Do not attempt to bend tubing by hand or around a pipe or pole. Unless the tubing is supported around its circumference, it will flatten at the bend and possibly crack, causing it to leak. Use a tool called a bending spring shown here in figure 27 on the right.
The bending springs are inexpensive and do the job properly. Place the spring over the tubing at the area to be bent, then bend it slowly and carefully, making a curve as large as practical. The larger the bend, the less likely it will be flattened or kinked. Never try to complete a curve in one stroke. Do it in short stages until the appropriate curve is made. Remove the spring by twisting while sliding it off.
For tubing larger than one-half inch in diameter, a bending lever with a flange attached to the end is used. (See illustration below.)
Spring-type benders (upper right) make it easy to form bends by hand without collapsing the tubing. They can also be used to protect tubing during installation and repair procedures. The special coil spring wire easily slips over the outside of the tubing, and the belled end simplifies insertion and removal.
The lever-type tubing benders illustrated on the left are used for the larger sizes of tubing as they require considerably more effort to bend. The curved radius on the stationary bar has a scale in degrees. When the movable lever bends the tubing, its index mark indicates the degree of the curve. The lever type shown at the lower left has no scale, and the bend must be judged by eye or separate measurement.