R

redwoodcstrvr

Member
This is my first posting. I'm assembling the empennage for a RV-9A and looking at the possibility of annealing the rivets before installation. I have talked with RV builders who have used this procedure on each of the airplanes they have built and all were very pleased with the ease of driving this type rivet. Their annalogy was "it's the difference between slicing butter right out of the refrigerator and butter that was at room temp". The key to proper annealing is temperature control, time at temperature and rapid quenching. I have the tools to do this. The one builder I have talked with has even accomplished a series of destructive tests and found that the strength of the rivets after annealing were equal to or better than the Alcoa stats. I know that Van does'nt recommend any change in procedure or modification to his kits primarily for potential litigation issues. Would really appreciate any input pro or con.
Thanks
 
I say waste of time ...

I'm pretty sure this has been discussed before, and if I remember right, about half the people thought it was a good idea, and half thought it was a waste of time. I fall in the "waste of time" camp.

Driving rivets is a simple skill that can be learned in under an hour of practice. The rivets are designed to be driven straight out of the box (or bag, or whatever). They require no further preparation, other than to ensure that they are the correct size (width and length) and type. Although rivets may be easier to set after being softened a bit, I have to believe that the time spent annealing them will far exceed the benefit that you get from the annealing.

But, that's just my opinion.

Tracy.
 
Welcome to VAF!!!!

redwoodcstrvr said:
This is my first posting.
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Frank, welcome aboard.

Good to have you here, your questions will surely get answered soon.:rolleyes:
(Will give you a chance to choose the answer you want??)

MY dos centavos-----anneal them for really thin skins, or for fiberglass. Beyond that is just not necessary.
 
Mike S said:
Frank, welcome aboard.

Good to have you here, your questions will surely get answered soon.:rolleyes:
(Will give you a chance to choose the answer you want??)

MY dos centavos-----anneal them for really thin skins, or for fiberglass. Beyond that is just not necessary.
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For fiberglass parts, nutplates and non structure parts, you can use 426A and 470A rivets. They are soft and have no dimple in the head.
 
I'm probably 75% (or more) done with the rivets on the -9A and I can't see why you'd want to do this. With good tools riveting is just not that hard. Back when I started the tail I dreaded the rivet gun (dent-o-matic). Now I find it as easy to shoot/buck or squeeze rivets. I only occaisionally have to drill one out.

I think the time you spend annealiing would be better spent building... but that's my opinion.

dave
 
I understand that annealed rivets will require less force to squash, but unless you're planning on setting them with your teeth, I can't see how it will make things any easier.

Having said that, if I had it to do over again, I would spend the bucks and get one of those nifty tungsten bucking bars.
 
szicree said:
Having said that, if I had it to do over again, I would spend the bucks and get one of those nifty tungsten bucking bars.
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You got my vote there - buy the tungsten bar and forget annealing the rivets.
 
I bought one of the Webster tungsten bucking bars pretty early in the project, and am glad I did. Every once in a while I try to use one of my older steel ones and it always surprises me how much more effort they require.
 
The "standard" 'AD' (2117D) rivets are intended by design NOT to be heat treated before use.

See Table 4-8 Aircraft Rivet Identification on page 4-17 of AC 43.13-1B Chapter 4 for details of rivet types that DO need to be heat treated before use. This table also shows shear and bearing strength of the various rivet types.

Personally I couldn't be bothered with all the fuss of using rivets that require heat treating. But if you want to do it, source the correct rivets and you'll be fine..... but your project will take you longer to complete than it need.

I bought some tungsten bucking bars from Johnston Tools (http://www.johnston-tool.com/ ). Choice, pricing and service were all very good.

Steve
RV-7
UK
 
p.s. The small JT106 and JT107 tungsten bucking bars are currently advertised at $75 each on the Johnston Tools website.
 
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Time hardens rivets ?

I believe this is a hold over from the 80's when new plane sales tanked and there wasn't near the homebuilt market as now. Rivets were sitting on the suppliers shelves for very long periods of time and from what I'm told that hardens them. Annealing became a homebuilders way of getting them soft again. This isn't going on now and there shouldn't be any reason too do this now. The very thin skin post is the only thing I see to remotely justify this now. If thing's slow down again because of the economy after a couple years you might start finding hard rivets again, but I think supply will slow minimizing this. If I remember right I read this many years ago in a Aviation mag about the time = hardening thingy. Gene
 
Thanks for all of your inputs

It was interesting to read each comment regarding my rivets question. Looks like the overall opinion on annealing is, "why?... it's a waste of time". I may try annealing some rivets when I have a hard to reach spot on the skin. I'll also look into getting a tungsten bucking bar. Thanks again!
 
One other consideration is that it is a bit of a sensitive process. If I remember correctly (and I may not) the temp range to do it properly is not very wide. You need to be able to measure and control the temp very closely or you could produce a bunch of sub standard rivets.
 
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