COPPER PIPE

How To Figure And Cut Copper Tubing

The same kind of mathematics applies to determining the proper length of cuts for copper tubing as is used in galvanized pipe. Each size of tubing has a set of specifications for the various fittings.

From these, a fitting allowance can be computed. and the length of cut adjusted accordingly. Copper tubing is easily cut with a cutter and should be reamed to make sure the inside diameter is not reduced at the joint and that all burrs are removed.

"Hard" Copper Tubing

"Hard" copper tubing is also commonly used for original plumbing. Joints are made by soldering fittings into position. As always, local codes should be followed. The tools needed to make installations using "hard" copper tubing are: cutter, reamer, torch, pliers, wrenches, measuring tape, flux, solder (lead free), level, emery cloth or emery paper, and steel wool.

• While the solder is still hot and fluid, remove any excess solder with a small brush or rag.
• Support the new joint until the solder hardens. A wet rag can be applied to the joint to speed cooling and hardening of the solder.

  When applying heat to copper fittings for the purpose of sealing a joint, be sure to insulate plastic components, control valves, bypass valve seals and other heat-sensitive components. Copper is an excellent conductor of heat which may travel a considerable distance from the point where the sealing joint is being formed. To protect your system, wrap a wet cloth around the copper pipe between the joint and the heat-sensitive part. The wet cloth will keep the pipe cool enough to prevent damage. If a wet cloth cannot be used (often the case when installing some byass valves), those parts that may be damaged by heat will have to be removed until the heating process is completed.

"Soft" Copper Tubing

Annealed or "soft" copper tubing should be avoided whenever possible as it is much more subject to physical damage, it kinks readily when being bent, and rarely results in a sound, neat installation. It should only be used when absolutely necessary because of physical clearances or unusual bends, Even then, the full diameter should be maintained. As always, local codes must be followed.

Soft copper tubing comes in rolls, and joints are made by flaring the ends of the tubing and using threaded brass fittings Tools required are cutter, reamer, flaring tools, pliers, wrench and measuring tape. Figuring lengths of cut is much less critical with soft copper since it can be bent to adjust for slight excesses in length.

When creating a joint for soft copper, be sure to slip the fastening nut over the tubing before inserting the tubing into the flaring tool. The threaded end of the nut should be facing the flaring tool. Then proceed to flare the end of the tubing.

Pipe Measurements

In order to "come out even," an installer must he able to figure lengths for the piece of pipe to be used in running from one point to another. To do this, allowances must be made for the length of threads, the size of the fittings. etc.

Each size of pipe has a set of specifications to cover all fittings available. For example, with 3/4" pipe, the standard thread engagement for all fittings is 9/16". This means that when a length of pipe is tightened securely into a fitting, 9/16" of the length of pipe will be inside the fitting. In other words, the pipe must be 9/16" longer at each end than the measurement between the faces of the fittings.

Consider an installation where the pipe runs vertically, then horizontally for five feet, and then back down again, 60" between the centerlines of the two vertical pipes.

To calculate the length of the horizontal piece of pipe, first, figure the fitting allowance for an elbow. This is the distance between the end of the pipe, inside the elbow, and the intersection of the centerlines of the two pipes. Do this by checking the specifications and determining the standard dimension of an elbow for the distance between the intersection of the centerlines and the face of the elbow.

The fitting allowance is 3/4". The length of pipe must be reduced by 3/4" for each elbow that is included in the five-foot run you are making. This is because the distance from the end of the pipe, inside the fitting, to the intersection of the centerlines is actuallv 3/4".

Since there will be two elbows, subtract 1- 1/2" (2 x 3/4") from the theoretical 60'' run, which makes the pipe length for cutting 58-1/2" long. Each end will be threaded 9/16" into each of the two elbows. Follow the same procedure for all fittings to determine actual lengths of pipe.

Cutting Pipe

Although it is possible to make cuts that are "square" or perpendicular to the centerline of the pipe with a hack saw, pipe is easier to cut with a pipe cutter. In order to properly thread galvanized pipe, a square cut is necessary. When cutting pipe and when cutting threads with a die, a pipe vise should be used to hold the pipe. After cutting the pipe, the end should be reamed so that the inside diameter is full size and no burrs remain.

When cutting threads, cutting oil should be applied three or four times. This reduces the heat which is generated by the cutting die and prevents threads from being torn. It also keeps the dies from becoming dull prematurely. When the end of the die is even with the face of the pipe, the threads are cut to standard length.

Before engaging threads in the fitting, they should be cleaned of chips and burrs and then wrapped with pipe thread tape or coated with pipe dope (pipe joint compound). Only the male threads should be coated.

How To Tighten A Fitting

Engage the threads of the pipe and the fitting and tighten by hand until they are tight. Then place a wrench on the bead of the fitting and turn about one turn. Two turns may possibly be required, but no more. PIPE OR FITTING GOUGING CAN BE MINIMIZED BY NOT CHANGING THE POSITION OF THE WRENCH. Too much tightening may expand a fitting so that it will leak and have to be replaced. Brass fittings are more likely to expand than steel fittings. Use a wrench that is properly sized for the diameter of pipe being installed.