Hot water heater drain

Run a tap in till it just begins to cut metal, this ain't that difficult. Just be careful starting the tap, in the hands of an amateur it is easy to get it cross threaded.

I would not use a standard pipe tap on the threads, turning that tap past the point where the corrosion inhibits fully inserting the tap will eventually remove metal as well as corrosion. If you ever see the thread cutters in both a tap and a die, you will notice that there is a little space left in the valley between the cut of the two. the sides of the threads are supposed to mate not the entire thread. That little valley is where the corrosion gathers and make fitting the two pieces together difficult.

A medium hard brass brush mounted in a rotary tool is about the best solution. A bore cleaning brush from your local gun shop is probably among the best you could buy. Even then care in use should be taken. In an Atwood water heater, extreme care must be take when using a rotary brush. A chemical solution is best in that case.

I have used the nipple with groves cut perpendicular to the threads on several occasions and when used in conjunction with a chemical agent is pretty good.

There are a lot of chemical cleaners available for dissolving the crud in the threads. They are caustic and not for human consumption but then, neither is penetrating oil. So no matter what you use, wire brush, Lime Away or similar chemical solution or god forbid penetrating oil, flushing with clean clear water.

Now if you are as old as I am, you may have heard of thread chasers. They are a tool with normally one row of what look like the cutters of a pipe die. We used them for cleaning pipe threads in steam powered torpedoes back in my Navy days.

I'd say I've used my tap and die set more often by far to clean up threads than to thread something. Well worth the cost and how quick it will solve a buggered up thread problem.

I'd say I've used my tap and die set more often by far to clean up threads than to thread something. Well worth the cost and how quick it will solve a buggered up thread problem.

Thanks again all. I bought a 3/4" round wire brush that I found in the plumbing section at the local Menard's. I will put something on the corroded threads to try to soften the calcium a bit. Let it sit over night and then try to brush it. If that doesn't work, I will have to buy a 3/4" tap.

fj12ryder wrote:

ktmrfs wrote:
I'd just by a 3/4" NPT tap and give it a run, just don't over do it. that should clean out the threads well.

This is the only way to do it right. I've tried all the others and none work very well. A tap is what you need to clean up the threads. Just don't overdo it.

Heck yeah. Got an elcheapo off ebay and keep around for that purpose. Why go thru all the round about home remedies?

Dusty R wrote:
A trick I've used to clean the internal pipe threads is to take a short piece of threaded pipe and cut 2 or 3 slots across the threads, with a hack saw or a cutoff wheel.

Yep, tried that one.

A trick I've used to clean the internal pipe threads is to take a short piece of threaded pipe and cut 2 or 3 slots across the threads, with a hack saw or a cutoff wheel.

ktmrfs wrote:
I'd just by a 3/4" NPT tap and give it a run, just don't over do it. that should clean out the threads well.

This is the only way to do it right. I've tried all the others and none work very well. A tap is what you need to clean up the threads. Just don't overdo it.

I'd just by a 3/4" NPT tap and give it a run, just don't over do it. that should clean out the threads well.