How I made simple water heaters, so far no ice at -14 F. using plastic or metal fonts. I made 6 chicken water heaters. At 46 degrees below zero Celsius they were ice free. https://www.backyardchickens.com/forum/uploads/70090_water_heaters_009.jpg https://www.backyardchickens.com/forum/uploads/70090_water_heaters_005.jpg https://www.backyardchickens.com/forum/uploads/70090_water_heaters_008.jpg https://www.backyardchickens.com/forum/uploads/70090_water_heaters_003.jpg https://www.backyardchickens.com/forum/uploads/70090_water_heaters_010.jpg Heat gets directly to plastic not to tin then plastic. I tested this one dry for two hours in the house at 40 degrees Celsius, no melted plastic. 1-cut hole in top, use extension cord, attach plug socket, 60 watt bulb, insulation holds socket and bulb in place. 2-added foil to reflect heat, added four eye bolts and rubber cords. 3-hole for extension cord. see how much wider the tin is than the font. cut hole in top allowing full support of red trough. hot edge of lid keeps the trough warm and frost free. the smaller tins will keep tank warm, but the trough will frost up or freeze. I use the taller tins to keep fount clean. this one is for Silkies. You can hang this font, the rubbers will support the weight keep the heater and font tight together. my dw came up with many suggestions and ideas. also thanks to henney penny and her dh, post 100550 and brooky, post 107951. regards, Bob.