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  1. #14
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    Jan 2015
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    If the end of the coper tube is not debureed well enough the tube will split when flared (creats a high stress stop in the copper). The potential for splitting becomes greater the smaller or thinner the tube is. If the tube is hard it will split. Many people apply too much force when flaring 1/4" tubing and cracks the copper, which is typically found when tightening the flare nut or when it is vacuum/leak checked. What makes the seal in a flare fitting. It is the conpression forces created by the flare nut on the copper tube to the fitting. Too much force by nut and fitting and the copper fails. What is the primary thing that effects torque and making a good seal? Friction. Oil reduces friction, look at a torque chart sometime find a non-lubricated and a lubricated torque chart. You will find every tme for every size the lubricated torque value is lesser.

  2. #15
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    Feb 2004
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    Any lubricant will change a torque value. Sometimes a lot. The value for a bolt with oil on the threads has a multiplier of .55.
    A flare should be oiled. This is standard procedure. A flare breaking is likely because of no oil. Even with a lubricant the torque value should be adjusted. I would expect the manufacturer should have these values.
    A problem might be had if the copper is too hard but that should be seen when the flare is being made. If this is suspect you can anneal the copper first. Heat to a dull red and let it cool naturally then flare.
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  3. #16
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    Jun 2019
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    it didnt split... it came off as a copper ring inside the fitting, with no visible split. And I'm sure the torque was correct (as specified by the manual).

  4. #17
    Join Date
    Jun 2012
    Location
    Northern NV
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    Using an automotive torque wrench with a crowsfoot? Leverage add to torque...

    The torque tool for the minis is calibrated for the supplied "crow foot"

    ...and they do spec a pot load of lb-ft of torque!

  5. #18
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    Jun 2019
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    not if you put it at 90°, then it is nearly the same

  6. #19
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    What happened to the days when a flare was simply tightened.
    Your flare broke. I imagine your flare tool is the correct angle. There are several angles out there. For a flare to appear as you said, the flared portion braking from the pipe would seem to indicate that the flare moved and the pipe didn't. The flare nut grabbed the flare and broke it. If true there was no lube. I'd inspect the brake closely with a magnifier to see the way the flare broke.
    What was the torque and did the manual specify what to lube it with. The type shouldn't matter as it's only aiding the sealing. Just to check if the manual had a torque + lube.

    I had an electrician tell me of someone tightening a flare and the pipe twisted inside the insulation.
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  7. #20
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    Jun 2019
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    btw can I double flare on HVAC lines?

  8. #21
    Join Date
    Mar 2015
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    Medford, N.Y.
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    Quote Originally Posted by BennyD View Post
    Good call. Oil is an excellent torque multiplier! I've also had a bad lineset. The tube kept on splitting at the flare every time I tried to flare it. Upon inspection, it looked like the 3/8" suction line (yeah, a small mini split) had a seam down it. Obviously a defect.

    Sent from my SM-G935U using Tapatalk
    Was the copper ,"plumbers" copper? I thought that they had seams w/ their copper?

  9. #22
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    Jan 2015
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    Iowa
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    it didnt split... it came off as a copper ring inside the fitting, with no visible split. And I'm sure the torque was correct (as specified by the manual).
    It is possible that the tubing is too hard, is it soft annealed and bent easily by hand (soft) or does kink (hard) when you try to bend it. However most times I have seen the cone break off it is because too much force was used right at the very end, you know the Umph that got it.

    btw can I double flare on HVAC lines?
    Just curious why would you want to? A double flare is for high pressure (like brakes and above 5000 psi) and usually steel and the fitting are different. I don't believe you can double bend copper without damageing in. They do make copper seal cones that go between a steel flare fitting and steel nut but these are typically used in hydraulics and greater than 3000 psi

  10. #23
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    Jun 2019
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    double flare would resist higher torque

  11. #24
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    Iowa
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    Quote Originally Posted by gustavhorna View Post
    double flare would resist higher torque
    Why do you say that? The copper is still the same thickness, The thickness whereyou explained it broke would be the same therefore no additional strength

  12. #25
    Join Date
    Jan 2010
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    Yes.
    Quote Originally Posted by gustavhorna View Post
    btw can I double flare on HVAC lines?
    Sent from my SM-G965W using Tapatalk

  13. #26
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    Quote Originally Posted by TechmanTerry View Post
    Was the copper ,"plumbers" copper? I thought that they had seams w/ their copper?
    No it wasn't, it was a lineset.

    Sent from my SM-G935U using Tapatalk
    -----Stop, step back, relax and have another go at it.-----

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