Fixing Leaky Pipes
The easiest method for repairing a leaky pipe without disassemlbing the entire system.
A welding epoxy (such as J.B. Weld)
A stirring/application stick
Soap, water, and a sponge
Sometimes, a pipe will develop a leak (either through the ravages of time or through physical damage), but the task of replacing that particular section will be a truly monumental task. In these cases, you can often make an equally effective solution by sealing the leak in the pipe, rather than replacing it. The major advantage to this is avoiding the disassembly of the entire system (be it a car engine or your home plumbing). Remember that this method is designed for metal pipes. While a metal epoxy might do some good for a PVC pipe, it is not suggested.
Drain the pipe
Whether you intended to fix a leaky pipe or replace it, you will still have to drain the pipe of whatever liquid runs through it. This applies to your home plumbing as well as your car engine. Keep in mind that you will not be able to run fluid through the pipe until the epoxy has hardened.
Clean the surface
In order for the epoxy to take hold and seal your pipe, you will need to make sure that the surface is clean and dry. So, make sure that any fluid has finished draining from the inside of the pipe and then wash off the exterior. Clean off all exterior dirt, grease, or other grime.
Sand the surface
Take your sandpaper and rough up the surface of the pipe. By doing this, you will create more surface area, which provides the epoxy with a better hold. Clean the surface again when you are done sanding.
Mix the epoxy
Welding epoxies, which can be purchased at any automotive supply store, come in two parts: a tube of steel resin and a tube of steel hardener. Squeeze an equal amount of each onto a clean paper plate or piece of paper. Take your mixing stick (chop stick, plastic knife, whatever you have) and mix the two together until you have a solid grey substance.
Add the epoxy
Using the mixing stick, spread the epoxy onto the cracked pipe in a clean, smooth layer. Make sure that you have covered the entire damaged area and left no holes, cracks, or spaces in your epoxy.
Allow it to dry
The epoxy will now need about four hours to harden. Do not touch it until it is complete. Although the epoxy is now a solid, you should still avoid running anything through the pipe (or running your engine if this repair is being made upon a car) until it has hardened through the night. After sixteen hours, the pipe should be ready to go. Use it and throw a party to celebrate all of the money you didn't have to pay someone to take your entire system apart and replace the pipe.
1) Drain the pipe
2) Clean the surface
3) Sand the surface, clean it again
4) Mix the steel resin with the steel hardener
5) Apply the epoxy to the pipe
6) Allow to dry overnight before using