Thorp Air Command - T18.net

I have old AN rivets of many sizes and lengths.

I recall WAY back many years ago reading in EAA Sport Aviation about annealing AN driven rivets.

I recall reading an article stating that the aluminum rivets both age and work harden. Driving the rivet work hardens them. Age also hardens them.

As a result old rivets that have been sitting on the shelf for years have age hardened. THe article stated that by pouring a bunch of rivets onto a cookie sheet and putting them in the oven will anneal them and make them soft and like new again.

The problem is two fold. One, I cannot seem to find that original article. (I have kept all sport aviation mas since about 1983). I also tried to do an online search now that all past issues are digital. Neither has resulted in finding the article.

The thing I'd like to know is what temperature to set the oven and for how long to let them "cook".

I realize that I can still drive and use the rivets "as is", but it will take more energy to set the rivet than if the rivet was new, or annealed.

If anyone knows the temp and length of time to anneal rivets that would be great. I'd rather use up what I have first. But am willing to buy new and keep my old stock for other projects.

The article stated that you don't have to worry too much about making them too soft. (obviously cannot melt them), as setting the rivet will work harden them, and typically it takes a few years for a person to build the airplane so that there is also plenty of time for the rivets to age harden while doing the canopy and installing the engine etc. And properly annealing them will get them back to if they were newly manufactured. So no harm no foul.

I just am trying to find out how to anneal them properly!

Thanks.

Initial anecdotal feedback suggests that the process to anneal are much more difficult and hot than can reasonably be done with a home kitchen oven.

Therefore I will plan to buy fresh rivets and use my old rivets for other non critical, non aviation related projects.

This subject has popped up dozens of times. The rivets you buy from Spruce are generally 2117 alloy. They can age harden. But I’ve had rivets that are over a decade old and drove them just fine.
You will definitely need to learn to remove a bad rivet if building a plane.
My advice, just use what you have.
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