Do Old Rivets Go Bad?

[ncarmon]

After finishing my HS and VS 3 years ago, I'm back full steam. Something sticks in my head that I shouldn't use old rivets.

Do old rivets go bad?

Thanks.

[fmarino1976]

I would have no problem using old rivets as long as there is no corrosion on them.

Edit: I just re-read the heading on this post and might be confusing. I meant: yes, you can use old rivets. I am not aware that the heat treatment of the rivets change with time. Maybe David's rivets from Boeing were a different alloy?

[cytoxin]

but i have some that are 20 years old that i squeezed last year and they went in fine. no telling how old they were before i got them.they were military surplus.

[David-aviator]

Originally Posted by ncarmon

After finishing my HS and VS 3 years ago, I'm back full steam. Something sticks in my head that I shouldn't use old rivets.

Do old rivets go bad?

Thanks.

Yes they do. They get hard (harder). There is a procedure to heat them back to original softness but I don't know how to do it.

I once bought some rivets at the Boeing surplus store in Seattle, they were very hard and useless as I could not get them to set properly.

[terrykohler]

To optimize strength of rivets, they should be solution treated after forming and then stored at low temperature (freezer). Aluminum will age harden at room temperature, not only increasing in hardness but also strength. Artificial aging can be accomplished by minor increase in temperature over ambient. In many cases "old" rivets may be installed functionally, but the higher hardness may lead to cracking when the shop heads are formed. Contrary to an earlier post, I would not recommend that you try to solution treat your rivets without a proper metallurgical furnace, temperature controls, and protective atmosphere.

[mannanj]

Common AN470/426 AD-- -- rivets, the ones with the dimple should be ok even after many years.

I remember that years ago there used to be what was known as "refrigerator rivets" that had to be kept in cold storage until they were shot. They would definately age harden if not kept cold. Can't remember the alloy or nomenclature but they were not "AD" rivets with the dimple. (These may have been what you had from Boeing, David.)

Someone with up to date knowledge or reference material correct me if i'm wrong.

[GAHco]

Originally Posted by mannanj

Common AN470/426 AD-- -- rivets, the ones with the dimple should be ok even after many years.

I remember that years ago there used to be what was known as "refrigerator rivets" that had to be kept in cold storage until they were shot. They would definately age harden if not kept cold. Can't remember the alloy or nomenclature but they were not "AD" rivets with the dimple. (These may have been what you had from Boeing, David.)

Someone with up to date knowledge or reference material correct me if i'm wrong.

Icebox rivets are double D "DD" and I beleive they have two dashes on the head?

These are supposed to be annealed (I dont remember the tempratures) and then used within hours after they hit room temperature. Putting them on dry ice and as long as they are kept really cold they can be shot up to a couple of days later.

"Hence the nickname Icebox rivets."

I ain't that old, but many of my customers are, Leon Herman told me about those. You can read about them too but its more fun to listen to the old rivet beater's stories!

[David-aviator]

Originally Posted by ncarmon

After finishing my HS and VS 3 years ago, I'm back full steam. Something sticks in my head that I shouldn't use old rivets.

Do old rivets go bad?

Thanks.

Now that all the experts have spoken, it should be clear as mud whether old rivets go bad.

[az_gila]

Originally Posted by David-aviator

Now that all the experts have spoken, it should be clear as mud whether old rivets go bad.

It's sometimes easier to ignore the experts and read the actual Mil Spec....

MS20470AD rivets have no life time limits per the military specification...
If they really did go old (an old wives tale, IMHO......) the military would be concerned and the specification would require dating and a shelf life/storage temperature to be marked on all packages.... (NOTE - talking about our 426 and 470 rivets here...)

A copy of the spec. is here.....

http://www.av8design.com/Hardware/MS20470.pdf

UPDATE

http://www.tpub.com/content/aviation...3-0106_163.htm

This page of an Aerospace Technical Manual describes which rivets need differing temperature handling before use - our "AD" rivets do not....

This heat treatment site talks about the various alloys used in aircraft rivets, and the temperature requirements for differring alloys....

http://www.2nd-hardener.com/heat_rivet.htm

...with the key paragraph...

Alloy 2117 rivets have moderately high strength and are suitable for riveting aluminum alloy sheets. These rivets receive only one heat treatment, which is performed by the manufacturer, and are anodized after being heat treated. They require no further heat treatment before they are used. Alloy 2117 rivets retain their characteristics indefinitely after heat treatment and can be driven anytime. Rivets made of this alloy are the most widely used in aircraft construction.

I would contend that "diddling" with the heat treat of our rivets in an uncontrolled fashion could be dangerous unless each batch processed is checked for mechanical properties...



gil A

[WSBuilder]

FWIW, I just squeezed and bucked a bunch of left-over, 1983-vintage 426AD3-4's from my tail kit on my wing last week. Couldn't feel the slightest difference. I took a hand-held microscope to examine the shop heads and couldn't distinguish from the new rivets. I'll let you know if I shed my bottom wing skins in-flight, later.