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They are produced in compliance with the Japanese Industrial Standard, JIS H3300. This standard is used to represent copper alloy and copper seamless tubes and pipes.


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1. What is Copper Coils?

Copper coil or Copper pancake coil is a product that is commonly used in HVAC industries (Heating, ventilation, and air-conditioning). The purposes of the copper coil are to assist in equipment connecting, maintaining, and circulation, and fuel conveying systems of natural gas and liquefied. It is one of the most preferably used equipment all over the industry due to its economical material prices, which it’s also durable and reliable as well when it comes to having a good electrical conductivity amongst the other metals.

2. What is Copper Coil used for?

Copper coils are commonly used to join capillary fittings by going through a soldering or brazing process. Soldering methods are usually needed when it comes to the usage in water lines plumbing and for sanitary drainage. While greater joint strength is needed for when the service temperature is over 350°F (176°C), brazed joints of the copper coil with capillary fittings will be preferred. Additionally, during the installation of air-conditioning and refrigeration sector.

3. What are Copper Coil specification?

copper coil

Copper coils are lightweight, high corrosion-resistant, suitable for heat exchangers, and it also minimizes the need for joints. Our copper coils are manufactured in accordance with the requirements of specifications under JIS H3300. 


JIS H3300 standard made it specific that expanded copper and copper alloy seamless pipes and tubes, having a round section.


Hard temper is referred to as drawn temper, whereas soft temper is referred to as annealed temper. Thus, tempering is the key to the hardness and strength of the coil, which is drawn and annealed during the process. The copper coil is a soft temper pancake coil, which can be bent easily with the pressure of hand grab force. Nevertheless, it is recommended to use the right and suitable bending tools during the bending process. The ease of bending makes copper coils economical as it does not require a lot of joints.

Copper Coil

4. What are Copper Coil attributes?

Under the JIS H3300 category, 245 N/mm² - 324 N/mm² are the estimated amount of tensile strength for the copper coil. For AF Hydro’s copper coils, it contains a minimum 99.90% of copper (CU) and a range of phosphorus in 0.015% - 0.040%. The chemical combination in this copper material is known to be phosphorus deoxidized copper. The result of deoxidized copper with phosphorus chemicals is to reduce the cuprous oxide and remove porosity by acting as oxygen removal during the manufacturing process.

5. What is the difference between soft and hard coppers?

The strength and hardness are determined by the temper of the copper coil. In the piping industry, temper is differentiated into two categories which are: the annealed tempered, known to be a soft tube, and the drawn tempered, known as the hard tube.


In our product line, we offer only one category type which is annealed tempered, the soft-typed copper coils. During the installation process, compression and flare type fittings are commonly being used to connect with soft tempered copper coils. Capillary fittings are often used by users to solder braze or weld copper coils together.

Hard coils are commonly referred to as pipes, it is well known for their uses in water lines which are totally opposites of copper coils. The hardening process that the stiff copper goes through makes it extremely difficult to bend unless the heating procedure is repeated to soften it.

6. What is the difference between Copper Coils and Tubes?

Copper coils and tubes are terms that are often used interchangeably. When it comes to measurement and dimensions, however, the two terms have distinct connotations for marine engineers. The table below are some of the following differences between copper coils and tubes:

7. The outer diameter and coil thickness specifications

Inches and MM are used in measuring the copper coil outer diameter (OD). For Inches OD, it is available in the size of 1/4” OD to 7/8” OD. While for MM OD, the available size for the outer diameter is from 6MM to 15MM. The table below illustrates the OD tolerance under the JIS H3300 category.

Copper coil thickness is available in two different measurements which are MM and Standard Gauges. For MM thickness, it is available in 0.9MM, 1.2MM, and 1.5MM. Meanwhile, for the Standard Gauges thickness, it is available in SWG or BWG. The table below provides the thickness measurement for Standard Gauges.

Install: Tubes



Capillary fittings come with a socket type end, with the function to eliminate the tolerance gap between the copper coil and the connecting fittings. Thus, both the copper coil and the capillary fittings can produce a narrow even gap when assembled as soon as the copper coil and capillary fittings have been cleaned and fluxed. As a result, when the solder is heated until it melts, the force of adhesion and cohesion cause the molten solder to stick together.


Measure and cut the copper coil to the desired length, being careful as a note to not cut it too short or too long to ensure a proper connection.

Copper Coils


Use tools like sandpaper or steel wool to clean the coil and capillary fittings. Once cleaned, an adequate flux will be applied, which results in a thin layer on the mating surfaces. This process is done thoroughly to keep dust and debris out of the capillary gap. Which moves on to the next step, to heat up the joint after copper coil and capillary fittings have been fluxed.

copper coil


Heat the joint. Please be cautious and avoid melting excessive solder into the capillary gap when soldering. Heat the joint. The solder is brought to the area of the capillary gap to be heated. Keep heating the solder until it melts. Ensure that the capillary gap should be filled with enough solder all around the coil.

Copper Coils


Here comes the cooling process. The next step will be the cooling process, in which the heated solder will be allowed to cool down before solidifying and closing the capillary gap completely.

Copper Coils


Finally, use a cloth to wipe and remove any excess flux on the outer surface of the tubes.

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