How to build a demand feeder. A simple demand feeder can be made with a 5 gallon bucket, a funnel, brass rods and PVC pipe. It can hold 12 pounds of extruded (floating) fish feed. Use a typical 5 gallon bucket, approximately 10.5" bottom and 11.5" top diameter x 14" high. Drill a hole in the center bottom with a 2" diameter hole saw. Use a plastic funnel with a top diameter of 11". (Cole-Parmer U-06121-20 http://www.coleparmer.com/ ) Trim the bottom tip from the funnel leaving an opening 1" diameter. If necessary trim the top lip of the funnel down inside the bucket so that it fits snuggly while the tip of the funnel protrudes slightly from the buckets bottom hole. Drill a ¼" hole through the side of the funnel about 3" from the tip of the funnel. Drill a second ¼" hole exactly opposite this hole on the other side of the funnel. Use a 6" section of ¼" brass rod. Use a die (1/4-20) to cut thread into the first 1 inch of each end of the rod. Use a 1/8" drill bit to drill a hole through the center of the rod. Use a 18" section of ¼" brass rod. Use a die (1/4-20) to cut thread into 5" of one end of the rod. Use a 1/8" drill bit to drill a hole through the rod, about 1/4" from the top of the threaded end. Use a hole saw with pilot bit to cut a 2" round disk from a ¼" thick piece of plexiglass. Thread a brass nut down the 18" section of brass rod. Push the plexiglass disk down the rod to the nut. Thread a second brass nut down the 18" section of brass rod. Open the key ring and thread it through the hole in the end of the brass rod. Insert the 6" section of brass rod through the drilled holes in the side of the funnel. Thread a brass nut on both ends of the rod to secure it in place. Be sure to center the drilled hold in the brass rod over the bottom hole of the funnel. Insert the funnel into the 5-gallon bucket. Be sure it fits snuggly, straight and level inside the bucket. Insert the long brass rod into the bottom hole of the funnel. Open the key ring and thread it through the hole in the center of the brass rod. Apply a bead of silicone caulk around the top lip and the bottom tip of the funnel to seal it to the bucket. Allow to dry 1 day.
Adjust the 2 nuts on the long brass rod so that there is a ½" space opening between the bottom of the funnel and the plexiglass disk. The plate is adjustable to allow for different sizes of feed and to assist in training the fish to the feeder. A wider opening allows easier discharge of feed and can be narrowed as the fish learn the operation of the feeder and hit the rod harder. It can also be adjusted to adapt to different water conditions - turbulent water can rock the rod and spill feed it the adjustment is too wide. Part list: 5 gallon bucket 11.5" diameter x 14" high 11" diameter funnel (Cole-Parmer 6121-20) 6" x 1/4" brass rod 18" x ¼" brass rod ½" diameter key ring 2" diameter Plexiglass disk Silicone Tools: Drill Drill bit ¼" Thread cutting die ¼-20 Knife 2" hole saw
The finished product center Bucket with 2" hole in bottom
Funnel with rod. ends and center hole. 6" Brass rod with threaded
plexiglass disk and key ring. 18" rod with threaded end, Disk and keyring detail.
6" brass rod in place. Funnel inserted in bucket with brass rod connection detail. 6" brass rod, key ring, and 18"
Building a stand. For outdoor use or on a floating cage where overhead suspension is not available a PVC stand can be made to support the feeder. Use 1" PCV pipe with 4 90 elbows and 4 "T" couplings. Cut 4 lengths of pipe 11" long each. Cut 4 lengths of pipe 8" long each. Cut 4 lengths of pipe 15" long each. Assemble a rectangle with the 8" sections as the ends and with the 11" + 8" + 11" lengths as the sides. Use the elbows at the corners and the T along the sides to connect the 3 pieces. Arrange the Ts pointing up. Insert these lengths into the Ts. Assembly The demand feeder bucket slides into the 4 upright PVC sections. Drill ¼" holes through the uprights and into the bucket at about 4" from the bucket top. Attach the bucket to the stand with bolts. Demand feeder stand detail.