How to make a threaded connection of polypropylene pipes of different diameters

To organize a temporary system for watering beds or watering animals, you can use polypropylene pipes, connecting them not by soldering, but by threading. This will allow such lines to be disassembled and reassembled, for example, at the end and beginning of the season. This connection ensures complete tightness with low water pressure.

What you will need:

PP pipes 20 and 25 mm;
gas-burner;
metal fittings 1/2 inch with external and internal threads;
assembly knife.

The process of fusing threads on pipes

To connect, you need to melt the internal thread in the pipes 25 mm, and the external thread 20 mm. The result will be to twist them together. In addition, you can make short couplings from 25 mm pipe.

To make an external thread in a 20 mm pipe, you need to heat up any 1/2 inch fitting with a female thread.

Then she curls herself into it.

After this, you need to let the plastic cool completely, or simply pour water on top. The connection is then untwisted.

The internal thread on a 25 mm pipe is made in the same way, but with a fitting with an external thread. After production, you need to trim the sagging with a knife.

Since the fitting is heated, and not the pipe itself, the thread turns out to be very clear and durable, with even turns. When it is twisted, a tight connection occurs even without a fume tape. You only need to shorten the external thread if it is longer than the internal thread.