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Learning to Flare Tubing- First Flare Attempts

Saville

Saville

Well Known Member
HI all,

Well I've hit that part of the learning curve that says it's time to learn to flare.

I got myself a tube cutter, some 3/8" .049 5052 aluminum tubing, a Rolo 37 degree flaring tool, and a tube bender. I watched the Cleaveland
Aircraft video on flaring and bending, read a bunch of posts here in the forum and then did my first 3 practice runs.

Here's the results - top to bottom - first, second, third attempt:





And here is the best of the three held lightly on a male flare. The shadows make it hard to tell, but I have the impression that the flare is too long.



Any comments and suggestions about the flare attempts are very welcome.
 
The shadows make it hard to tell, but I have the impression that the flare is too long.
Click to expand...

Maybe your Rolo tool is different from mine - but mine has an arm that lets you establish proper insertion depth of the tube in the tool before you clamp the tube in place. Should prevent any too short/long problems.

I'm sure you know it is important to cut the tube square with a tubing cutter and properly de-burr and smooth it before you flare it. Looks like that may have been a problem with your first two flares but the third looks fine from the photo.
 
Dan Langhout said:
Maybe your Rolo tool is different from mine - but mine has an arm that lets you establish proper insertion depth of the tube in the tool before you clamp the tube in place. Should prevent any too short/long problems.

I'm sure you know it is important to cut the tube square with a tubing cutter and properly de-burr and smooth it before you flare it. Looks like that may have been a problem with your first two flares but the third looks fine from the photo.
Click to expand...

My Rolo is the same as yours and I used the arm to position the tube.

I forgot to mention that I also bought a deburring tool and I used that on the inside. On the outside I used a scotchpad. Though I did see one discussion that suggested using a file lightly on the outside by rolling the outside corner on the file. Maybe I'll try that next.


What lubricant do you use on the cone?
 
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If you haven't done this, put a drop or two of machine oil on the flaring cone right before flaring, and also make sure that the cone is positioned in the center of the tube. The roloflare tool does a great job but it's got some slop in it and you have to be sure it's set up just right. One other thing I do is flare a little and then back off, flare some more, back off, etc to avoid too much friction between the cone and the tube, and to ensure that oil is between the cone and the tube.
 
Saville said:
HAHAHA sorry..I should have been more explicit in the title.
Click to expand...

Fixed that for you.

By the way, looks like you need to de-burr much more than you did, also be careful to not over flair the tube.

I use a different tool, but have found simple motor oil to work well, as well as Bolube or bees wax.
 
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Saville said:
I forgot to mention that I also bought a deburring tool and I used that on the inside. On the outside I used a scotchpad. Though I did see one discussion that suggested using a file lightly on the outside by rolling the outside corner on the file. Maybe I'll try that next.


What lubricant do you use on the cone?
Click to expand...

After cutting and lightly deburring the tube, I typically would use a jewelers flat file across the end and then some purple scotchbrite to try and get the end as smooth as possible with no nicks. I also would scotchbrite the finished flare just a bit as well just to make sure there were no sharp edges. I normally used just a bit of air motor oil (marvel mystery oil) on the flare tool cone since the bottle was always sitting around for use with the air drill.

There is no need to "crush" the flare cone into the flare. It is pretty obvious when you are down as far as you need to be as the torque required will suddenly increase significantly. 5052 is tougher than the 3003 stuff that comes with the kit - but you can still over flare it.

BTW - I also used 5052 for all of the tubing on my -7.
 
fl-mike said:
Seems like a good place for some go:no-go gauges. Does anyone make them?
Click to expand...

You can use the nut as a go-no-go gauge. The tubing properly flared will not decrease the length of the tubing, and will allow the threads of the nut to just slide over the flair.

Make a clean square cut. buff the cut with a 3M wheel. Make the flair IAW the rolo flair instructions. Do not use Fuel lube.... it will hold dirt and is not easy to clean off. Use a drop of oil. Buff the finished flair to just remove the edge of the flair. If the nut does not slide over the flair, the tubing was clamped too high in the flaring tool.

A proper flair will have no ridges or scratches anywhere on the tubing or the body of the flair or the lip of the flair.
 
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