Years ago we had a small craftsman air compressor (had the two wheels and handle to pull it tank looked like a 30 lb propane tank).We would have to make a copper coil from the compressor coiled so you can put the coil in a 5 gallon bucket with water then back to the tank to prevent water getting in the air even with a filter ,the compressor would run constant but kept up and after you would have a bucket of hot water
