water heater drain plug
so we are getting the MH ready for our trip after storing it for 3 years.... and open the outside door to the water heater. saw the gungky old drain plug sitting there - loose. when we put the new on...
Forum Discussion
A "tap" is a tool bit that creates threads inside a hole. 
Plumbing uses different diameters and threads-per-inch than nuts and bolts, so "pipe tap." Notice the pipe tap is tapered. If you use a pipe tap to clean up rusty threads, do NOT turn it till you are cutting metal! ONLY remove Rust/Corrosion! Go too deep and your Plug, also tapered, won't find bottom and will leak.
There's a tap-like "thread chaser" which is designed to only clean threads but not form them. Harder to damage threads with a chaser.
You can make a Chaser. Get a shortish (say 4- to- 6-inches) Pipe Nipple. Short piece of pipe threaded both ends. File grooves through the threads, down to the solid surface of the pipe. These would be parallel to the length of the nipple (perpendicular to the threads). About three will do. Then thread the home-made chaser into the plug hole. The edges of the grooves will cut the rust loose and leave it in the groove. Twist it in and back it out a few times. Should get the threads clean enough to get the plug back in. Get another plastic plug if it's an Atwood heater. Brass starts an electrolytic fight with aluminum and aluminum loses. No need to put steel in there and have more rust.
Plumbing uses different diameters and threads-per-inch than nuts and bolts, so "pipe tap." Notice the pipe tap is tapered. If you use a pipe tap to clean up rusty threads, do NOT turn it till you are cutting metal! ONLY remove Rust/Corrosion! Go too deep and your Plug, also tapered, won't find bottom and will leak.
There's a tap-like "thread chaser" which is designed to only clean threads but not form them. Harder to damage threads with a chaser.
You can make a Chaser. Get a shortish (say 4- to- 6-inches) Pipe Nipple. Short piece of pipe threaded both ends. File grooves through the threads, down to the solid surface of the pipe. These would be parallel to the length of the nipple (perpendicular to the threads). About three will do. Then thread the home-made chaser into the plug hole. The edges of the grooves will cut the rust loose and leave it in the groove. Twist it in and back it out a few times. Should get the threads clean enough to get the plug back in. Get another plastic plug if it's an Atwood heater. Brass starts an electrolytic fight with aluminum and aluminum loses. No need to put steel in there and have more rust.
