How to Check the Quality of Flaring Without Measuring

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Pressing is a fast and reliable method of joining pipe, but technical practice shows that the quality of the final joint depends not only on the precision of the machine, but also on the visual inspection of the process itself. Since we cannot use measuring tools to verify the depth of pressing for every installation, we must rely on proven visual indicators and tactile sensations, which provide immediate feedback on the correctness of the operation performed.

Visual inspection of the shape of the pressed ring

When pressing is done correctly, the pressing ring should take on a regular hexagonal shape without visible gaps between the arms, indicating even compression of the material around the entire circumference. If after removing the pressing head you notice that one or more arms are significantly longer or shorter than the others, it is a sign of an unsuitable size of the pressing head or incorrect pressure setting in the hydraulic system.

Technicians often use a mounting template for the PRESS - 100-150mm wall brackets to visually compare the shape with a reference model, although this tool is primarily used for fixing, its geometry can serve as a mental model for the expected result.

Verification of insertion depth before pressing

A quality pressed joint begins with the precise insertion of the pipe all the way to the end stop, where you should feel a firm resistance and see a small gap between the end of the pipe and the bottom of the fitting. If the pipe is inserted only partially, the pressing ring will not have sufficient support and during pressure testing, leakage will occur due to insufficient rectangular compression.

For operational applications, such as the PRESS - external thread - 1/2"Mx16 or 3/4"Mx20, it is critical that the pipe reaches the bottom, because otherwise the O-ring will not close properly and a microscopic space for leaking water will be created.

Tactile check of temperature and resistance

One of the most reliable methods of checking without measurement is touching the pressed area immediately after the process is completed, where a properly made joint should be equally warm as the surrounding pipe and have a firm, "dull" sound when tapped with a hammer. If the joint is colder or, on the contrary, hot due to friction during pressing, or if it produces a hollow sound when tapped, it means that the pressing ring is not sufficiently tightened or that the pipe has shifted.

The joint must be smooth and without sharp edges on the edges of the ring.
When tapped, it should sound solid, not like empty sheet metal.
It should not be visibly deformed beyond the regular hexagon.
The O-ring should be completely hidden and not protrude from the side.

For external thread adapters, for example type 3/4"Mx26, this check is important because an incorrectly pressed bottom can cause the threaded end to be difficult to turn or not to fit properly when connecting the radiator.

Identification of faulty pressing according to surface

The material of the pressing ring should show fine, regular grooves from the pressing dies after the process, which should cover the entire circumference without interruption or deepening in one place. If you notice shiny spots indicating friction without compression, or on the contrary, dark areas where over-pressing has damaged the metal structure, the joint is unsatisfactory and must be removed.

It is important to remember that brass fittings tend to vary slightly in color after pressing depending on the pressure, while steel ones may turn a darker color, which is normal as long as the material is not torn.

Risks associated with reusing rings

Pressing rings are intended for single use and reusing them on an old fitting is one of the most common causes of leaks that appear weeks after installation. Although the ring may appear undamaged at first glance, its metal structure has already been permanently deformed and has lost the elasticity necessary to create a sealing effect against water and pressure.

Our practical experience shows that technicians try to save by using a new ring on an old fitting, which is however a critical mistake. Always use new O-rings and pressing rings, especially for smaller sizes such as 16 mm, where the margin for error is minimal. If you suspect reuse, always disassemble the joint and replace it with new components.

Importance of the correct choice of pressing head

Choosing the wrong pressing head for a given pipe diameter is the main cause of visually incorrect joints that appear to be in order, but are in fact dangerous. The head must exactly match the pipe diameter and type of fitting, otherwise uneven compression occurs, which is manifested either as under-pressing (too small arms) or over-pressing (material tearing).

For various types of fittings, such as PRESS inserts 16, 20 and 26 mm, there are specific heads that differ in depth and shape. Using universal heads without verification is risky, so always check the compatibility of the crimping tool with the specific type of fitting you are using, for example with transitions with an external thread 1/2"Mx16.

Gap analysis in the crimping area

In a correct process, no visible gap should form between the edge of the crimp ring and the body of the fitting, which would indicate incorrect depth of installation or damage to the sealing profile.

Frequently asked questions

Can I use a crimp ring multiple times?

No, crimp rings are designed for single use and reinstallation leads to loss of sealing ability and a high risk of water leakage.

What should I do if the crimped joint is asymmetrical?

If the joint has visibly uneven arms or is distorted, the joint is unsatisfactory and you must immediately cut it off and replace it with a new one, as it cannot withstand pressure.

How can I distinguish between a good and a bad crimp without measuring?

A good joint has a regular hexagon, even grooves on the surface, a firm sound when tapped, and the pipe is inserted all the way to the stop without a gap.

To conclude, it can be said that although modern crimping systems offer a high level of reliability, the final quality check remains in the hands of the technicians and their ability to identify visual and tactile signs of correct crimping is key to the safety of the entire heating system. Regular monitoring of the shape, surface and depth of installation will allow you to prevent costly repairs and leaks even before the system is put into operation.

Do you have a question about this topic?

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