JENSWAY

JENSWAY

Member
Hi all, I am sitting in my hotel room staring at my RV empennage boxes I have just had delivered to the room!

A short while ago I got off the horn to a friend who said that pre heating the rivets and then dropping them into cold water will soften them up and make riveting easier and therefore less likely to hammer aberrations in the skin. I don?t want to start something here that Van hasn?t sanctioned but could anyone give me some advice?
 
Rivets

NO!

KISS- Keep it simple __!

When you deviate from the plans and normal procedures you go off into the unknown. More trouble, unintended affects,etc
 
read up and become informed

Before you start, you should get some books on standard practices and approved methods. Get some help from someone who knows these things. Building a safe airplane requires some basic knowledge and skills that can be easily learned, not following acceptable practices will cause you grief later on.

Good Luck

CM
 
.....make riveting easier and therefore less likely to hammer aberrations in the skin....
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Forgoing your friend's well-intentioned advice, I'd be reluctant to alter the mechanical properities of rivets on an ad-hoc, home handyman basis. How do you insure quality control? I'm afraid your friend's thoughts may be based upon HIS observation and experiences. We cannot know the quality of the equipment he used or how skilled he was using that equipment. Those things can make a big difference. A good rivet gun teamed with an appropriately sized bucking bar and deft touch while setting those rivets is key to an easier riveting experience and go a long way towards avoiding hammering aberrations into the skin.
 
I seem to recall that this has been done before. The process is called annealing. But it is not clear what affect it will have on the strength of the riveted structure; do you really want to take a chance with your arse sitting inside? A true analysis of this is beyond most of us; better to stick to what Van's calls for. Besides, the -3 rivets drive easily in any case. The usual culprit for dings and 'smilies' is not the rivet but the gorilla using the gun and/or bucking bar. Practice on scrap and take reasonable care and you won't have a problem.
 
Heating Rivets

Pre-heat rivets? Not necessary!

If you look at the average spam-can, you will see that Van places the rivets closer together (more rivets) than the certified aircraft. No one has said this, but I think Van anticipated that the riveting out there in the field might not be perfect. Therefore, additional rivets were designed in to make up for less than perfect technique. In other words, the RV's are a bit overbuilt!

Relax and enjoy your project. If you build it with pride, and a burning desire to do as well as you can do, your RV will turn out fine!
 
Please do not do this. Most of the structure of our RVs is fastener shear critical, not material bearing critical. Altering the structural properties of your rivets is a recipe for premature structural failure.

The bad thing about fastener shear critical structures is once one rivet is overloaded and fails, the others in that same joint try to pick up the load that the broken fastener used to carry, and they fail as well. In short, the entire joint "unzips" almost instantaneously.
 
Rick6a said:
Forgoing your friend's well-intentioned advice, I'd be reluctant to alter the mechanical properities of rivets on an ad-hoc, home handyman basis. How do you insure quality control? I'm afraid your friend's thoughts may be based upon HIS observation and experiences. We cannot know the quality of the equipment he used or how skilled he was using that equipment. Those things can make a big difference. A good rivet gun teamed with an appropriately sized bucking bar and deft touch while setting those rivets is key to an easier riveting experience and go a long way towards avoiding hammering aberrations into the skin.
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^^^This. Plus a good pnumatic squeezer.
 
You must be kidding

This sounds like an April Fools Joke! The uncontrolled adjusting of the mechanical properties of anything holding your A/C together sounds pretty crazy to me and I've been around the barn more than once.
 
It's called solution heat treating and is not necessary. It also requires rather high temperatures and very accuate temperature measurements.

I tried it on some rivets back in the 90's and then shear tested them. They came out dead on the book value for shear strength. "As received" rivets tested higher. The treated rivets age harden back to "normal" in a day or so.

One issue that I noticed was that dome head rivets would tend to "flow" into the rivet set on the manufactured head. The aluminum was so soft it would squish into the cup and leave a "ring". Flush heads would end up with no dimple on the manufactured head. Sure made those #4's easy to set though!

As others have said, don't bother.
 
Ice box rivets

Sounds like your friend is talking about DD rivets, which are made from 2024 aluminum. The rivets in the kit are AD, which are made from 2117 aluminum, and are designed to be driven as received. DD rivets do go down like butter, but heat treating them requires an oven that maintains between 910 and 930 degrees. This is not annealing. I believe they are considered condition W after quenching, then they are put on dry ice. This keeps them from aging to there normal hardness. They are kept cold until ready to shoot, then you have about 10 or 15 minutes before they start to noticeably harden. That takes between three and four days.
TMI?
 
You have a long build ahead of you, don't get slowed down with this rivet issue, the riveting is the easy part!
 
After 3 years of "slow-assembling" an RV-9A QB, I have this general advice: Ignore almost all advice you get...certainly at first. Stick to Van's documents, instructions, and plans. Use well-accepted, published references. Take one of the empennage construction courses if you can, best money you will spend.
 
Excellent advice

Buggsy2 said:
After 3 years of "slow-assembling" an RV-9A QB, I have this general advice: Ignore almost all advice you get...certainly at first. Stick to Van's documents, instructions, and plans. Use well-accepted, published references. Take one of the empennage construction courses if you can, best money you will spend.
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Excellent advice! I second this.
 
I think your bigger challenge is to build in a hotel room. Other then that you should not need to go to such length.

I know of some one that used this method for his RV7, for the trailing edge of the rudder to get nice shop head. Well, with a bit of care, mine came out just as nice if not nicer using the standard method. So, I guess what I am trying to say is that such alteration from standard method is not needed even in the more challenging area.
 
Wow, this goes back to the Dave Anders RV4 days of annealing. This was before most builders knew about back riveting. Buy a nice backriveting set.
 
Cooked rivets

I have set "cooked" rivets as we called it. An AD rivet heated in a controlled oven can be annealed after reaching a precise temperature, quenched in water and driven within 30 minutes and it works well. Our oven was a small industrial oven with two precise thermometers and we had precise controls meaning it was a very expensive item. This is done with large rivets none of which are used in the RV series aircraft but they could be set very easily with light equipment in tight places because the rivets are so soft. They do harden right back to their preannealed strength but it takes a few days. They also should be set soon after quenching meaning it is slow work. It should not be done without the proper equipment and there is no place for it in any RV or most other small aircraft.

Dick DeCramer
RV6 N500DD
RV8 fuselage
Northfield, MN
 
Heat treated rivets

Rivets, where do I start, there is a myriad of materials and types of application for rivets, way too much to go into here, discussion about AD rivets on the VAF are just scratching the surface of the rivet world. I've been working on large airliner aircraft for 21 yrs and I'm still learning about rivets.

I'm reading this thread and wondering why you would want to or even need to heat treat or as stated soften AD rivets.

AD rivets are easy to put down, so really there isn't a need to heat treat them. A very real consequence is that you will end up with a load of annealed rivets in your aircraft that don't age harden like properly heat treated DD rivets, instead you have an aircraft constructed with soft annealed rivets, not a good situation.

Heat treating any form of alloy either rivets of formed parts should be done under strict conditions by trained operators with the proper testing equipment to ensure the process has been carried out correctly. The most common alloy used in aircraft is 2024 T3, this also comes in annealed (soft) form designated as 2024 O, this material is used to fabricate parts from, usually complex angles or Z sections, then they are re annealed to remove any induced stress then heat treated to a exact temp for a specified time depending on thickness, then water quenched to set the grain and finalise the heat treating process, other alloys can be heat treated, 7075 T6, the list goes on and on.

If you know someone who is an aircraft engineer, aircraft sheet metal worker who works for a large repair organization specialising in big transport aircraft, ask them to fill you in on the process or look up heat treating aircraft grade alloy on the net, there is a lot too it.

Happy building guys, lets build them safe and strong as the designers intended.

Nick..
 
Sorry guys, it's not annealing.
Solution heat treatment is not the same as annealing.
Different temperatures and cooling processes.
http://www.mlevel3.com/BCIT/heat%20treat.htm

It's pretty much a moot point since we have established that it is not necessary, but I don't want to have someone annealing rivets.
 
Eighty years of building aluminum airplanes and probably tens of billions of rivets pounded.......those are pretty good statistics! I'd stick with the standard practice. Besides, after the first one thousand rivets, your fingers would be cooked!

CDE
 
annealing

While we are on this subject, I have been using a very unscientific, imprecise method to anneal the washers that goes under the sparkplug each time I change my plugs.

Any one can see any issues with this?
 
no problem

I believe what you describe is fairly standard practice for an entirely non-structural part like a crush washer, and would be recommended.
brian
 
Squash em flat

Setting a rivet is like .05% of the complexity of building one of these. Figure it out, do it well, move on. If you have to pound it flush from the inside, then do it.

Sanding your rivet line prior to painting is another story. Sealing your oh, so perfect rivet line as to not have gaps in the paint, and not looking like a bondo buggy, is yet another story. Riv's are the easy part.
 
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