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Adequate Flair?

bshawco

Active Member
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Adequate Flare?

I'm trying to flare 3/8" fuel lines using the Imperial 2-piece flaring tool & a couple drops of oil. I've practice at least 20 flares, and I think I must be doing something wrong.

I've watched several videos, followed the VAF threads as well as the instructions that come with the tool and section 5 of the KAI. I've tried cranking on the tool both lightly and as hard as I can. I've tried starting with the end of the tubing flush with the top of tool and with it slightly above it.

Attached below are photos of my best flare next to a T.S. Flightlines flare (on the right), and I'm obviously not getting as much of a "neck" on my flares. The last photo is my flare with a sleeve.

My questions are whether my flares are likely to be adequate or not. If not, any tips would be appreciated. I'm also wondering if I just need to break down and buy the Rolo-Flare tool which is the alternative flaring tool carried by Aircraft Spruce.
 

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Confirm that the Imperial tool is a 37 degree flare type.
Other than setting the tube a bit deeper in the tool so the 'neck' ends up same outside diameter as the blue sleeve, should be good.
 
It looks to me like that tube wasn't inserted far enough in the tool. Those circular marks on the exterior of the cone look like it was probably smooshed into the die part of the flaring bar.

You mentioned cranking it down, but typically you don't want to bottom out the cone point in the socket. Certainly if you crank it down like I think you mean, you're weakening that flare where it has a good chance of cracking radially in the transitions back into the unflared portion of the tube.

From the time the cone makes contact with the tube, it should take about 1/2 dozen cranks on the handle to create a proper flare and that should happen before the flare cone starts to crush the flare into the chamfer on the flaring bar. If it doesn't, then you likely didn't have it inserted far enough.
 
The directions for the tool suggest that the tube should stick out of the bar to approximately the same thickness as the foot of the flaring tool (the part with the crank in it. That foot is something more than 1/4”. In other words, the tube sticks “way out” of the bar and the flaring action never gets close to the bar. With my tool I have found that 3/8 tubing is best flared with seven half turns of the handle from the first contact.
 
Typically, the flare should be about 1/2 the width of the flared part of the sleeve. Yep, takes some practice. Extend the tube out from the flare die about .060 and try again. Should be about perfect.

Tom
 
Thanks for all the tips and suggestions. The 37 deg flair tool I have is the Imperial 437-FB Hi-Duty model.

After more practice today, the best looking flares I've gotten were when I had about 1/4" of tubing above the yoke. The instructions for this model say the top of the tubing should be flush with the top of the yoke. One video suggests the top of the tube be about 1/64" above the top of the yoke. I'm hoping more practice will do the trick.
 
Didn't see any mention above , but I have problems similar to some of your pictures if the cut off end to be flared is not reamed out sufficient. Or sometime cut with a set of cutters with too much pressure on the roller at the final rounds of the cut. Some of the pictures looks as if the cut end may have rolled into the flare formation which will make a substandard flare connection and poor seal. Maybe not as much of a flare formation operation as a cut and prep operation.
 
Sorry.....couldn't resist

v/r,dr <G>
 

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your, you're ; dear, deer; bear,bare; whole,hole; there's a bunch of them, just add flare and flair to you're list !!!! But we all knew what the subject was about.
 
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D'oh! I didn't even THINK of "flair" vs. "flare" but I managed to use both in the original post. Guess I'm so freaked out by flaring that my proofreading has flared out.
 
Flare

I was out bush one day fixing a cool room, the copper flare 1/2 in cracked and my flaring tool nowhere to be found😢. I cut the tube fitted the nut and heated the end with Map torch,rounding out a reasonable flare with a 10 inch star screwdriver. Whilst still hot tightened the nut, never leaked ever since! Aluminium tubing is soft, if you don’t flare too wide and cause the pipe to crack the nut will close up any slight angle difference👍
 
All it takes is practice, with what ever flare tool you use. RFT37, RoloFlair, etc. All are slightly different. Advice----cut some sections of straight tube, square the ends with a file and through some trial and error, figure out how much the extend the tube past the flare bar to get the right amount of flare, once the sleeve is installed.
For most of you, you'll be using 3003O-.375-.035 tubeing for fuel. So I'd start with extending the tube about .060 from the flare bar. Flare it per the tool instructions, then slide the sleeve up and see how it all matches. Shouls be about 1/2 the width of the sleeve. If you get it small, just reflare it slightly larger. If its too big, sometimes you can reduce the OD with a belt sander. The trick is once you fine the sweet spot, make a measuring tool to use with the bar to get the tube to the right height prior to flaring. Something like a rivet height gauge is the idea.

Now if you flare a different OD/ID tube of different material ( Like 304 stainless, .375OD/.065 wall) obviously more testing and practice will be needed.
Its part of the 'education and recreation' section of the build process. The 'education' turns into frustration for quite a while, until you get comfortable, then it becomes 'recreation'--

Tom
 

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Thanks for the detailed suggestions and encouragement, Tom. I may go through my entire coil of factory fuel line practicing, but so be it.
 
Brad---you might use some, but its really not that much. You are just flaring a couple of inches so its not alot. Once you fine the sweet spot on a particular size of tube, make a little guage and hang it on the flare tool so you'll always have it.

Tom
 
'Aviation Technician Integrated Training Program EA-ITP-GB","General section textbook. I got it from a fomer Marine Helicopter mechanic after he retired.

The old manual is here----start on page 192 for rigid tubes--

Tom
 

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Rolo-Flare

For what it's worth to any other flaring newbies, I finally bought the Rolo-Flare tool and found it much easier to achieve good-looking flares right away.
 
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