How to Install Pipe

Working with copper, steel and PEX

Article and photos by Steve Maxwell

Plumbing, pipes and fittings are evolving in major ways, and by understanding these changes you can make wiser construction decisions. Along with technical innovations you’ll also find tried and true methods for successfully dealing with plumbing challenges. Combining new materials and old techniques is often the way success happens in the real world, and what you’ll find here are some of the things I’ve learned after my first 25 years of installing pipe.

Innovation is breaking out in all aspects of the building industry, and a handful of specific plumbing technologies are rapidly improving the way pipes of all kinds are installed. Another change is the way more plumbing features are being installed in new homes and major renovations. More lavish kitchens, greater numbers of bathrooms in each home, plus the growing popularity of hydronic heating systems mean that a whole lot more pipes and fittings are being used in today’s best building projects.

For many years copper pipes and fittings were the industry standard for water supply pipes because they’re reliable, simple and available everywhere. And while copper is still a great system, it’s expensive and limited. The rigid nature of the pipe, and the need to solder copper pipe fittings has opened the door to alternatives that are now stealing the show. And of all these newer options, PEX pipe is leading the way.

Fastest Way to Do PEX

The word PEX stands for cross-linked polyethylene, and although it took a while for this pipe to make it to North America from Europe, the PEX revolution is now in full swing here in Canada. I’ve used various PEX pipe and connection systems over the last 10 years, and my current favourite is Uponor ProPEX. It’s the quickest system to install, it’s flexible, tough and can be used for water supply systems and hydronic heating. ProPEX is aimed at plumbing professionals, and it’s got unique features that help boost installation efficiency and reliability.

Expand, insert, hold, release. These are the four steps involved in making any ProPEX connection, and the whole process takes less than 30 seconds per joint. PEX pipe is made in a couple of versions, and the elastic nature of PEXa pipe makes the ProPEX system possible.

PEXa is a type of pipe that’s made by a handful of manufacturers, and it looks like ordinary plastic pipe at first glance. What you can’t see is something called a molecular memory, and it lets PEXa do two important things. First, this kind of pipe always seeks to return to its former shape, and this is why the expansion and contraction process makes ProPEX connections possible. Think of PEXa as a slow-moving elastic. After placing a PEX joint ring over the end of the pipe, swell the end with an expander tool. PEXa holds this swollen shape long enough to slide over the fitting before shrinking down over it. The result is a pipe that’s constantly gripping the fitting of its own accord tightly, without relying on rigid metal bands that have been compressed with a tool. Leaks are virtually unheard of.

The ability to repair kinks is another advantage of PEXa pipe. As with any plastic pipe that’s bent too sharply, PEXa will kink and hold this shape to a certain extent after straightening out. Kinks are bad because they restrict water flow, but they can be completely removed with heat. Use a heat gun to evenly warm the kinked area until the opaque white pipe turns clear. The kink will disappear, and remain gone after letting the pipe cool and become opaque again.

Besides speed of installation, reliability and ease of repair, the PEX expansion system also means that the internal diameter of fittings is the same as the pipe itself. You get better flow rate and less restriction compared with crimp-style PEX connections that can only slide over fittings significantly smaller than the pipe itself. Also, since it’s physically impossible to assemble a ProPEX connection that’s not tight, it eliminates the leak risk posed by assembled but accidentally uncrimped PEX connections in systems that use metal crimp rings.

Cutting, Threading and Sealing Steel Pipes

Steel pipe might seem old fashioned, but 1-inch and 1¼-inch diameters are often useful for making pipe connections to and from boilers and outdoor wood furnaces. I use them all the time. You might also need to deal with steel pipe if you’re renovating an iron radiator heating system or installing iron rads from scratch. And while cutting and threading steel pipe might seem like a difficult task, it’s actually surprisingly easy. Pipe can be cut to length with a hand hacksaw, a cordless hacksaw or a chopsaw spinning a metal-cutting carbide blade. The simplest way to cut threads on pipe like this is with a hand-operated die. Although the pipe is large, it’s still practical to cut threads by hand. Rather than having to run out to a plumbing shop to have pipe threaded after cutting to length, just rent a simple pipe threading die and handle so you can custom thread on site holding the pipe in the worksite pipe vice you use to assemble the fittings. The same process works well for shortening brass nipples as well.

One more thing. Steel pipes come in two types: plain steel and galvanized. Although you’d think galvanized would make sense for hydronic heating systems, plain steel is better. It’s not unusual for the zinc coating on galvanized pipes to react with hot water to create a kind of sludge that plugs hydronic systems in time. Never use galvanized in heating applications. And while plain steel pipes might seem prone to rust, they’re not. The heating of water in a hydronic system drives all the oxygen out of the water, so rust doesn’toccur, even after many decades of continuous service.

Threaded fittings can be a big part of any hydronic heating system, but pipe threads never seal on their own. That’s why threaded pipe connections are always wrapped in Teflon tape or coated with some thread-sealing compound before assembly. Trouble is, this is precisely where you can run into some very disappointing trouble with the kind of larger diameter pipes used in heating systems.

The fact is that neither Teflon tape nor standard pipe-sealing compounds are 100 per cent reliable when it comes to making threaded connections on pipes bigger than ¾-inch in diameter. And the worst part is, you never find out which seemingly good connections are actually leaky until your system is completely assembled, filled with water and operating under pressure.

You can save yourself a lot of worry and hassle by using automotive thread-sealing liquid rated for hydraulic and pneumatic installations, instead of Teflon tape or ordinary pipe goop. After making many dozens of threaded pipe connections using this stuff over the years, I’ve never had a single leak, which is much more than I can say about other sealing options. None of the sealants I’ve used are rated for potable water systems, and sealants like these are expensive. Despite these drawbacks, I never use anything else.

Copper Solder Step-By-Step

Copper pipe may be losing market share, but you should still know how to join fittings and pipes with solder. The process uses heat and molten metal to join fittings permanently, and it’s one of those jobs that’s much easier than its reputation. Follow these three steps for leak-proof results:

Clean all joint surfaces so they’re bright. I use a copper pipe fitting brush to clean the inside of copper fittings, and sand paper to clean the outside of pipes that slip into the fittings. Sand the length of solder you’ll be using, too.

Apply flux paste to both joint surfaces with a brush. Flux is mildly acidic and it further cleans the metal so the molten solder can enter the pours of the copper when hot.

Assemble the joint, then heat it with a propane torch. The trick is to apply enough heat so the heat of the copper pipe itself melts the solder at the next stage, rather than the heat of the propane flame. Too much heat causes the flux to burn, leaving a brown residue that prevents solder from sticking to the copper.

Use one hand to keep the torch flame moving on the joint area, and your other hand to hold the roll of solder so the end is touching the edge of the fitting. If the copper is the right temperature, solder will quickly melt and flow into and all the way around the joint. Capillary action will draw liquid solder up into a joint that’s higher than the edge of the fitting, but you’ll find it easier to solder neatly if you complete as many connections as possible with joints pointing downwards.

Methods and materials for successfully installing pipes for domestic water supply and hydronic heating systems are evolving fast. The trick is to keep your eyes open for worthwhile new stuff coming out, while also retaining the old techniques that still make sense.