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F-35 surface fasteners: How are they maintained?


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I am trying to understand the details behind F-35 surface fasteners. In pictures of primer-only F-35s. these are immediately visible as black dots. However, these are nearly impossible to see in painted F-35s. Towards the bottom of the following link, you can see what I am talking about:

 

https://www.scalespot.com/onthebench/f35b-ita/build.htm

 

And here is the relevant pic from the above link:

Italeri+F-35B+Lightning+II+build+%252828

 

 

Reading a bit more, I came across this Quora page:

https://www.quora.com/Why-do-F-22-and-F-35-stealth-fighters-still-use-pop-rivets-to-join-the-skin-to-the-frame-while-the-B-2-used-large-robot-arms-with-spools-of-composite-fiber

 

In case not everyone is able to see the response, here it is copy pasted (red emphasis mine)

 

"Neither the F-22 nor the F-35 use pop-rivets to fix the skin to the frame. At some points they do use a special type of screw fastener for panels that need to be opened for servicing purposes, and these can produce a line of visible circles in the panel that may look like rivets. They may look like them but they definitely aren’t rivets. Once they are screwed in place they are covered in a special filler paste. Once this is properly smoothed it restores the flawless surface needed to maintain the aircraft’s stealth but the little circles may still be visible. To remove the fasteners the filler has to be taken out first. This need for filler over the fasteners every time such a panel is removed adds a fair amount of extra time to the maintenance requirements for all stealth aircraft. In some cases the edge line of the panel also needs filler and special tape on top of that.

In the case of skin panels that are not intended to be removed regularly they are mostly held in place with various types of high tech glue. This can be dissolved if the panel absolutely has to come off, but generally this isn’t necessary.

The image below shows one of the F-22 removable panels being fixed in place."

 

My question is, for the surface fasteners (and not the frequently removed panel fasteners), does the process only involve filling up the fastener heads with paste and smoothing it out and then simply painting the surface? Or are there other intricacies?

 

Also, I am curious to understand how these would age with time. if not maintained properly,  would the surface fasteners start to show in time with flaking paste or the high tech glue mentioned above, say due to thermal cycles, stress cracking, or other reasons?

 

Why am I asking this. I am planning for a highly worn out F-35 build. The existing fleet is obviously no where near that eventuality. So if I understood the mechanical realities of the fasteners, it will guide my planning process. I realize this is a what-if so I get to do what ever I want, but I remain curious about the possibilities. 

 

TIA.

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I think they are using Hi Lok fasteners which do not have a screwdriver recess in the head. but will look like a rivet from the outside.
looking at the 20 year old paint on some of our 767's, the paint often will come off the rivets leaving a nice line of bare metal fasteners.

 

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17 hours ago, Janissary said:

That's great, just the info I needed! So I'll refer those scoffing at my mad riveting of my Meng F-35 to this thread ! 🙂

 

Feel free to do what you want. But if you're looking for the worn look of a stealth aircraft, the F-22 should be your first stop. It's been in service long enough to get some of the weathering you're looking for. 

 

As for the fasteners, they would predominantly be titanium into composite skins/frames etc. and smoothed with RAM putty in preparation for the RAM exterior coatings. This fastener/composite skin structure/exterior finish does not react the same as steel Hi-Lok fasteners or aluminum rivets in aluminum structure with a commercial paint finish so I wouldn't base any weathering on an airliner. The exterior finish is critical to the stealth mission so I would be very surprised if you could discern fasteners in a properly maintained F-35. Even after years of service.

 

Cheers,

 

John

 

  

 

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You wont be seeing any rivets on an F-35 with its war paint on. Matter of fact, you would be hard pressed to see streaking as those aircraft are meticulously maintained. Those aircraft are painted by robots and would be surprised if there are tech orders detailing how to repair those fasteners should the paint come off.

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F-117 is a good study example too - that whole thing is fastened together, but when it's out doing its business - even 30 years later - there isn't a fastener head in sight for all the same reasons.

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On 10/6/2021 at 7:52 PM, Janissary said:

I am trying to understand the details behind F-35 surface fasteners. In pictures of primer-only F-35s. these are immediately visible as black dots. However, these are nearly impossible to see in painted F-35s. Towards the bottom of the following link, you can see what I am talking about:

 

 

 

Also, I am curious to understand how these would age with time. if not maintained properly,  would the surface fasteners start to show in time with flaking paste or the high tech glue mentioned above, say due to thermal cycles, stress cracking, or other reasons?

 

Why am I asking this. I am planning for a highly worn out F-35 build. The existing fleet is obviously no where near that eventuality. So if I understood the mechanical realities of the fasteners, it will guide my planning process. I realize this is a what-if so I get to do what ever I want, but I remain curious about the possibilities. 

 

TIA.

 

You wont see them, there will never be anything to weather.
It wouldnt get past the Quality Control.

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  • 9 months later...
3 minutes ago, PuikMouy said:

I think they are using bolts specifically designed for this particular fighter. I am sure they are highly resistant to wear since all the bolts are under a lot of stress during flight. Even during construction, it is important to use strong bolts that can hold much weight. I have worked as a builder for a long time and always buy fasteners here at scrooz.com.au, and for a good reason. This online store has many models of fasteners; especially nice that they are sold at a reasonable price. 

they arent aircraft specific; having worked on the F-35 center wing in Marietta years ago, I can pretty much tell you they are the same ones youll find on any lockheed aircraft...but still wondering why you are advertising a bolt store in Australia. Why??

Edited by utley
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36 minutes ago, PuikMouy said:

I think they are using bolts specifically designed for this particular fighter. I am sure they are highly resistant to wear since all the bolts are under a lot of stress during flight. Even during construction, it is important to use strong bolts that can hold much weight. I have worked as a builder for a long time and always buy fasteners here at scrooz.com.au, and for a good reason. This online store has many models of fasteners; especially nice that they are sold at a reasonable price. 

 

Spammer.... reported

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There are also times where the test or training aircraft will fly with some panels that have fasteners and seams exposed as it is not critical to have everything buttered up for what they are doing.  Or they may need to be in and out of a certain bay for other reasons so they leave the coatings unfinished for a time.  I have seen this on F-22, F-35 & B-2.  

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  • 2 months later...

CF104 & Spook498 pretty much nailed it with their posts. I don't work on RAAF -35's but I do work on one of our Army helo types, of which the body is coated in a IR paint. Most of our panels are secured by either cadmium-plated tech screws (aka as torque screws) or turn-loks. Almost always when these fasteners are swapped out with new BDS, we don't putty over them but they do get coated with the airframe paint. 

I ack not the same a/c but the concept of maintaining the integrity of the IR function of the airframe remains. 

Hope there's something in my post that helps

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