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Hints for double flaring a new fuel line
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56D500boy
Posted 2022-02-14 3:40 PM (#619392)
Subject: Hints for double flaring a new fuel line



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As part of a swap from generator to alternator, I have to create a new fuel line that avoids a conflict with the alternator. To that end, I bought what I think (thought) was a decent kit (see below). Before I tackle cutting and flaring a 5/16" x 30" line (down to about 25"), I am playing with (learning on) a 20" piece.

So far I have watched a few YouTube double flaring videos and tried it once on the practice line (after cutting off the supplied double-flared end).

I failed. (Didn't get a full double flare)

But I wonder if the steel tubing that I bought is too hard to work with this kit and that I should be looking for bulk softer tubing (at least I have the fittings already). (???)

This is the tubing I bought:



This is the flaring kit that I bought (and have tried). I will try (practice on the 20" line) again today:



Edited by 56D500boy 2022-02-14 3:42 PM




(OTCDoubleFlaringKit.jpg)



(OTCDoubleFlaringKit_Inside.jpg)



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Attachments OTCDoubleFlaringKit.jpg (120KB - 124 downloads)
Attachments OTCDoubleFlaringKit_Inside.jpg (210KB - 131 downloads)
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wizard
Posted 2022-02-14 3:56 PM (#619393 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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Normally, with those kits, the flaring bar cannot hold the tube. Try putting the bar in a wise and ensure that the tube cannot slip. The cut must be straight and file away any uneven parts, in and outside.
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ronbo97
Posted 2022-02-14 5:18 PM (#619396 - in reply to #619393)
Subject: Re: Hints for double flaring a new fuel line


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I would recommend getting a quality brand, rather than this Chinese junk. Lisle, K-D are a couple brands that come to mind. I've used this type of kit to get good quality double flares on brake and fuel lines. It's important that you use a special brake/fuel line cutting tool. It looks like this:

 

Also, you'll be using a lot of force to accomplish the second half of the double flare. Get out the heavy duty vice grips.

Ron





(tool.JPG)



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Attachments tool.JPG (47KB - 71 downloads)
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60 dart
Posted 2022-02-14 6:14 PM (#619397 - in reply to #619393)
Subject: Re: Hints for double flaring a new fuel line



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wizard - 2022-02-14 3:56 PM

Normally, with those kits, the flaring bar cannot hold the tube. Try putting the bar in a wise and ensure that the tube cannot slip. The cut must be straight and file away any uneven parts, in and outside.


exactly!
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60 dart
Posted 2022-02-14 6:19 PM (#619398 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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you can buy one of those mini tubing cutters just about anywhere but quality is a key issue as with
some , the cutting wheel doesn't track properly or tightening threads wear out real quick---------------------later
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56D500boy
Posted 2022-02-14 7:40 PM (#619399 - in reply to #619398)
Subject: Re: Hints for double flaring a new fuel line



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Thanks for all the hints guys.

The first one that I acted on was to dig out my mini tubing cutter (like the orange one posted above). I used it to cut off about an inch of my trial tube. Then I used a fairly fine metal file to further square off the tubing and chamfer the outside. Then I used a box cutter to clean out the inside edge of the freshly cut tubing.

Then I placed the tube in the tubing flaring bar at the height suggested in the instructions and tightened the two thumb screws with pliers, i.e. very tight. I did not put the flaring bar in the vice to squeeze the tubing. Maybe next time.

Once the tubing was firmly clamped in, I used the bubble button to complete the first phase of the flare, the bubble.

Then I removed the bubble button and used the 45 deg flare point and torqued things down until I could go no further. That created the flare.

Guess what? I think that I got it, second go. See below. Fits nicely in a 45 deg female brass fitting that I am going to install in the discharge port of the fuel pump.

Thanks again. I hate to still be a noob and ask questions/ask for hints, but that is better than just screwing things up until I eventually get it right. (This applies to almost everything that I am doing on my 56 Dodge).

PS: I hear you on the quality of the flaring kit. This will do for the few things that I have planned but if there was more, something much better would be required.





Edited by 56D500boy 2022-02-14 7:45 PM




(DoubleFlareTrial_IstOnLeft_2ndOnRight_1B.jpg)



(DoubleFlareTrial_IstOnLeft_2ndOnRight_2.jpg)



(DoubleFlareTrial_2ndTrial_InBrassFitting.jpg)



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Attachments DoubleFlareTrial_IstOnLeft_2ndOnRight_1B.jpg (105KB - 70 downloads)
Attachments DoubleFlareTrial_IstOnLeft_2ndOnRight_2.jpg (97KB - 73 downloads)
Attachments DoubleFlareTrial_2ndTrial_InBrassFitting.jpg (73KB - 71 downloads)
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1960fury
Posted 2022-02-14 8:51 PM (#619400 - in reply to #619399)
Subject: Re: Hints for double flaring a new fuel line



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56D500boy - 2022-02-14 7:40 PM



Guess what? I think that I got it, second go. See below.



I'm sorry, not really. Look at how distorted and uneven the 2nd flare is. One edge is longer than the other. I got to admit, I learned how to flare in mechanic school and it kinda worked.
Later, with my own cheap tool, I always struggled. I even got a tool once (chinese), from Eastwood, that had the channels cast a couple degrees off (not 90°)!
Finally bought a quality tool with much better results, but for some reason some flares still went bad. Very frustrating, and flaring was always kinda nightmarish for me. Especially if you had the properly bent tube cut to length for the final flare...

Guess what, to my embarassment, I finally learned how to flare on Youtube from an American Youtuber! I learned, that the tube cutter not always cuts the tube square and it is very importand, that you clamp the tube into the tool, before you flare it, so the pipe end is almost flush with the OTHER side (not the 45° camfered side you use for flaring), slightly protruding and to file the tube 100% square. Ever since I never goofed again and it was a big relief for me!

Edited by 1960fury 2022-02-14 8:56 PM
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local2Ed
Posted 2022-02-14 9:19 PM (#619402 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line


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Get a Eastwood or similar brake line de-burring tool and use the drop of brake fluid on the anvil when you make the bubble part.

Having a slightly crooked outside chamfer will make the final flare crooked.

Edited by local2Ed 2022-02-14 9:21 PM
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mikes2nd
Posted 2022-02-14 9:51 PM (#619404 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line


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I like the Titan 51535 3/16-Inch Double Flaring Tool bette than the super cheap chinese tool....

they are quality, i used that one.
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56D500boy
Posted 2022-02-15 2:53 AM (#619406 - in reply to #619404)
Subject: Re: Hints for double flaring a new fuel line



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mikes2nd - 2022-02-14 6:51 PM
I like the Titan 51535 3/16-Inch Double Flaring Tool bettet than the super cheap chinese tool....
they are quality, i used that one.


Sure. I like the Titan-Tools-51535-Double-Flaring tool too. One problem. I am dealing with 5/16" fuel line tubing, not 3/16" brake line tubing.

Del S offered to lend my his Titan 51535 when I get to making the brake lines from the new dual master.

But until then, I need to make one good 5/16" double flare for my fuel line.

The Titan tool (I can get it cheaper locally):

https://www.amazon.com/Titan-Tools-51535-Double-Flaring/dp/B06XPRVCP...

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wizard
Posted 2022-02-15 12:05 PM (#619421 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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Check the flare with a magifying glass and look for "hair cracks" if you cannot find anything its ok.
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1960fury
Posted 2022-02-15 7:45 PM (#619435 - in reply to #619421)
Subject: Re: Hints for double flaring a new fuel line



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wizard - 2022-02-15 12:05 PM

Check the flare with a magifying glass and look for "hair cracks" if you cannot find anything its ok.


No. It shouldn't be taken too lightly. Brake or fuel line. The flare should be even and the actual sealing edge (contact area) not too wide, that seals better and that also means you still have some spring action that "locks" the connection (like a lock washer) and adds some safety.

Most flares by hobbyists are overstretched. Both flares shown here shouldn't be used in any fuel system. Also the cheap chinese tools add some predetermined breaking points where cracking is most likely anyway.
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56D500boy
Posted 2022-02-15 9:09 PM (#619437 - in reply to #619435)
Subject: Re: Hints for double flaring a new fuel line



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Sid: Neither of those practice flares are going to be used. I will use your suggestion about filling the cut tubing flat using the flaring bar when I make the one necessary double flare tomorrow (or the next day).

I will still be an amateur and I will still be using the Chinese flaring kit when I do that.

Are you suggesting that I am doomed to failure and will soon be going up in giant fuel fire?

What course of action are you suggesting?



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1960fury
Posted 2022-02-15 9:22 PM (#619438 - in reply to #619437)
Subject: Re: Hints for double flaring a new fuel line



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56D500boy - 2022-02-15 9:09 PM


Are you suggesting that I am doomed to failure and will soon be going up in giant fuel fire?



Very likely not, but catastrophic failures are usually a chain reaction of several "odds" that happen to happen at the same time. It is just my way of thinking, that wants to rule out the odds that can be prevented. There are others, that can't.
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ronbo97
Posted 2022-02-15 10:14 PM (#619441 - in reply to #619438)
Subject: Re: Hints for double flaring a new fuel line


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You won't be doomed to failure, but you'll be doomed to a leaking fuel line.

If you don't want to put out the money on a quality flaring tool, then borrow one. Many auto parts stores around here loan out tools for free. They will likely have a good quality flaring tool.

"Do it once, and do it right"

Ron

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1960fury
Posted 2022-02-16 10:30 AM (#619450 - in reply to #619441)
Subject: Re: Hints for double flaring a new fuel line



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ronbo97 - 2022-02-15 10:14 PM

You won't be doomed to failure, but you'll be doomed to a leaking fuel line.



Next time, at night in the dark, open the hood and watch your engine running. My guess is, you see lots of sparks everywhere a stock spark plug wire touches another or ground. Leaking fuel line=possibe fire.
This is what I meant. A spark can occur anytime due to a crack in the insulation or aging rubber, that still looks ok, especially with dirty or improperly gapped spark plugs. I even saw ignition sparks jump to an old heater hose!
Leaking steel fuel lines can be prevented. I wouldn't try to save money with cheap chinese tools when it comes to safety.
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local2Ed
Posted 2022-02-16 1:51 PM (#619461 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line


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https://www.dormanproducts.com/p-36599-800-142.aspx

If all else fails, buy a line longer than you need and two-piece it, keeping the factory flares.
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57chizler
Posted 2022-02-16 2:36 PM (#619465 - in reply to #619441)
Subject: Re: Hints for double flaring a new fuel line



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ronbo97 - 2022-02-15 7:14 PM

If you don't want to put out the money on a quality flaring tool, then borrow one. Many auto parts stores around here loan out tools for free. They will likely have a good quality flaring tool.


I agree and, as added insurance, I always lap the finished flare. Lapping gives you visual assurance that the surface of the flare is even.

https://koultools.com/product/flare-lapping-tool/
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PolyJ
Posted 2022-02-20 2:57 AM (#619588 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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Hey, 56D500boy, I have a few tips and comments to hopefully help you along.

First, you can buy 25' rolls of quality line from Jegs at good prices, which is what I do to make up my fuel, brake, and vacuum lines. In my experience, quality zinc-plated tubing flares a lot nicer than the store-bought prefabbed black/green/brown tubing. Plus, you'll have plenty of line to play with.

I also second what Wizard and Ronbo97 said about quality tools. I have both a KD kit and an older USA-made kit similar in design to your kit. Interesting, the best flares I get are using the type of clamp you have with the KD compressor that has a vise on the side to really squeeze/capture the tubing in the clamp. I put the extended tang of the clamp in my bench vice to hold the unit. For your purpose, sticking the clamp in a vice with the jaws as close to the tubing as you can get with room for the flaring tool should pinch the tubing nicely. Use an adjustable wrench or pliers to tighten the clamp wing nuts will help too.

A quality tubing cutter and working slowly to not collapse the tubing will cut the tubing as square as is needed without the need of filing to true up the end. The issue with your test photo on the lefthand tubing is that the tubing slid down in the clamp, and only one side properly collapsed inward. Remember that the cut edge of the tubing ends up inside the flare below the sealing point, so whether it is dead square or not within reason is of no importance to the seal. As for leaks, any possible leak that will cause immediate issues you will spot because you will be carefully watching and feeling the connection to where you won't have a fire. Keep an eye and finger on the connections at engine start-up and be ready to kill the engine. Have a rag in hand to place around a leaking connection to contain the leak. Having a quality fire extinguisher in the shop is a must, and the exhaust won't be hot enough to cause an issue before you shut down. Non of my vehicles have open sparks or poor electrical insulation in the engine compartment to cause a fire, so that isn’t a concern for me.

As for my flaring technique, I cut the tubing with a quality tubing cutter going slow in pressure to not collapse the tubing. I take a rotating pipe reamer (look in your hardware store’s copper plumbing section) and gently chamfer the inside of the tubing to deburr. The outside should have a clean, slight taper from the cutter that helps it collapse inward. Once I have the tubing mocked up in the clamp but not fully tightened, I place the die upside-down and raise the tubing in the clamp to where it is approx. 1/16" (for 3/16 line) or 1/8" (for 5/16 and 3/8 line) above the step in the die. Many instructions say to go flush with the step, but I keep the line higher especially with larger quality tubing because the line usually slides down a hair upon first compression before gripping, and having a little extra line folded down in the inverted flare won't cause a blockage or sealing issue. Look at your test photo. The righthand piece could have another 1/8 of line down in the inverted flare before it reached the ID of the tubing, so don’t be afraid to go a little longer to help get a nice flare. Once the tubing is clamped well, place the die inside the tubing. I now put a drop of oil in the die center well to allow the pointed flaring tool to easily seat and to lubricate the point for the inner flare later. Begin applying gentle pressure to the die watching to make sure the top of the tubing is collapsing inward while the side is bulging out. Stop and rectify any issue if this bending isn't happening or if the tubing is just sliding down in the clamp with no sign of stopping past the extra amount you gave yourself. Tighten down until the tubing is collapsed and you get firm resistance, but don't over-tighten or you can crack the die. Remove the die and inspect the tubing end for consistency. Tighten the flaring tool to create the inner flare. Tighten by hand until you get hard resistance. You should have no issue with quality tubing cracking no matter how hard you tighten by hand. The oil on the tip will help create a smooth, ridge-free flare. After removing the tubing from the clamp, inspect for good flares free of burs or blemishes, hit the outside of the tubing with a wire brush to knock off any zinc shavings, and blow off/out the line with compressed air after all flares are made. When tightening the fittings, put a drop of oil on the nut threads to assist with tightening. Some people use Teflon tape on the threads for lubrication, which is fine but not the most attractive.

I wouldn’t bother lapping a double-inverted flare since the steel nuts and brass fittings make their own bed regardless once fully tightened. Aside from probably the first few fittings I ever made hundreds of fittings ago, this procedure hasn’t failed me yet, so I hope it works for you too. Keep at practicing and you’ll get it soon enough.

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1960fury
Posted 2022-02-20 11:33 AM (#619598 - in reply to #619588)
Subject: Re: Hints for double flaring a new fuel line



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PolyJ - 2022-02-20 2:57 AM

Hey, 56D500boy, I have a few tips and comments to hopefully help you along.

First, you can buy 25' rolls of quality line from Jegs at good prices, which is what I do to make up my fuel, brake, and vacuum lines. In my experience, quality zinc-plated tubing flares a lot nicer than the store-bought prefabbed black/green/brown tubing. Plus, you'll have plenty of line to play with.

I also second what Wizard and Ronbo97 said about quality tools. I have both a KD kit and an older USA-made kit similar in design to your kit. Interesting, the best flares I get are using the type of clamp you have with the KD compressor that has a vise on the side to really squeeze/capture the tubing in the clamp. I put the extended tang of the clamp in my bench vice to hold the unit. For your purpose, sticking the clamp in a vice with the jaws as close to the tubing as you can get with room for the flaring tool should pinch the tubing nicely. Use an adjustable wrench or pliers to tighten the clamp wing nuts will help too.

A quality tubing cutter and working slowly to not collapse the tubing will cut the tubing as square as is needed without the need of filing to true up the end. The issue with your test photo on the lefthand tubing is that the tubing slid down in the clamp, and only one side properly collapsed inward. Remember that the cut edge of the tubing ends up inside the flare below the sealing point, so whether it is dead square or not within reason is of no importance to the seal. As for leaks, any possible leak that will cause immediate issues you will spot because you will be carefully watching and feeling the connection to where you won't have a fire. Keep an eye and finger on the connections at engine start-up and be ready to kill the engine. Have a rag in hand to place around a leaking connection to contain the leak. Having a quality fire extinguisher in the shop is a must, and the exhaust won't be hot enough to cause an issue before you shut down. Non of my vehicles have open sparks or poor electrical insulation in the engine compartment to cause a fire, so that isn’t a concern for me.

As for my flaring technique, I cut the tubing with a quality tubing cutter going slow in pressure to not collapse the tubing. I take a rotating pipe reamer (look in your hardware store’s copper plumbing section) and gently chamfer the inside of the tubing to deburr. The outside should have a clean, slight taper from the cutter that helps it collapse inward. Once I have the tubing mocked up in the clamp but not fully tightened, I place the die upside-down and raise the tubing in the clamp to where it is approx. 1/16" (for 3/16 line) or 1/8" (for 5/16 and 3/8 line) above the step in the die. Many instructions say to go flush with the step, but I keep the line higher especially with larger quality tubing because the line usually slides down a hair upon first compression before gripping, and having a little extra line folded down in the inverted flare won't cause a blockage or sealing issue. Look at your test photo. The righthand piece could have another 1/8 of line down in the inverted flare before it reached the ID of the tubing, so don’t be afraid to go a little longer to help get a nice flare. Once the tubing is clamped well, place the die inside the tubing. I now put a drop of oil in the die center well to allow the pointed flaring tool to easily seat and to lubricate the point for the inner flare later. Begin applying gentle pressure to the die watching to make sure the top of the tubing is collapsing inward while the side is bulging out. Stop and rectify any issue if this bending isn't happening or if the tubing is just sliding down in the clamp with no sign of stopping past the extra amount you gave yourself. Tighten down until the tubing is collapsed and you get firm resistance, but don't over-tighten or you can crack the die. Remove the die and inspect the tubing end for consistency. Tighten the flaring tool to create the inner flare. Tighten by hand until you get hard resistance. You should have no issue with quality tubing cracking no matter how hard you tighten by hand. The oil on the tip will help create a smooth, ridge-free flare. After removing the tubing from the clamp, inspect for good flares free of burs or blemishes, hit the outside of the tubing with a wire brush to knock off any zinc shavings, and blow off/out the line with compressed air after all flares are made. When tightening the fittings, put a drop of oil on the nut threads to assist with tightening. Some people use Teflon tape on the threads for lubrication, which is fine but not the most attractive.

I wouldn’t bother lapping a double-inverted flare since the steel nuts and brass fittings make their own bed regardless once fully tightened. Aside from probably the first few fittings I ever made hundreds of fittings ago, this procedure hasn’t failed me yet, so I hope it works for you too. Keep at practicing and you’ll get it soon enough.



It got nothing to do with the quality of the tubing cutter, if you have the slightest play with the blade (there is mostly some), it can result in a cut that is not square.

As posted before, a larger sealing surface, does not seal better, even if it sounds logical at first without thinking about it. A smaller sealing surface seals better, as it provides more pressure for the contact surface.

Also, adding more height to compensate for a slipping tube(!) is not a good idea. Once the tube slips, stop and start again. Just use quality tools and DEGREASE the contact surfaces and the tube wont slip.

Edited by 1960fury 2022-02-20 11:34 AM
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PolyJ
Posted 2022-02-20 11:58 AM (#619602 - in reply to #619598)
Subject: Re: Hints for double flaring a new fuel line



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1960fury - 2022-02-20 9:33 AM
It got nothing to do with the quality of the tubing cutter, if you have the slightest play with the blade (there is mostly some), it can result in a cut that is not square. As posted before, a larger sealing surface, does not seal better, even if it sounds logical at first without thinking about it. A smaller sealing surface seals better, as it provides more pressure for the contact surface. Also, adding more height to compensate for a slipping tube(!) is not a good idea. Once the tube slips, stop and start again. Just use quality tools and DEGREASE the contact surfaces and the tube wont slip.

 

As I said, a quality tubing cutter will cut square enough for the die to function properly. Cheap cutters have a loose cutting wheel that will wander on the tubing versus a quality one that cuts straight and true enough for the die to work.

I never said anything about a larger sealing surface sealing better than a smaller one, which does not sound logical at first to me, so I'm not following the criticism there. The double-inverted flare sealing surface is dictated by the female fitting's cone and not the tubing flare which is always a wider sealing surface. Teh tubing flare registeres on a very thin part of the female fitting cone. Having the tubing flare expand into the tubing more will have no negative impact but will give the builder some wiggle room during construction.

We will have to disagree on adding 1/16" - 1/8" tubing height during construction to compensate for the first bit of compression and any slight slippage to ensure a good flare. As I said, I have built hundreds of double-inverted flare fittings of all sizes in the professional setting with no issues, so my technique is "a good idea." Others have their own techniques, but that doesn't make a different one that is perfectly safe and works "not a good idea." Your technique works for you, mine for me, both are safe and functional, and 56D500boy is learning and asked for advice on how others perform the task. He now has two different methods.

56D500boy, give my technique a try a few times and see how it works for you. If it doesn't, you'll know.

 



Edited by PolyJ 2022-02-20 12:01 PM
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1960fury
Posted 2022-02-20 12:29 PM (#619604 - in reply to #619602)
Subject: Re: Hints for double flaring a new fuel line



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I don't know what you did, but I'm not able to "quote" your post.

Quote PolyJ:
I never said anything about a larger sealing surface sealing better than a smaller one, which does not sound logical at first to me, so I'm not following the criticism there. The double-inverted flare sealing surface is dictated by the female fitting's cone and not the tubing flare which is always a wider sealing surface. Teh tubing flare registeres on a very thin part of the female fitting cone. Having the tubing flare expand into the tubing more will have no negative impact but will give the builder some wiggle room during construction.
Quote PolyJ end

I should have said logical for "some" people. I just measured, negative on that. The sealing surface is NOT always dictated by the female fitting.

Overly stretching the flare (increasing te sealing surface) WILL have a negative impact, as the flare loses its "spring action", that adds safety.


Quote PolyJ:
We will disagree on adding 1/16" - 1/8" tubing height suring construction to compensate for the first bit of compression and any slight slippage to ensure a good flare. As I said, I have built hundreds of double-inverted flare fittings of all sizes in the professional setting with no issues, so my technique is "a good idea." Others have their own techniques, but that doesn't make a different one that is perfectly safe and works "not a good idea." Your technique works for you, mine for me, both are safe and functional, and 56D500boy is learning and asked for advice on how others perform the task. He now has two different methods.
Quote PolyJ end

A properly degreased and clamped down pipe with a quality flaring tool will NOT slip. You can't control slippage. To base a technical construct of any kind on something you can't control, is always NOT A GOOD IDEA.

Follow the instructions of the industry. They didn't comprise tubes that slip an indetermined amount, due to incorrect use of tools.
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56D500boy
Posted 2022-02-20 12:36 PM (#619605 - in reply to #619588)
Subject: Re: Hints for double flaring a new fuel line



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Thanks for all those hings Justin. Unfortunately, a bit late for me on this round. I cut down a 30" Poly Armor pre-made and flared the cut end (did at least as good as my second try). Still tweeking the bends for clearance and better fit at the fuel pump fitting.

One thing: I am in Canada and Jegs is not. Getting things up here under Covid is not easy. Hence, my trip to one of my local Friendly Auto Parts Stores (FLAPS), in my case, Lordco (Think O'Reilly's)

But thanks muchly.

PS: Great work on creating your website. You should be proud.





Edited by 56D500boy 2022-02-20 1:40 PM
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PolyJ
Posted 2022-02-20 1:22 PM (#619607 - in reply to #619605)
Subject: Re: Hints for double flaring a new fuel line



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56D500boy - 2022-02-20 10:36 AM . Thanks for all those hings Justin. Unfortunately, a bit late for me on this round. I cut down a 30" Poly Armor pre-made and flared the cut end (did at least as good as my second try). Still tweeking the bends for clearance and better fit at the fuel pump fitting. One thing: I am in Canada and Jegs is not. Getting things up here under Covid is not easy. Hence, my trip to one of my local Friendly Auto Parts Stores (FLAPS), in my case, Lordco (Think O'Reilly's) But thanks muchly. PS: Great work on creating your website.

 

Happy to help, and you can give it a try next time. Nice job on the line, especially with that tight 90* bend.

Thanks a lot for the website compliment; it's been a long process with many hours involved, but I hope it helps others. I'm going to be starting an A-block 390 stroker build this year and intend on writing an entire series from disassembly, machining, building, head workbench porting, and rebuilding the aluminum pushbutton 727 transmission. Just saving up the dough for the stroker crank, custom forged stroker pistons, and other parts.

I went out in the shop and snapped a few photos of some fuel and brake lines I made up using the technique I describe. These were already installed and confirmed to be good seals for thousands of miles of hard test driving before I dismantled the car to finish boxing/welding and painting the chassis. Notice the thin band inside the 3/8" fuel line flare and the indentation in the steel where the female fitting cone and tubing flare contacted and found their seal and that having a little additional tubing in the flare has no impact on seal or inside diameter.

 

 



Edited by PolyJ 2022-02-20 1:36 PM




(IMG_20220220_110214797.jpg)



(IMG_20220220_113837159.jpg)



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Attachments IMG_20220220_110214797.jpg (228KB - 63 downloads)
Attachments IMG_20220220_113837159.jpg (90KB - 64 downloads)
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Stroller
Posted 2022-03-05 9:26 AM (#620014 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line


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My double flaring tool I got it off a Snap On truck and have never had any issues. It hold the lines nice n tight and doesn't leave the edges showing it. Thing is just be attentive. The height of the tube in the holder should be the same height as the fitting you put in it. Just got done making a new fuel for my 360 in my '79 D150 I put a 4 barrel holley on.
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56D500boy
Posted 2022-03-06 11:39 AM (#620038 - in reply to #620014)
Subject: Re: Hints for double flaring a new fuel line



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Stroller - 2022-03-05 6:26 AM
My double flaring tool I got it off a Snap On truck and have never had any issues.


I'm sure that the Snap-on flaring tool is one of the best to use. However, around here, finding a Snap-On truck a) isn't easy and b) even then the dealer might not want to sell to the public or c) forget that you ordered something (because he didn't have one on the truck when you found him) and therefore you never get it.

At least that has been my Snap-On experience. Bad.

In this case, I just needed to make one fuel line flare so the hassle of finding a friendly Snap-On truck versus going to an actual tool store and buying the kit made the decision easy.

Store.

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57burb
Posted 2022-03-17 10:03 PM (#620316 - in reply to #620038)
Subject: Re: Hints for double flaring a new fuel line



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I'm not sure if you've finished your lines yet, but I have a suggestion. Instead of using steel lines, consider NiCopp (Nickel Copper) lines instead. It is available in rolls and uses the same fittings you already have. It costs about the same as steel, but it is much easier to bend and flare, which is good when using sub-optimal tools. The material is much more malleable than steel, so it is less likely to crack when creating double flares. And it is DOT legal for brakes and fuel systems.
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56D500boy
Posted 2022-03-17 11:23 PM (#620319 - in reply to #620316)
Subject: Re: Hints for double flaring a new fuel line



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57burb - 2022-03-17 7:03 PM
I'm not sure if you've finished your lines yet, but I have a suggestion. Instead of using steel lines, consider NiCopp (Nickel Copper) lines instead. It is available in rolls and uses the same fittings you already have. It costs about the same as steel, but it is much easier to bend and flare, which is good when using sub-optimal tools. The material is much more malleable than steel, so it is less likely to crack when creating double flares.


Thanks for that Danny. I am "done" (for now) in the sense that what I created works. However, I am not against re-doing my work to make it better. That said, I am not sure where I will be able to buy some 5/16" NiCopp tubing locally.

I will phone around tomorrow.

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57burb
Posted 2022-03-17 11:26 PM (#620320 - in reply to #620319)
Subject: Re: Hints for double flaring a new fuel line



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I expect you'll be able to purchase it from any local auto parts store, and have it within a day if they don't have it on the shelf. This is a link to some 3/16, but you can find it in all the usual tubing diameters. It is normally sold in a 25' coil like this.

https://shop.advanceautoparts.com/p/nicopp-nickel-copper-brake-line-...
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56D500boy
Posted 2022-03-17 11:32 PM (#620321 - in reply to #620320)
Subject: Re: Hints for double flaring a new fuel line



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You have to remember that I am in Canada and things that you can find in the US of A might not be as easy to find up here. That said, I will phone around tomorrow to see what is available (or not).

Getting things shipped from the US might be getting easier soon but it has been difficult with Covid.

This would work for me (30" of 5/16" NiCopp with fittings) (a 25 ft roll is too much):

https://shop.advanceautoparts.com/p/nicopp-domestic-nicopp-nickel-co...





Edited by 56D500boy 2022-03-17 11:35 PM
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56D500boy
Posted 2022-03-18 2:05 AM (#620322 - in reply to #620321)
Subject: Re: Hints for double flaring a new fuel line



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Googled and found that NAPA Canada might be a supplier. Like this:





(NAPA5_16x30NiCoppFuelLine.jpg)



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mstrug
Posted 2022-03-18 8:54 AM (#620325 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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Zoro had it: https://www.zoro.com/ags-domestic-nicopp-brakefueltransmission-line-...

Domestic NiCopp Brake/Fuel/Transmission Line, 5/16 x 30, CN-530 $8.34




Edited by mstrug 2022-03-18 8:56 AM
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56D500boy
Posted 2022-03-18 12:03 PM (#620334 - in reply to #620325)
Subject: Re: Hints for double flaring a new fuel line



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mstrug - 2022-03-18 5:54 AM
Zoro had it: https://www.zoro.com/ags-domestic-nicopp-brakefueltransmission-line-...
Domestic NiCopp Brake/Fuel/Transmission Line, 5/16 x 30, CN-530 $8.34


No Zoros or Zorros up here in the Great White North (my grass is green).

Tried NAPA, nope. Bumper to Bumper, nope.

Went back to my first choice, Lordco, with the American Grease Stick number, CN-530, and,.......

Yup. Three in the warehouse. Can have one here (their shop) in 2 hrs. Okay. Please.

American Grease Stick (AGS) also makes the steel Poly Armour stuff:

https://agscompany.com/product-category/brake-fuel-transmission-line...





Edited by 56D500boy 2022-03-18 12:04 PM
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56D500boy
Posted 2022-03-18 5:21 PM (#620345 - in reply to #620334)
Subject: Re: Hints for double flaring a new fuel line



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56D500boy - 2022-03-18 9:03 AM
Went back to my first choice, Lordco, with the American Grease Stick number, CN-530, and,.......
Yup. Three in the warehouse. Can have one here (their shop) in 2 hrs. Okay. Please.


Okay, picked up a 30" stick of CN-530 up after lunch today. Napa's price would have been $18.09 plus taxes but they didn't have any. Lordco, after a discount, was $20.91 plus taxes.

Let the games begin.

Again.



Edited by 56D500boy 2022-03-18 8:00 PM
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ISGRH
Posted 2022-07-21 8:25 PM (#623085 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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I'm an I&E technician turned estimator in my professional life, so I have fabricated and installed a fair amount of tubing in my career. In my experience most of the "mechanics" style tubing flare kits do not work well with fuel lines. Usually you will crease or tear the tubing to get it tight enough to create the double flare. This also depends on the type of material the tubing is made of an how thick the "wall" is.

About 15 years ago I had a 69' Roadrunner and I swapped the single 4-barrel carburetor for a "double pumper" 4-barrel. I needed to re-route the fuel line to accommodate the interference with the distributor. My buddy had a Blue Point (Snap-on) double flare tool and we tried making lines several times. He's a mechanic and does brake lines all the time with his tools. The best one lasted 5 minutes before it started leaking a tiny amount of fuel. Eventually after searching the interweb, I found a guy who made professional high quality pre-bent and flared lines for my engine/carburetor dilemma.

In industrial work like I encounter, we use tubing fittings with ferrules. Once you cut/bend the tubing to length, de-burr, and install the fitting they are full-proof. Once tightened to the correct thread engagement (you check this with a GO/NO-GO gap tool), the ferrule is crimped in place and will not be removable. We run all types of incredibly volatile materials (tolulene, benzene, HF acid, etc.) through these types of tubing and fittings, with no leaks. Swagelok and Parker are the major brands that are used everywhere, including Canada. These will not be factory appearing if that is your intent, but they are definitely the permanent solution. They are definitely more expensive than your parts house pieces, but that is what I would recommend.

https://products.swagelok.com/en/?gclid=EAIaIQobChMI3LLb6Z2L-QIVRm5v...
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58coupe
Posted 2022-07-22 11:32 AM (#623098 - in reply to #619392)
Subject: Re: Hints for double flaring a new fuel line



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I have used a lot of Swagelok as an aircraft mechanic and they do work well. They are used for high pressure hydraulic lines and don't leak. not cheap but but what is your car worth to you?
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