CIS supports Weld-On Primers & Adhesives for Plastics

  • How Much Glue Do I Need? – PVC/CPVC Solvent Cement Guide

    Gluing-PVCLooking to take on a PVC/CPVC project? PVC “glue” isn't really glue at all, but solvent cement. The cement creates a chemical reaction that actually softens the rigid PVC material and allows it to fuse to another piece of softened PVC. Before purchasing your cement, do a little research. You need a product that is specially formulated for PVC. Don’t try to use that old epoxy you have in the garage. A few well-known cement companies are IPS (WELD-ON) and Oatey.

    Generally speaking, a little PVC solvent cement goes a long way. If you are simply replacing the sink trap in your bathroom for instance, one quart of cement will be way more than enough. If your project is a little bigger though, you may be wondering how much cement you will need to complete the job. We’ve created a chart to help you calculate the approximate amount you should budget for.

    Before you begin, you’ll need to know the size pipe you are using and about how many joints you plan on creating. Use the chart below to find your pipe size – then look over to see how many joints can be cemented using one quart. Keep in mind these numbers are approximate, and should only be used as a rough estimate.

    Average Number of Joints per Quart of PVC/CPVC Solvent Cement

    Pipe Diameter ½” ¾” 1” 1 ½” 2” 3” 4” 6” 8” 10” 12” 15”
    # of Joints 300 200 125 90 60 40 30 10 5 2-3 1-2 3/4

    *One joint means one socket. Chart is a general reference only. All numbers are approximate and will vary based on conditions.

    Will your job require large diameter pipe? If so, you’ll probably want to look into bulk ordering your cement. Cement suppliers offer quart sized containers for small to medium sized jobs, but they often have gallon sizes available and will give you a price break for ordering in bulk.

    Wondering how much primer you will need? Typically a job will require about half as much primer as it does cement. If your job takes 4 quarts of cement, for instance, you will need about 2 quarts of primer. Be sure you check the use date on your products before beginning a job. Typical shelf life is about 2-3 years for most PVC cements. If your old can of cement has been sitting in the garage for longer than that – throw it out! No sense in compromising a job over a quart of cement.

     

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