S

Stewie

Well Known Member
Patron
Hi all-
I just looked in AC43.13 to find out about when/where to use torque seal, but I was not able to find any mention of it, and also perused VAF. I have seen the EAA video and read through posts, so I understand HOW to use it, but curious if there is some SOP of use. For example, I am currently bolting my ribs to spar, with nylon locknuts. Is the use of torque seal on self locking nuts unwarranted? Or do you just stripe every single nut on the plane? Curious for any suggestions.

Thanks,
Eric
 
Eric,

I torque sealed ALL nuts that require a "Torque" (which is about all of them).

It also is a way for you to be sure you have applied the proper tightness or torque to ALL nuts so you don't miss anything along the way.

So, I guess the answer I would give is to leave no nut dry!

Some people think I painted my airplane! But I didn't it's all torque seal :D
 
Lock-tite too?

What about Lock-tite or other bolt thread gluing compounds. Is anyone using this too, or simply relying on the torque and check frequently technique. (not to say you would check any less, just seems that it would help prevent loosening).
 
where to use...

Hello, here's my 0.02 on the subject.
On those spar nuts and the ones securing the tail surfaces I would use it after finally assembly. It can be checked at the annual inspection.
On the planes I work on (some Beech King Air's) I've seen it on B nuts on fluid lines, in some cases it's been on the fittings in the innards of the plane for twenty years and has not moved.
Wheel bolts, the ones that secure the two wheel halves together is another location that I would recommend.
If the fastener gets lock wired or cotter pinned it's not really necessary, but like the video indicates it can be a good item to check on your pre-flight. Generally it's used on B nuts and self locking fasteners that don't have a visible locking mechanism, ie. lock wire or cotter pins.
The jam nuts on the rod ends of the flight control pushrods would be another good location to use torque seal.
Hope this helps.
Phil
 
I use torque seal on every fastener to indicate to myself that it is finalized. If I see something without torque seal on my airplane, I question whether or not it has been properly tightened. In other words, I use it more as an indicator that proper attention has been given to the fastener than to see if a fastener has moved.

We use locking fasteners, so I do not generally use loctite. It is an option of last resort since it depends on cleanliness, and cannot be visually verified like the presence of a locking fastener can.
 
All great replies

I can't add much to the excellent replies other than to say I always have spare tubes of torque seal in my toolbox and use as described in the posts. I have tubes of each color but I always seem to use the yellow.

That said....I'll put on my EAA Oshkosh Judges hat on and offer this to those of you who enjoy sharing your planes with the Judges and on lookers: Judges appreciate builders that pay extra attention to detail and SAFETY. Torque seal is used as a safety precaution and fastener 'indicator' and is VERY MUCH appreciated by the Judges. Something to think about if/when you pull the cowl for 'the guys with the hats'. Also, and very important....'if' you use the torque seal, be sure that it is applied properly as shown in the EAA video....otherwise you may as well have left your cowl on :rolleyes:.

Link to the EAA torque seal 'hint for homebuilders' is here:

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

Last i checked, Lock-tite was not approved for aircraft use. But I am an old fart, maybe it is OK now, but not on my bird. JMHO
 
johnny stick said:
Last i checked, Lock-tite was not approved for aircraft use. But I am an old fart, maybe it is OK now, but not on my bird. JMHO
Click to expand...

I had some as a part of a FAA/PMA kit to hold an oversize sleeve on a slightly worn torque tube.

It is "approved" for certified aircraft when called out by approved documents....
 
ppilotmike said:
What about Lock-tite or other bolt thread gluing compounds. Is anyone using this too, or simply relying on the torque and check frequently technique. (not to say you would check any less, just seems that it would help prevent loosening).
Click to expand...

Just to be clear, torque seal is NOT used to lock a fastener, but is used as an indicator, whether it is to mark fasteners that have been torqued, or to make it obvious if it loosens (torqe seal is brittle when cured and will crack if the fastener moves).
 
longranger said:
Just to be clear, torque seal is NOT used to lock a fastener, but is used as an indicator, whether it is to mark fasteners that have been torqued, or to make it obvious if it loosens (torqe seal is brittle when cured and will crack if the fastener moves).
Click to expand...

Thank you for getting to that important point. If it helps you inspect the airplane or as a means to keep track of your maintenance, then it's good stuff. The application of "bird stuff" (the technical term) does NOT increase the strength, "tightness" or security of the fastener in any way, shape or form.

I have been working on airplanes big and small for 25 years, and I can probably count on one hand the times I've used the stuff.
 
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longranger said:
Just to be clear, torque seal is NOT used to lock a fastener, but is used as an indicator, whether it is to mark fasteners that have been torqued, or to make it obvious if it loosens (torqe seal is brittle when cured and will crack if the fastener moves).
Click to expand...

Understood. I was referring to using Lock-Tite on the threads, not the Torque Seal. I guess there's no reall good way to know how the Lock-tite would react with the nylon lock nuts and such. Perhaps it would be a better thing to use locknuts that have a steel locking insert instead of the nylon ones. Or perhaps castelated nuts for everything! Helps ensure no movement better than the locking nylon alone. Besides relying on torque-seal to indicate movement only helps on the ground.
 
Toobuilder said:
Thank you for getting to that important point. If it helps you inspect the airplane or as a means to keep track of your maintenance, then it's good stuff. The application of "bird stuff" (the technical term) does NOT increase the strength, "tightness" or security of the fastener in any way, shape or form.

I have been working on airplanes big and small for 25 years, and I can probably count on one hand the times I've used the stuff.
Click to expand...

Michael, I think the use of the Torque Seal as an indicator is best thought of as an assembly practise rather than the maintenance practise you mention.

Most builders have many of the bolted parts on and off many times in their construction cycle. The use of yellow bird s**t is a valuable method for indication to the builder, as well and any future inspector, that a specific bolted joint has been torqued to a final value with flight hardware.

On every plane I have done a pre-final inspection on I have found a loose bolt/nut. In some cases the builder says "I haven't got around to that area yet..."

Homebulding is different from professional maintenance in this case. The yellow stuff is one of the cheapest safety devices at $1.95...:)
 
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When I built my -6A. I kept a supply of non locking hardware store nuts in every size required. I never put on an aircraft nut until the final assembly and torquing of an item.

That way saves a bunch of time and nuts, since it is not a great practice to use an aircraft nut over and over.

Bruce Patton
RV-6A 596S flying since '98
HP-18 5596S flying since '89
RV-10 9596S (reserved) to be ordered 1/30/12
 
Gil -

That's a valid point and I appreciate your perspective. My personal work around for assembly is to make sure that if it looks tight, it IS tight. In other words, if I'm bolting on a component within a larger maintenance process, the fasteners are either obviously loose, or flight worthy - no in between. Even if I know something is going to be taken off later, it will be ready for flight. This may not be as effective as torque stripe for some people but it works for me.

As for self locking hardware, it is general practice to discard non metalic locknuts after one use. That's why I try to use metal lock nuts wherever possible.
 
ppilotmike said:
Understood. I was referring to using Lock-Tite on the threads, not the Torque Seal. I guess there's no reall good way to know how the Lock-tite would react with the nylon lock nuts and such. Perhaps it would be a better thing to use locknuts that have a steel locking insert instead of the nylon ones. Or perhaps castelated nuts for everything! Helps ensure no movement better than the locking nylon alone. Besides relying on torque-seal to indicate movement only helps on the ground.
Click to expand...

Mike,

It sounds as though you don't quite trust nylon lock nuts. There's no reason for that; a properly torqued nylon locknut isn't going to loosen on its own - at least on the non-engine side of the firewall - that's where you use the steel locknuts. A castellated nut won't necessarily maintain torque either; usually those are intended to be used in applications where you don't torque the nut to full spec for the fastener size, like pivots, pulley shafts, axle nuts, etc.
 
Nylon locknuts

I build very high dollar flight hardware for someone else. The aerospace grade nylon locknuts are different than the cheapo ones you find at home despot.

The aerospace nylon lock nuts work by keeping the threads engaged during vibration. The nuts literally pull themselves into thread engagement as they are tightened. The cheapo home depot nuts just produce a friction that makes the nuts hard to turn, sometimes they work sometimes they don't. I have seen the cheapo nylon lock nuts come loose. Same thing applies for the metal type locknuts too.

If you are going to use locknuts, I recommend you use the aerospace grade type that work in the proper way by ensuring engagement of the threads, and not just by creating friction.
 
Locknuts

Unfortunately, the hardware I use is all stainless and titanium and a little too expensive for normal airplane stuff. I am not sure what the current part numbers are, but any good aircraft store (aircraft spruce) has the good stuff. You can tell the good nylon locknuts because as you install the nut, the nylon goes from the shape of a flat washer with a hole in it, to a dome shape. The dome shape is what provides the force to keep the threads engaged during vibration and such.
 
Torque Seal

Torque Seal is great for assembly completion, (prior applied torque verification.)

Torque Seal is also great for future inspection. As an example, I have seen a loose starter attachment nut on a friend's RV as I was assisting with his condition inspection. He swears that he torqued all nuts when installed. Vibration possibly?? There was no Torque Seal or simular visual inspection aid applied. Torque seal applied would have alerted him as to the nut being loose. It was not visually obvious that the nut was loose, although the case of prior applied torque seal would have made the loose nut mentioned, visually obvious. If neither of us would have seen the loose nut, the cowling would have been replaced and placed back into operation with that loose nut. Many of us have experienced or heard stories of the fact that on occasion this happens with general aviation aircraft after professional maintenance. Been there.

Torque Seal, when dried is a brittle enamel of various available colors that is only a visual inspection aid. If the properly applied line is broken then further inspection and correction is needed. I use it for a reliable visual inspection aid. I like the visual advantage.

Note: Not utilized on certified aircraft. (Rare exceptions.)
 
I had another much more experienced pilot do my first flight. When we were discussing things he notified me that he would be doing a VERY thorough inspection prior to first flight and he insisted that all torqued nuts have inspection lacquer/torque seal on them so HE could verify that nuts had been torqued. I use it as Guy first described, as a verification/process reinforcement.

As an aside, all those parts that come on and off many times...it seems that there is a law of the universe that when you think it's the final time and use torque seal, there will ALWAYS be one more cycle of removing and reinstalling:eek: You will quickly understand why you don't want to contaminate the threads with torque seal, if you can help it:D

All best

Jeremy
 
Torque Seal on Electrical Components?

Hi All,

Should torque seal be used on electrical components (master relay, starter relays etc)? Part of me wants to torque mark everything to be sure I've got things covered, and the other part of me doesn't think it's such a good idea to be putting dobs of anything potentially flammable compound on high current electrical components. To date I've just put a mark with a permanent marker on electrical items I have torqued.
Thoughts?

Tom.
 
tgmillso said:
Should torque seal be used on electrical components (master relay, starter relays etc)?
Click to expand...

If you want to, sure.

Part of me wants to torque mark everything to be sure I've got things covered...
Click to expand...

Your wrench ensures the fastener got torqued. The paint is for purposes of inspection at some later date, i.e. to indicate (at a glance) if it has subsequently moved, and that's all it does. I have no idea why anyone would believe it guarantees a fastener has been properly tightened. When I see torque seal on a fastener, it only tells me the builder was diligent about putting torque seal on fasteners, not that he knew anything about the correct torque and/or preload, or actually installed it that way.

Again, it's good stuff for its intended purpose, a visual indication that the fastener did or did not move in service. Applying it as an indication of special attention to the fastener is a plan with human factors issues, meaning it guarantees nothing.
 
I completely agree with Dan on this. Without reading the entire thread, I will share my use of torque seal. When I am building, I put torque seal on a fastener only immediately after I have personally torqued it (or seen somebody torque it). It is for the purpose of reminding myself that I have torqued it.

In most cases, a bolt that is subject to loosening, at least as designed by the great engineers at Van's, gets a cotter pin. For me and my work, the cotter pin serves the exact same purpose as torque seal for inspection purposes. It means that the bolt was torqued. The difference for later inspections is that the cotter pin shows that the bolt was torqued and it hasn't loosened, while the torque seal shows that it was torqued.
 
DanH said:
If you want to, sure.



Your wrench ensures the fastener got torqued. The paint is for purposes of inspection at some later date, i.e. to indicate (at a glance) if it has subsequently moved, and that's all it does. I have no idea why anyone would believe it guarantees a fastener has been properly tightened. When I see torque seal on a fastener, it only tells me the builder was diligent about putting torque seal on fasteners, not that he knew anything about the correct torque and/or preload, or actually installed it that way.

Again, it's good stuff for its intended purpose, a visual indication that the fastener did or did not move in service. Applying it as an indication of special attention to the fastener is a plan with human factors issues, meaning it guarantees nothing.
Click to expand...

Jesse said:
I completely agree with Dan on this. Without reading the entire thread, I will share my use of torque seal. When I am building, I put torque seal on a fastener only immediately after I have personally torqued it (or seen somebody torque it). It is for the purpose of reminding myself that I have torqued it.

In most cases, a bolt that is subject to loosening, at least as designed by the great engineers at Van's, gets a cotter pin. For me and my work, the cotter pin serves the exact same purpose as torque seal for inspection purposes. It means that the bolt was torqued. The difference for later inspections is that the cotter pin shows that the bolt was torqued and it hasn't loosened, while the torque seal shows that it was torqued.
Click to expand...

And I full agree with Dan and Jesse with one exception.....
I have learned that in some specific circumstances even the presence of a cotter pin doesn't mean the bolt is still fully torqued.....

A good example on an RV is engine mount bolts. Typically the bolts attach the engine mount through a sandwich of structure (firewall, aluminum spacers and angles, and then a steel bracket). it is fairly common for the initial torquing of the bolts to not fully seat all of these parts tightly to each other, but the loads imparted by flight hours does (particularly on a tail dragger engine mount because of the landing gear loads (except for RV-8)).

I recommend in my condition inspection forums that at at least the first condition inspection, highly loaded critical fasteners (engine mount, landing gear, wing, etc.) be checked for proper torque value. You wont automatically find some loose but it is fairly common. After the initial check it is far less likely to find any loose but not a bad idea to still check.
If you own an RV that these have never been check... particularly if you are the second or third owner since you have no way to know if they have been (unless someone like Walt has done a condition inspection on it at some point), I recommend that the torque on all critical fasteners be checked.

BTW, in our shop we only use torque seal to confirm that at some point one of us three full torqued the fastener so that during final inspection after the work being done is completed, it is easy to confirm whether anything was missed. This is particularly important during a new airplane build with more than one of us working on it.
 
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