Aluminum Rivet Installation

[John A.]

Hi Everyone!!!

I posted a question a few weeks ago about how to mount the steel plates under the body using the soft aluminum rivets that came with the parts. I remember someone telling me to have someone up above hold something like a sledgehammer on top of the rivet head while I use an impact wrench to flatten the end of the rivet from below. He said to make a tool for the impact wrench having a shallow 1/4" hole in the end and use this to flatten the rivet. Not knowing too much about how an impact wrench works, I am wondering 1) would this approach give good results and 2) if so, is there a certain type of impact wrench(i.e. quality, power rating, etc.) that should be used? I need to get this operation done soon since my seats will be coming back from the restoration shop soon and I want to get them in.

[John H.]

Re: Aluminum Rivet Installation

John -

You don't want an impact wrench, you want an air hammer that accepts the usual .401" shank tools. I use an ordinary Ingersoll-Rand air hammer with a mini-regulator at the inlet - you only need 10-15 psi for aluminum riveting. Aircraft Tool Supply has a great selection of 3/16" rivet set tools with .401" shanks.

[John A.]

Re: Aluminum Rivet Installation

Thanks, John. That's just what I needed to know. So, I take it, the requirement that someone be above with a weight on the rivet head still holds? I would think that would be necessary but just checking.

[Greg L.]

Re: Aluminum Rivet Installation

John A, The weight(bucking bar) to "back up" the head of the rivet is very important otherwise you will just push the rivet back through the hole when you start to hit the tail. These are what you call soft rivets so they are easy to install and a weight of a pound or two is good enough if you have some one to hold it for you. Make sure it is flat against the rivet head and hold it with a firm and steady force because the rivet gun will try to knock the weight off when you pull the trigger. Also if the rivet head will be exposed afterwards you want to make sure that your bucking bar is smooth because any marks on the bar WILL be transfered to the rivet head during the bucking process.

If you have never used a rivet gun before they can be a little difficult to control so you might want to practice on something else first. A good way to set up the trigger (how hard and fast the gun operates) is to hold the gun with it's tool piece(called a snap) against a block of wood on the floor and pull the trigger. I think that with these soft rivets that having the air control at the gun turned way down would be the way down to go.

To be honest I never needed a rivet gun for my car. I just made about a 1/4 or 5/16 concave depression in a 3/8 x 6" bolt and hit that with about a 2 lb hammer. The problem that I saw with these rivets and the body holes is that the rivets fit very loose in the holes. To buck the rivet properly so that it holds, it should have a tight fit between the rivet shank and the hole otherwise they tend to bend over to the side much like a nail. Even though I didn't use a rivet gun it was still a challenge with some rivets to get them to buck properly. You hit it once and then if the rivet is going off you readjust the angle that you last hit it on to try and keep it filling the hole and compressing evenly rather than just partially filling the hole and bending over to one side.

One thing to be aware of too is how much the tail sticks out through the hole. Standard practice is that the tail should protrude out of the hole 1-1/2 times the diameter of the shank so a 1/8 dia shank should be sticking out about 3/16". This is assuming that the shank and hole are a good fit which like I mentioned often are not on these cars. This is where you may need to experiment a bit depending on how poor the hole fitment is. I found that with 1/8" shanks in most cases if I had a 1/4" or so of the tail sticking out of the hole it would be okay but some really loose holes needed a bit more. The nice thing about these rivets is that once you are finished installing one and if you don't like how it looks, it is easy to drill out and start over.

I hope this helps a bit.

[Dale O.]

Re: Aluminum Rivet Installation

John,
I've been putting in a number of these 3/16 rivets while restoring my 65 and I use an air hammer as John discribed. However, I bought a bucking tool from LIC that works very well. The rivet is hammered from the head end and the bucking tool is used on the tail of the rivet. The bucking tool has a concave area to mushroom the rivet. This keeps the head against the item you fastening and also compresses the componets together and expands the rivet shaft for a snug fit. One other thing, I cut the shaft for the air hammer so it was only about 2" long and ground it flat so it would not damage the head of the rivets. The short shaft makes it easier to control. Also, as John said turn down the air pressure. You may want to check the archives, too. Good Luck!

[Greg L.]

Re: Aluminum Rivet Installation

Well I stand corrected then because I was told to place the bar against the head and hit the tail so that was how I did it.

I know that standard riveting practices(in aviation anyways) is to do as you say Dale and hit the head instead of the tail and I remember thinking that it was odd to do it the way I was told because it seemed backwards....

At any rate either way seems to work but knowing me I did it the hard way!

[John A.]

Re: Aluminum Rivet Installation

Greg and Dale,

Thanks for the very good information. It doesn't seem like a difficult operation but, not having done it before, it helps to talk with those who have been there and done it. I think I will buy the IR air hammer pictured in Greg's reply and use a short tip as Dale suggested. The short tip should work better whether I do it from above or below. I can see where a tip with a flat surface would be good for hitting the rivet head from above. I'm not sure whether I can buy a tip with a concave end to do the job from below.....but I could drill a 1/4" hole in the end of that tip. I see where Aircraft Tool Supply has rivet sets with various openings(1/8,3/16,1/4" etc.) with 0.401" shanks. The one listed as 3/16"x3" long with 10 degree offset seems like the one that would work best. Correct me if I'm wrong. I would like to find a mini-regulator like Greg's. Haven't found one on line that looks like his yet but I will keep looking.

[John A.]

Re: Aluminum Rivet Installation

Dale,

I would like to get the bucking bar you talked about in your reply. What does LIC stand for?

[Greg L.]

Re: Aluminum Rivet Installation

Dale,

I would like to get the bucking bar you talked about in your reply. What does LIC stand for?

LIC= Long Island Corvette.

http://www.licorvette.com/

[Dale O.]

Re: Aluminum Rivet Installation

John,

The LIC part number is 55-2A for the 3/16 rivets. The web site Greg listed has a catalogue in pdf format you can down load. Look in Section # 55.

Greg,

This board is so great, we can exchange ideas and methods and find something that works. A couple of years ago I would never have thought about using the air hammer if Hinckley had not posted his photo back then.