John-Edmonton
Silver Member
- #1
Thread Owner
Sometimes the laws of physics are at play without us even being aware of them. For instance, if you take a plastic sealed container, put a small pin hole in it and submerge it hot water, you will notice shortly that air bubbles will start to leak out under pressure, simply because the inside temp is warming up, causing a positive pressure.
Now reverse the conditions. Warm the plastic container up, and place it in cold water. What happens? The cooling of the temperature caused a low pressure or vacuum to appear inside the container, and in order to reach an equilibrium, it sucked in water.
Watch how hot your equipment is before you submerge it in cold water. A metal detector in the car trunk or in the car with the sun shining on it will cause it to get extremely hot. By putting it in the cold water, you are causing a tremendous amount of vacuum to be produced as the the inside of the coil, connector or electronics box tries to reach an equilibrium of pressure. Create enough vacuum in the coil, connector, splicing, electronics and you might get some leakage. Please......cool your equipment off before suddenly submerging it in cold water. This is true for all makes and models of detectors. Although leaks can occur for many other reasons, this should surely help.
Now reverse the conditions. Warm the plastic container up, and place it in cold water. What happens? The cooling of the temperature caused a low pressure or vacuum to appear inside the container, and in order to reach an equilibrium, it sucked in water.
Watch how hot your equipment is before you submerge it in cold water. A metal detector in the car trunk or in the car with the sun shining on it will cause it to get extremely hot. By putting it in the cold water, you are causing a tremendous amount of vacuum to be produced as the the inside of the coil, connector or electronics box tries to reach an equilibrium of pressure. Create enough vacuum in the coil, connector, splicing, electronics and you might get some leakage. Please......cool your equipment off before suddenly submerging it in cold water. This is true for all makes and models of detectors. Although leaks can occur for many other reasons, this should surely help.
I'm aware of the hot/cold air volume effect and have demonstrated it to my kids while washing out plastic water and soda bottles... but I never thought of how it would impact a "waterproof" detector or coil. 
