Working with Pipe: Copper Tubing

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The cost of copper tubing varies in its relation to the cost of iron pipe. Even when it costs more, however, the finished cost is usually less because it's so easy to work with, the labor cost or time for installing copper is much less than for installing iron pipe. Copper is lighter and there fore easier to carry and put in place than iron. For the same inside diameter, it's quite a bit smaller on the out side, allowing smaller holes in studs and floors and less clearance for joints and fittings, Because flexible tubing can be bent around corners, it takes fewer fittings than iron pipe and the fittings it does need are quicker and easier to install. The tools needed to install a copper plumbing system cost far less than those needed for a similar iron pipe system, Copper is also more resistant to corrosion than iron pipe in most cases, so you have much less trouble with it rusting out. Don’t forget, however, that if you are thinking of installing a copper addition to an iron pipe system, you must consider galvanic action.

Pipe and Fittings

Two kinds of copper tubing are available. Soft tubing, which is easily bent, comes in straight lengths of 20 feet and coils of up to 100 feet, Hard tubing is rigid and must turn corners using elbow fittings just like iron pipe. It comes in 10- and 20-foot straight lengths.

Ill. 32 Copper Fittings: Solder fillings; 90-degree ell


Copper tubing comes in the same sizes as iron pipe— from ¼ to 2 1/2 inches. The actual outside diameter (OD.) of the tubing is ¼ inch larger than the nominal size, and the inside diameter (ID.) varies with the thickness of the tube wall. Copper tubing for supply lines comes in three wall thicknesses, designated by the letter K for the thickest, L for medium, and M for the thinnest. Unless specified otherwise in your local building or plumbing code, M is usually considered adequate for home water supply systems. Copper drainage tubing comes in DWV thickness as rigid tubing only and only in the larger sizes used in DWV systems.

Another attribute of copper that can save you money is its superior water-carrying capacity. Because of the interior smoothness of both the tubing and the fitting connections, you can often use one size smaller pipe than with iron pipe and retain the same water flow.

The fittings for copper tubing are similar in most ways to those of iron pipe. There are ells, tees, crosses, couplings, and reducers. In addition, there are adapters to connect the end of a threaded pipe to a copper tube.

All three types of copper tubing are 0.875 inches (7/8”) outside diameter. The inside diameters are: K = a little less than 3/4’, L = about 25/32”, M about 13/16”.

Female adapter; Male adapter; Flare fittings; Coupling; Female adapter; Male adapter.

Ill. 33 -- Bending and Cuffing Copper Tubing: Tubing cutter; Cut here

The best way to fit tubing around a turn is to temporarily place the fittings, bend the tubing, and then to fit.

Slip the tubing into a tubing bender and apply hand pressure until It’s bent as you want it.

To cut the tubing, twist the knob so the cutter wheel pierces the surface of the tubing a little and then rotate the cutter around the tubing. Repeat the process several times until the tubing is severed.

Bending Copper Tubing

Flexible or soft tubing, especially in the smaller diameters, can be bent without a tool if you are very careful and don’t try to bend it too sharply, To be sure that your bends are without kinks or flattened spots, it's much better to use a tubing bender. A thin-walled tubing bender is a tube made of a tightly wound coil of hardened spring steel. It is usually about a foot long and comes in a range of diameters to accommodate the most common sizes of tubing. Just slip the tubing into the bender of the proper size and apply pressure by hand until the bend is as you want it, There are other styles of benders with grooved wheels and handles, but the wire-spring tubing bender is the simplest and is accurate enough for the smaller sizes of tubing.

Measuring and Cutting

Measuring a length of copper tubing is in some ways easier than measuring a length of iron pipe. You still must measure the length between the faces of the fittings and add the amount of pipe that will go into the fitting. With copper tubing, however, you can actually slip the fitting onto the pipe to help you measure accurately.

If you are working with flexible tubing, it's a good idea to route the tubing where you want it before cutting. Just secure the starting end temporarily—insert it in a fitting or have a helper hold it—then take it over, under, and around to where you want the other end. You can usually even thread it through holes if necessary without cutting, especially if you have someone help. When you reach the place you want the end to be. hold a fitting against the tubing, mark it with a pencil or crayon, and cut it. It is usually a good idea to cut the tubing a little long for added flexibility in the final placement of the tubing and its supports.

Tubing can be cut with a hacksaw, but a tubing cutter is much quicker, easier, more accurate, and not very expensive. A tubing cutter works just like the pipe cutter described. Turn the handle to adjust the cut ting wheel so it just rests on your mark. Turn the handle enough to press the cutting wheel into the tubing and rotate the cutter around the tubing. Repeat the process several times until the tube is cut off. The first cut or two will give you a feel for how much to turn the handle each time. Don’t apply too much pressure or you will distort the tubing. When the tubing is cut, remove the burr around the inside with a reamer. Almost all tubing cutters come with a retractable or fold-away reamer built in.

If you must use a hacksaw, get a fine-tooth blade. 32 teeth per inch, and a small miter box. Be sure you make your cut smoothly and squarely across the tubing. Use a reamer or small round file to

Joining Copper Tubing

There are several ways to join copper tubing. Sweating, tinning, and swaging are all used on rigid tubing and can be used on flexible tubing. Flare and compression joints are used only on soft flexible tubing.

Sweating. Sweating is a method of soldering that makes a very strong joint between copper tubing and fittings. If done right, the joint will be stronger than the tubing itself. Sweating is an easy process, but it does take a little practice to develop a feel for the proper temperatures.

Just a word of caution before you begin. If you are working on an existing plumbing system that has had water in it, open at least one nearby faucet and leave it open until you finish soldering. Even a few drops of water in the tubing you heat will turn to steam and expand greatly. If the part of the system you heat has no opening, the steam pressure could make one by bursting a tube and possibly injuring someone nearby.

If you are working within a few inches of a valve or faucet, take it apart and remove the washer and any other nonmetallic parts. The heat from your torch can melt, burn, or distort these parts if you don’t. Also be sure that the fitting and the tubing have good support when you solder, Do not attempt to hold either in place with your hand. Even if you hold the tubing a foot or more from where you apply the heat, you may get burned.

To sweat copper tubing, you will need fine emery cloth or steel wool, a container of noncorrosive paste flux and a b to apply it, lead-free solid solder wire, and a propane torch. Use the emery cloth or steel wool to clean and brighten the end of the tubing and the inside of the fitting. Apply a thin coat of flux to both brightened surfaces and slip the tubing into the fitting. Rotate them to distribute the flux evenly and wipe away any flux that has oozed out of the joint.

Evenly heat the fitting and the tubing near it with the propane torch, moving the torch back and forth and around. When the flux bubbles and smokes a little, remove the heat and quickly touch the end of the solder wire to the joint. If the fitting and tubing are the right temperature, the solder will melt and be sucked evenly into the joint by capillary action. The capillary action will even suck it upward if that's the way the fitting is positioned. If the joint isn’t hot enough, the solder won’t be sucked into the joint. If you use too much heat, especially more heat after you’ve applied the solder, some of the solder will run out of the joint. In either case, the best thing to do is to heat the joint to melt the solder, pull it apart, and start all over. Once you have a smooth line of solder all around the joint, it's filled and finished. Let it cool and go on to the next joint. If you are in a hurry, you can wet the joint with water to cool it, but don’t touch or move anything until the solder loses its shine and you’re sure it has hardened. This should only take ten seconds or so even if you don’t wet it, but it will still be very hot to the touch.


When working with a torch in tight places. always have a piece of sheet metal or asbestos handy to protect the wood from the flame. It is also a good idea to have a plant sprayer or bottle of water to wet down any wood you may scorch. Always recheck and rewet any charred wood before you leave for lunch.

Sweating Copper Tubing

ill.34 1. After cutting, remove burrs with the reamer on the cutter or with a file. Polish the outside of the tubing and inside of the fitting with emery cloth or a wire brush until it’s bright.

2. Apply a thin layer of flux to the polished areas.

3. Push the parts together and twist to distribute the flux evenly.

4. Heat the fitting evenly with a propane torch until the flux bubbles.

5. Remove the heat and touch the solder to the hot joint where the tubing enters the fitting. The solder will be drawn into the joint.

6. Wipe clean with a rag.

ill.35a Swaging

ill.35b Flare Joining

Tinning. This method is used when you are working on pipe above your head, like in a crawl space, and are afraid that dripping solder or hot flux will fall on you. Brighten the surfaces just as you would for sweating and apply the flux. Then heat each piece and apply the solder wire so you cover the contact areas thinly and evenly — cover both the outside end of the tubing and the inside of the fitting. Let each piece cool.

Then press the fifing into the tubing just enough to hold it. Apply pressure to the fitting or the tube, which ever is easier, with a board or pair of long-handled pliers as you apply heat. The instant the solder reaches melting temperature, the pieces will slide together with little chance for hot solder or flux to drip out. Remove the heat quickly as soon as you are aware that the solder is melting. Swaging. This is a way of joining two pieces of thin- walled copper tubing without a fitting. In making a swaged joint, you expand one piece of copper tubing so another piece can slide into it. You will need a special swaging tool for this, and each size of tubing needs its own tool. Swaging tools usually come in sets for several common sizes of tubing. To form a swage joint, you place the swaging tool at the end of a piece of tubing and drive it in with a hammer or with a screw-down mechanism similar to a flaring tool. When you remove the tool, the tubing has an enlarged end just the size of a regular copper fitting (see the drawing). Now you are ready to sweat or tin the joint.

Flare Joints. A flare joint can only be used on soft flexible copper tubing and only where the joint will not be concealed within a wall. Flare fittings aren't usually recommended for extensive installations, but are useful in places where you might not want to use a propane torch. They are often used to connect fixtures or appliances that can be replaced easily at some future date.

To make a flare joint, you will need a flaring tool and the necessary fittings. Cut and ream the tubing as you would for a sweated joint. Slip the flange nut, the female part of the fitting, over the end of the tubing to be flared with its threaded end toward the end of the tubing. You won’t be able to put it on the tubing after it's flared. Flare the end of the tubing with the flaring tool. Slide the flange nut against the flare, hold both against the male threads of the other part of the fitting, and screw the nut on as tightly as you can by hand. Then tighten it with two smooth-jawed wrenches and test it for leaks.

Compression Joints. This joint is similar to a flare joint, but you need no special tools, It uses a rubber, plastic, or metal compression ring instead of a flare in the end of the flexible tubing. Cut the tubing as usual, slide the flange nut and then the compression ring onto the tubing. Hold the flange nut and compression ring together at the end of the tubing and put the flange nut over the male end of the other part of the fitting. Tighten it with your fingers and then with two smooth-jawed wrenches.

1. Slide the flange nut onto the tubing.

Flaring tool

1. Slide the tool into the tubing, then hammer it to expand the end of the tubing.

Copper tubing

2. Put the end of the tubing into the flaring tool and tighten the wing nuts.

3. Attach the ram to the flaring tool and screw it into the end of the tubing to make the flare.

2. Slip a length of regular tubing into the swaged end and sweat the two together as you would any soldered fitting.

4. Place the male end of the fitting against the flared end of the tubing and ...Regular tubing

5. screw the flange nut onto it.

You won’t often need elbow fittings because the flexible tubing bends around corners. Other than that, flare and compression fittings come in all the usual configurations—tees, wyes, crosses, reducers, and so forth—us well as shutoff valves and other items.

Repairing Copper Tubing

A small pinhole leak in a copper tube or pipe is easy to repair with solder. Turn off the water and drain the line. Be sure to leave a faucet open in the line you are working on. Clean the area around the leak with emery cloth or steel wool. Apply a coat of flux. Heat the defective area with a propane torch and apply a dab of solder over the hole. This is only satisfactory for a very small hole—water pressure will pop the solder from a large hole.

For larger leaks, cut the tubing on each side of the hole. If the tubing can be bent or moved enough, clean and flux the ends and join them with a sweated-on coup ling. If the ends can't be pulled together, cut a small piece of tubing to fit between the ends and use two couplings.

It isn't possible to solder any joint with water in it, even the slightest trickle or drip. In the event that closing the valves doesn’t shut the water off completely, stuff a piece of bread into the tubing and push it several inches above where you want to solder. This temporary dam will hold back the water long enough for you to solder the joint and then will dissolve and wash away com pletely when the water is turned on.

One or more compression unions can be used in stead of sweating on couplings if soldering isn't desirable.

ill.36a Compression Joining: 1. Slide the flange nut and then the compression ring onto the tubing. 2. Insert the tubing into the fitting. 3. Holding the nut and ring together, screw the flange nut onto the fitting.

ill.36b Repairing a Large Leak in Copper Tubing: 1. Cut out the leaking section of tubing. OR 2. If the ends won’t come together, Insert a section of new tubing and sweat on two slip couplings. OR 2. If you prefer not to make sweated joints, insert a compression union. Flange nut, Fitting, Flange nut, union, Slip coupling

ill.37 Tools for Copper Tubing: Tubing cutter, Propane torch, Solder wire, Swaging tools

Tools for Working with Copper Tubing

Tubing bender. Here you can choose between two types. We prefer a set of the tightly wound spring steel benders. They usually come in a set of six for bending ¼-, / ¾-, / ½-, and 5/8” thin-walled tubing. You just insert the tubing into the bender and bend it however you want by hand. You can bend the tubing to a small or large radius just by how you manipulate it with your hands.

The other type of bender has a groove for each size tubing around a cylinder about 2 inches in diameter. You can bend the tubing as much or as little as you want, but the diameter of the bend will always be the same as the cylinder of the tool.

Tubing cutter. Using this tool is by far the quickest, easiest, and neatest way to cut tubing. Most types come with a reamer attached.

Steel wool, wire brush, or emery cloth. You’ll need this to polish the surface of the copper for sweating. Because it conforms to the shape of the surface better, we think steel wool does a better job than emery cloth. It is less expensive, too.

Propane torch. The best kind to get is just a nozzle with a flame-adjustment knob that screws to a propane cylinder. This torch is great for thawing frozen metal pipes ii it's fitted with a flame spreader, The spreaders are often sold with the torch.

Solder wire. Use solid solder wire that's labeled lead- free for joints in any system that supplies drinking water. For other applications use a solder that's acceptable to local building codes. The solid wire does not have a core of acid or rosin—for sweating copper it's befter to apply paste flux yourself with a brush.

Noncorrosive flux and a brush. The main purpose of flux is to prevent the metal from oxidizing when heat is applied. This gives the solder a firm metal surface on which to adhere. It also cleans old corrosion from the metal if you missed some with the steel wool. The brush makes the job so much easier that it's well worth the few extra cents that it costs.

Sheet of asbestos or metal. This is to place behind the tubing you are sweating to prevent the torch flame from igniting the studs or joist behind the pipe. You only need this protection if you are soldering within 6 inches or so of the wood, Swaging tool. This tool shapes the end of copper tubing so it will slide over the end of another tube of the same size. It isn't often used by the homeowner for small jobs.

Ball peen hammer. You’ll need one of these if you opt to use a swaging tool. It has a different temper than a carpenter’s hammer and is much less likely to chip when used to hammer on metal.

Flaring tool. You’ll only need this if you prefer making copper tubing joints without solder. It flares the end of a copper tube so it can be held by special solderless fit tings. (This tool, along with standard flare fittings. can also be used to conned CPVC and PB plastic pipe to a metal pipe system).

Wednesday, May 9, 2012 2:40 PST