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Charlie,
The wire from the fitting in the photo was rounded and smooth on the ends. The length was such that a little over 1/16" was still in the insertion hole and not bent. All the fittings were that way as were fittings from other vendors which did not exhibit
problems.
I did contact S. I. and their response was that the fittings could be returned for credit if in "as new" condition which, of course they are not.
Were the hose ends you used straight and not angled? If so, the rotation of the fitting along with the nut may not have been so noticeable. This would result in torque applied to the hose which would tend to loosen the connection when placed in service.
Hopefully, my experience is unusual and your connections are not at risk.
Steve
From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Charlie England <ceengland7@gmail.com>
Sent: Monday, April 07, 2014 3:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: AN 10 PTFE hose and fittings
On 4/7/2014 1:11 AM, Steven W. Boese wrote:
At the end of November last year, I responded to an inquiry from Charlie concerning AN PTFE hose and fittings from siliconeintakes.com. I stated that my experience with their products and service was positive but that I had not specifically tried their
hose and fittings.
I now have some experience with their AN10 PTFE hose and fittings as shown in the attached photo. The fitting is manufactured by placing the blue nut on the red fitting and inserting the heavy wire through the hole in the nut. The wire captures the nut
and allows it to rotate relative to the fitting. When the tapered part of the fitting first contacts the male end to which it is being connected, the fitting cocks sideways in the nut as seen in the left side of the photo. If the nut is tightened further,
the fitting rotates with the nut and thus maintaining proper alignment of the angled fitting is nearly impossible. If the fitting is restrained from rotating, the wire inside the nut digs into the fitting and then comes out of the back of the nut with the
results as seen in the right side of the photo. I have used fittings of similar design from other vendors successfully. Apparently the dimensions of the wire or the grooves in the siliconeintakes nut and/or fitting are not correct, or the aluminum alloy
used is too soft, or there may be some other defect. I tried installing two 90 degree fittings and two 45 degree fittings and all of them failed.
Steve Boese
RV6A, 1986 13B NA, RD1A, EC2
Hi Steve,
Thanks for the update; that does not sound like good news. I have made up all my hoses using their PTFE hose & fittings, & haven't had any problems with them, though they haven't seen any pressure yet. I did get one -10 fitting that had a scratch on the metal
tube (they promptly replaced it without charge), so this morning I pulled it apart to see if I might have similar issues. The end of the wire insert in mine is nicely rounded so it will follow the groove when inserted, and I haven't seen any evidence of the
fittings tilting over when tightened.
Have you contacted S. I. ? I wonder if they might have gotten a batch of fittings with bad wire inserts. Maybe the wire was too long & wedged into itself when it was inserted in the fittings you got.
Thanks again for the info, & please keep us updated.
Charlie
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