Whirli I recognized what this was before i read it because of that backwoodsman issue. That was a great article.
Free as for boilng the wife, that’s why i always test any water temp with my toe before i get in lol.
The coil principle has so many different applications. It is actually a similar design used in tankless hotwater heaters. The coil is heated to a very high temperature with natural gas or propane in an insulated box. When the water is turned on the only water that is not hot is the water that is in the line between the coil and faucet.