I messed up - attaching the leading edge on the left wing spar with pop rivets as Van support suggests. Though I used shorter rivets LP 4-3 instead of LP 4-4 - wasn't thinking about correct grip length the first time around.
After knocking out the mandrels and drilling out the short rivets, I did a bit of testing on scrap. Even with the LP 4 3 rivets in a .25 in. part - a small collar still formed and (barely) trapped the end of the mandrel. However, in most of the rivets I removed and the test pieces, only a very short piece of mandrel remains in the "shop side" of the rivet after setting. I thought the mandrel was supposed to break at the "manufactured head" side leaving the steel core to help bear shear loads?
Without the core - you only have a small aluminum tube taking the shear load on those leading edge ribs.
I hope the cherry max rivets I ordered will form a stronger joint than the LP rivets. If I had to use the LPs on those parts, I think I'd try intentionally bending the tool as I set them to make the stem break off at the surface of the rivet.
I have a few pictures of the tests on my facebook page if anyone is curious.
https://www.facebook.com/BZsRVproject/
After knocking out the mandrels and drilling out the short rivets, I did a bit of testing on scrap. Even with the LP 4 3 rivets in a .25 in. part - a small collar still formed and (barely) trapped the end of the mandrel. However, in most of the rivets I removed and the test pieces, only a very short piece of mandrel remains in the "shop side" of the rivet after setting. I thought the mandrel was supposed to break at the "manufactured head" side leaving the steel core to help bear shear loads?
Without the core - you only have a small aluminum tube taking the shear load on those leading edge ribs.
I hope the cherry max rivets I ordered will form a stronger joint than the LP rivets. If I had to use the LPs on those parts, I think I'd try intentionally bending the tool as I set them to make the stem break off at the surface of the rivet.
I have a few pictures of the tests on my facebook page if anyone is curious.
https://www.facebook.com/BZsRVproject/