Plumbing in the Home/plug line


I am trying to plug the end of a copper tubing line. The flare nut initially tightens on the first few threads of the plug then spins freely and will not tighten any more. What can be done to resolve this problem and plug the line? Are there any alternative solutions to prevent water flow from the end of the line?
Thank you

Hello AG,
The most effective way is to sweat a copper fitting cap on the end. The end needs to be cut clean and square and be clean. There must be no water running at the time.

Alternately, look into a "Sharkbite" fitting, possibly even a valve.
Sharkbite fittings are designed to work by pushing them in place and usually require no tools. They are self sealing and removable.

Good Luck,

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


Retired, Licensed General Contractor with Plumbing license. Active Home Inspector, Litigation Consultant and Infrared Thermographer, Online Marketing specialist.

Publications "Rain Maker" as "Inspector Dana", about making money online.

30+ years in the building trades, Licensed General Contractor (Retired), Certified Infrared Thermographer Internet Entrepreneur, Amazon & eBay Merchant (deals-by-dana)

Awards and Honors
Listed FHA Fee Inspector, FHA 203(k)Consultant, HUD Mobile Home Inspector

Past/Present Clients
Home buyers, sellers and owners, Investors, Commercial roofing companies (infrared roof scans for moisture intrusion, Litigation Consulting for "Slumlord" laws in SoCal

©2016 All rights reserved.