How To Make PVC Train Horns at Home ~ Roadkill Customs These simple homemade PVC train horns are based off of dozerboymiller’s horn design. The horns are made with three reducers, the diaphragms are cut from a Tupperware storage container that’s about an eighth inch thick. There is an air line powering both the horns that comes off of a scuba tank. The horns are tuned to a third apart. Easy PVC Fog Horn - instructables Both horns are operated using a large manual air pump in the video, though they can also function using compressed air or simply by blowing into the inlet with lung power. If high pressure air is used it might be necessary to find a more durable diaphragm.