Have you ever walked down the plumbing aisle at your local building store and wondered why they have so many different types of teflon tape and pipe joint compounds? If you're like me, then probably not, because frankly it's a really boring aisle to walk down. Well for anyone doing any DIY plumbing, let me tell you it does actually pay to stop in this aisle and learn a thing or two, about a thing or two.
Here's what i learned:
1. No matter how much you think you might be saving, don't ever buy the cheap teflon tape. There's a very good reason why some rolls cost 4 bucks and others cost 39 cents.
2. Get some pipe joint compound, and make sure it is safe to use for your application.
3. Shut off valves are your friend.
A few weekends ago i was replacing the shower valve in our basement bathroom. The valve uses threaded fittings to connect to the copper supply lines. So i went and shut off the water and waited while the whole house drained. Then i soldered some brass fittings to some short copper pipes. And using some teflon tape i found at the bottom of my tool box, i threaded the fittings into the valve good and tight. Using a copper coupler, I then soldered the supply lines to the short copper pipes to complete the connections. I was now ready to turn the water back on to make sure i didn't have any leaks. To my surprise the threaded fittings were dripping water, i thought i had tightened them as well as i could without damaging the threads. Of course once the whole assembly had been soldered together the only way to unthread the fittings is to turn off the water, drain the whole system, cut the copper pipes and start all over again. After 2 failed attempts, i was ready to turn the 3-piece washroom into a 2-piece. I had spent an entire day without water and i couldn't turn the water back on until everything was water-tight. My wife wasn't very happy with me.
So here's what i did. First i installed inline shut off valves way above the shower valve, so i could turn the water back on to the rest of the house. And so i could turn the water off just in the area i was working on, when i ever decided to make a third attempt. This would save me hours of waiting for the system to completely drain. These shut off valves would eventually get buried in the wall so they didn't have to be pretty. I turned to the internet to try to figure out why no matter what i did the threaded joints wouldn't hold water. And here's the secret - BUY PROPER TELON TAPE, YOU IDIOT!
Anyhow, i will now share my surefire way to creating a water-tight brass threaded joint.
1. Make sure the threads are the same size, and both the male and female threads are clean and burr free.
2. Put 2 wraps of good teflon tape on the male threads. I like the orangy-pink stuff.
3. Put some pipe joint compound on the female threads (make sure it's non-hazardous for household water, you don't want to drink or shower in poison).
4. Hand tighten till you feel a noticable increase in resistance.
5. Wrench tighten 2 more full turns.
And voila no more drips: