I'm doing my Product Design homework and have gone blank. After soldering a joint in copper, do you have to allow it to air cool or do you dunk it in water to cool it?If anyone knows I'd be grateful, thanks.
either will work, mostly air cooling is used as it is more convenient. You can't solder a joint in two water pipes and then dunk the pipes into water, they are attached to the wall. The big point is not to allow any relative movement between the two pieces while it cools. .
The usual reason to cool a copper pipe joint is to be able to wipe it and remove any excess flux so as to not leave a residue that will corrode. Moving too quickly with the damp cloth will crystallize the still fluid soldering media and ruin the joint. Cooling a pipe at some distance from the solder joint is sometimes done to avoid melting or burning something close to the joint.
never dunk the copper pipe into water,let it air cool. When you dunk it you shock the 400 degree solder and crack the solder joint bad bad bad that's when they blow out. Im a licensed plumber pipefitter and welder, I have seen what happens when hack plumbers do this and you air test or hydro test a system for inspection. Unless you want pin hole leaks after a few days or just a cataclysmic blow out don't dunk it. A nice and easy way to clean the black burnt flux like the other persons talking about is not to burn the joint your heating it up too much, if you have burnt flux on the outside of the pipe i can guarantee u have a flux pocket at least the size of a pencil eraser inside the cup. Wipe your joint with your gloves when its still hot. AND DO NOT DUNK IT
In most cases the solder will solidify so quickly you wouldn't have time to dunk it. You could do it just to cool the residual heat for ease of handling, but wouldn't matter much.
