How to apply torque seal to AN and NPT fittings?

mcencula · #1 04-30-2011, 10:47 PM

Two questions:

Does anyone have a picture of how to correctly apply torque seal to an AN fitting nut?
Same question, but for an NPT fitting.

The reason I'm asking is that I've heard you shouldn't apply torque seal to threads, but I don't know how to do it otherwise in these applications.

Thanks,

RV6AussieNick · #2 05-01-2011, 12:17 AM

Torque seal is applied to the nut (AN fitting) in such a way that it will be chipped of when a spanner is placed over the nut or the fitting is turned as in removing the fitting. The main thing you want to do is have it where you can see if the fitting is loosening or has been tampered with.

If you look I'm sure there is an approved application process somewhere on the net.
Cheers,

mcencula · #3 05-01-2011, 02:41 AM

Quote:

Originally Posted by RV6AussieNick

Torque seal is applied to the nut (AN fitting) in such a way that it will be chipped of when a spanner is placed over the nut or the fitting is turned as in removing the fitting. The main thing you want to do is have it where you can see if the fitting is loosening or has been tampered with.

If you look I'm sure there is an approved application process somewhere on the net.
Cheers,

Thanks Nick. Reading your response I can see I wasn't very clear in my original question. Sorry about that. I understand it's not used as a thread sealer.

I'm trying to figure out whether the torque seal goes from the edge of the nut to the AN fitting (gets on the visible threads), or from the back side of the nut to the sleeve, or from the back side of the nut across the sleeve to the tube.

For NPT fittings...say, for example the ones screwed into the parking brake valve...Would I be correct in putting a dab of torque seal from the exposed NPT thread to the valve body?

Thanks,

RV6AussieNick · #4 05-01-2011, 03:18 AM

It doesn't really matter where it is placed, the thing that you want to achieve is that it will be visible and that if the fitting is starting to rotate or someone has tampered with the fitting/bolt you will be able to see that.

Wayne Gillispie · #5 05-01-2011, 04:01 AM

It is easy to torque a bunch of fittings and possibly forget one then apply torque seal to them all. I probably go a little overboard with torque seal as we did in the military. I run a bead across 1/8" of tube onto nut then across to fitting. I apply it to the most visible side once everything is assembled.

RV10Rob · #6 05-01-2011, 08:21 AM

Mike, to answer your question, just put to on the threads. It's not a big deal to remove the seal if you have to remove the nut/fitting later.

-Rob

Caveman · #7 05-01-2011, 08:37 AM

EAA has a video that explains the proper method:

http://www.eaavideo.org/video.aspx?v=29739769001

Sig600 · #8 05-02-2011, 12:49 AM

I think the latest EAA Mag had an article about things DAR's look for (attention to detail) and it specifically mentioned NOT getting TS on the threads, but on the nut/sleeve only.

flion · #9 05-02-2011, 08:28 AM

I disagree with this. It's one thing to not get torque seal on threads that pass through a fastener, like a nut, but if you don't put it on the threads of a fitting, where will you put it? The former case might cause galling of the threads (though most lacquer applications remain so brittle and stick so poorly I don't think it would be a problem on most areas of the airframe) but the latter has no chance to cause a problem as the fitting is already tight and the B-nut will only go away from the threads with lacquer. Of course, if it bothers you, you can always go with safety wiring the fittings, in which case you don't need torque seal.