Blacksmiths have traditionally used hand crank blowers to increase airflow and make their fires hotter. These devices serve as air pumps with enclosed chambers that have both inlet and outlet valves to control the amount of air delivered with each puff. They have parallel sides joined by expansible material that allows it to contract and expand when operated. A long handle affords safety to the operator by keeping a good distance from the hot flames. Materials traditionally used by blacksmiths include fabrics, leather and wood. You can construct your own blower using materials that are commonly available.
Lay out plywood sheeting on a flat surface and mark the shape for the outline of the blower body. Draw an oval shape that is 12 inches long, 6 inches wide at one end and tapers to a 2-inch tip. Cut the wood and then use it as a mould for a second piece of equal size. Drill a 1-inch diameter hole on the wide part of one of the body pieces. Sand down edges until smooth. Leave the wood plain or stain to suit your preferences.
Drill a hole completely through the centre of the 2 by 2 cube. Make it just wide enough to accommodate the PVC tubing. Sand the exterior of the cube to remove rough spots. Stain if you prefer. Insert the tubing through the hole. Secure the seal with epoxy glue. Insert tubing through the hole in the body segment in the same manner.
Attach flat hinges to two opposite ends of the square block using appropriately sized nails. Connect the open end of each hinge at the edges of each body segment at the tapered end. Wedge open the blower body to about 8 inches to demonstrate the maximum opening of the air compartment for this design.
Position half of the blower apparatus on the vinyl and draw the outline. Use a ruler to measure 10 inches from the wide end, and a distance of 4 inches from the tapered end. Mark a short line on the vinyl to note those measurements. Connect the lines to form a larger and wider outline. Cut along lines for both the original pattern and the wider line and cut a straight line across the tapered base.
Glue one end of the vinyl to the inside of the blower using epoxy glue. Glue the other end to the inside of the opposite panel. Allow to dry before using.
Fix the 1-inch timbers on top of the widest part of the blower body to serve as handles. Secure using epoxy glue.