How to Make Bubble Flare With a Double Flare Tool

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Flares are the main reason behind your vehicle stopping after pushing the brake pedal. Flares help the brake system to produce compression that appears in the master cylinder to begin the brake system. It makes the inside systems of your vehicle airtight; thus, the vehicle can stop at the place.

But did you ever wonder what can happen if your car’s flares are bad? As the major part of the brake is a flare, you can’t let it be bad. You can make a double flare or bubble flare. You need to make a bubble flare first to make a double flare, but can you make a bubble flare with a double flare?

How to Make Bubble Flare With a Double Flare Tool

What is a Double Flare Tool?

A double is created by rolling or folding the end of the tube inside itself, and this is the moment when the double layer is flared. Double flare has ahead with the groove in it where a flaring kit with different size inserts. And this groove is located at the end of the tubing. That’s how when you apply pressure, it folds down the edge to the inside, and it helps to make the double layer. 

What is Bubble Flare?

When the end of the tubing somehow looks like a button and the flare’s backside angle is about 90 degrees, then you have a bubble flare. But if the backside angle is about 45 degrees and the brake line looks similar to a tiny funnel that is going into the tubing’s ID, then they are SAE or double flare. 

If you are thinking about using the double flare in a place bubble flare, then you can’t do it. The port and line’s shape of these two flares are completely different, and they don’t even make an effort to seal. If you have enough patients and the necessary tools, then you can re-use the leftover nuts by drilling the line. 

There are a few types of flares that are sometimes called bubble flares. For example, Late Spider utilizes a brake line flare style that requires the application to have a high torque over a small nut to seal. The nut’s shoulder put pressure on the widest part of the flare. While this style indicates the bubble flare as its shape is round. 

What is The Common Difference Between a Double Flare & a Bubble Flare?

The difference between these two mentioned flares is somehow fine-drawn. But if you have good knowledge and are familiar with brake lines, then the difference between a double flare and bubble flare is mostly visible to understand. 

The double flare has a great funnel shape, but the surface of this flare resembles a line placed inward towards itself. The appearance of the flare gives it a circle feel with a good thickness. 

Like other flares, bubble flare only resembles the difference at the top of it. The top of the flare looks like a screw, and the circle end has a smaller diameter. You can also describe the bubble flare as a swollen hollow-topped flare. 

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Is a Double Flare The Same as a Bubble Flare?

No, a double flare is not the same as a bubble flare; they both consist of different flare styles. But you need to make a bubble flare first to create a double flare. In most vehicles, these two types of brake line flare are widely used. A double flare is almost similar to all the standard flares, like single flares. But double flares are lit more durable than single flares. 

The majority of vehicle manufacturers from around the world have decided to adopt double flared for brake lines. But it’s not like bubble flares are not being used anymore; you will find this flare mostly in European vehicles. 

Techniques for Building The Flares

You may require a few different tools while building these two types of flare. The process of making these flares are not that critical, and you can follow our steps below to make a double flare and bubble flare: 

The Steps for Making The Double Flare are:

  • First, you need to measure the line to cut the line. Make sure the cutting tool is maintaining alignment and the materials of the flare are tightened. 
  • Now clean the cuts; please don’t overlook this step. You will require a good cutter and try to avoid uneven edges.
  • Now the third step of building a double flare is setting up the tools for brake flaring. The flare contains two parts that move, and to keep the tool steady, you will need to provide adequate pressure. 
  • The next step is to apply the hardware to the brake line. You should prevent unnecessary sliding of the hardware before flaring. 
  • Now clamp the brake line with the tool and must maintain a proper alignment.
  • In the next step, you need to lubricate the line, and it will complete the process of using brakes. You must avoid silicone-based lubricants to perform this part.
  • The seventh step is to flaring the lines by using a fitting wrench that helps to tighten the tool for flaring. 
  • The eighth and the last step is double flaring. This step is basically the repetition of the process. But you should avoid inserting while doing this. 

The Steps for Making The Bubble Flare are:

To make a bubble flare, you will need a good tubing cutter that has a sharp cutting edge. The cutter also should not have any chip or deformity as this one is the most vital thing to make tubing flares. To make the bubble flare, you can follow the below steps: 

  • If you use a cutter with a cut-off wheel, it will create a weak point that can make room for leakage. In fact, a leak may start as soon as you cut the line. So to prevent this leak, you need to attempt a clean and clear cut on the tube. 
  • The next step is setting the clamp with the tuning inside the flare once you are done cutting the tubing perfectly. It would be better if you choose the die with bubble flare stamps because they are extremely effective in making bubble flare.
  • The third step is to set the brake line on the lower half of the die as it can provide surety that the bubble flare’s end of the die is flat and square. That’s how you can mount the die from the top half of the tubing. Now you need to turn the clampdown, then install the pin in the clamp. 
  • Once you are done, you need to do the third step, and you need to tighten the clamp To make sure that the die halves are clamping together tightly. 
  • The last step is lubricating the brake line after the line is clamped properly. You need to set the lever somewhere around 90 degrees.

And that’s it! Your double flare and bubble flare are ready, and if you have followed the above steps properly, then we are pretty sure you won’t have any issues with the flare. Both of the flares are ready to be used in your vehicle’s brake systems. 

Can You Use a Double Flare tool to Make a Bubble Flare?

Yes, it is possible to make a bubble flare by using all double flare tools. It can happen because a great number of double flare kits come with all-in-one features that have the ability to make any kind of flares that are available. You can also make a single flare beside the bubble flare with a double flare kit. 

Generally, to make a double flare, first, you need to create the bubble flare. So it means that you can make a bubble flare with double flare tools. On top of that, you will have an extra benefit by having an all-in-one flare kit. 

What Are The Brake Lines For Bubble Flare vs. Double Flare?

The depression of the brake creates compression when you apply pressure on the brake pedal. And this compression appears in the master cylinder that creates hydraulic pressure. It helps the fluid to spread all over the car, and gradually the brake systems start working to stop the car. 

The main criteria of the brake system are that there can’t be any air inside the car system which means the car’s inside has to be airtight. And this is a place or scenario where the flare is needed to be used. As mentioned above, the two most widely used flare types are double flare and bubble flair brake lines. 

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The Double Flare Brake Line

Two different types of flare are used in the automotive braking system. And double flare is the most common flare between them. Double flares are surely famous and well-known flares, but in European countries, most of the vehicles have bubble flares.

The shirt acronym of the double flare is SAE, and they are inverted style flares. The acronym is more popular than the real name of double flare. The double flare contains the capability to maintain different dissimilarities of production.

The system of the double flare put the end line of the braking system inside it two times. When you do that, the double flare needs the lip of the single flare with the intention of staying folded on the system. The system of a single flare is almost the same as a double flare. 

However, single flares are not durable and sturdier at all, like double flares. Thus, double flare can create more pressure inside the braking system. A double flare is a good example of bearing high pressure, while a single flare can’t handle it.

The Bubble Flare Brake Line

Bubble flare is a type of braking system that is vastly used in European countries while making a car and other vehicles. Especially when European Union imports cars and other vehicles to the other countries, they use this flare type mostly. Besides the EU, many Asian countries and America utilize this flare brake line in their cars, but they are limited. Bubble flares are also familiar to people as DIN/ISO.

If anyone is interested in creating a double flare, then they have to develop a bubble flare first. The shape and outlook of the bubble flare is someone like a screw. You will find a flare at the bottom of the bubble flare at 90 degrees. 

You can also make a bubble flare with a double flare, but you will require a double flare’s all-in-one kit. However, bubble flares are less capable of handling higher pressure while double flares can handle it. This is what makes the double flare more preferable than the bubble flare.

Temperatures of Each Brake Flare Lines

Almost all the brake flare lines consist of two different temperatures, which are 37 degrees and 45 degrees. The commonly used and polar temperature of the flare is 45 degrees. And the double flare is the one that has a temperature of 45 degrees. While the bubble flare has a temperature of 37 degrees. 

Double flares are sometimes called by 45 degrees flare instead of their real name. The US Army and the Navy generally use a bubble flare brake system in their vehicles. The JIC also works with a temperature of 37 degrees as the base of the fitting. 


Using a double flare kit is more beneficial than using other flare kits. You can make a bubble flare and single flare with the help of a double flare tool that is an all-in-one kit. In short, you can make any kind of flare if you choose to buy an all-in-one double flare kit.

From the above discussion, you get to what the meaning of double flare and bubble flare is and how you can make them. We tried to provide you all the necessary information that you require to learn whether you can make a bubble flare with a double flare or not.

Avatar for Jack R. Stephen

I am Jack R. Stephen from Dallas, TX, USA and Co-Founder of Handy Tool Tips. I am a tool expert with years of practical experience. Besides my professional work, I love writing to help others with knowing handy tools thoroughly. For recreational & enjoyment purposes, I love going to hike with my best friend, Cameron. He was mentioned in several News Portals for his outstanding skills and professionalism for making great stuff with his tools. If you would like to chat with me please feel free to reach out via facebook or twitter or email.

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