Here I am riveting the pieces that make up the front spar of the horizontal stabilizer. I am using a hand squeezer to mechanically squeeze the rivets.

The front spar is made from four large pieces of aluminum riveted together.

The rivets can either be driven with an air powered rivet gun, or mechanically compressed (or "squeezed") with a hand (or air) powered squeezer. The squeezer can only reach rivets that are close to the edges of the material, so there are many places where the only choice is to use the rivet gun.

I get more consistent results using the squeezer, so I try and mechanically squeeze as many possible.