How to properly and securely wind flax onto plumbing connections

Despite the availability of modern materials for sealing plumbing threaded connections, flax remains relevant due to its reliability, resistance to high temperatures, the possibility of adjustment and a long service life. Even with all the advantages, not everyone is ready to use tow, since working with it takes longer and is more difficult, and besides, it is possible to overdo it with its quantity, which causes fittings, shut-off valves or other elements to burst. If you adhere to certain rules, then all this can be avoided and only positive properties can be achieved from the compound.

What is needed to seal joints with flax

Unlike anaerobic gels, when working with tow, you cannot tighten the connection by hand. In this regard, before starting work you need to prepare:

• adjustable wrenches;
  
• gas keys;
  
• flax fibers;
  
• plumbing paste for Unipak type sealing.

How to use flax correctly

The purpose of using flax is to tightly seal the space between the external and internal threads of the two elements being connected. If you wind it right away without preparation, then it will be difficult to tighten the fittings in the future. You must first run them dry so that the threads get used to it. If you have to work with different materials, for example, a brass barrel and an American cast iron for a circulation pump, then it is simply impossible to tighten the connection manually. In this case, it is convenient to fix the barrel in a vice, and if you don’t have one, then a gas wrench will do. The connection must be driven to the end several times so that it can be screwed and twisted by hand.

After grinding the thread, you need to take a bunch of flax. Ideally, the tow should be clean without straw. Its quantity is taken based on the thread depth. The higher the diameter of the elements being connected, the more tow will be required.

The bundle should be combed out by hand and the fibers leveled, then begin to wind from the middle of the nipple.


This should be done in such a way that the flax is folded in half with a small tail. Its loop is thrown onto the thread from itself. The tail is wound counterclockwise.


Having tucked the tail under the main flax whip, you need to start winding the remaining long bunch of tow clockwise. It is laid with a wide tape so that each turn lies halfway on the old loop and partially extends onto the clean thread.



Gradually blocking the thread, you need to move to the edge of the fitting. If there is a small tail left, you can start winding it back to the middle. The flax needs to be smoothed by turning the joint between pinched fingers so that it tightens and does not unwind.

Now, ideally, lubricate the surface of the flax with a specialized plumbing paste, which will prevent it from rotting and increase its service life many times over. It will act as a lubricant and make screwing easier. You can do without it, but only in sections of the pipeline that allow you to easily carry out repairs. For clarity, I do not use it in this example.


After preparing the element with external thread, you need to screw on the American thread, tap, plug, or whatever is needed. If the tow is wound correctly, then after the connection is completed, the flax practically does not protrude. Rare protruding fibers are convenient to cut off with a blade, and even easier to burn with a lighter.
Unscrew the connection.

As you can see, the flax clearly sealed all the grooves of the thread.
When using tow, if it turns out that the thread has been overtightened and this interferes with further installation, then it can be released or tightened. This connection allows up to 45 degrees of rotation in both directions. Of course, when tightening, you cannot overdo it so that the connected elements do not burst.

Watch the video

Be sure to watch the visual and detailed video.