Irvine's Weapons

Valiant
Needs: 1 Steel Pipe, 4 screws. The Steel Pipe is from a Wedingo in the Roswall Forest near Timber.

Ulysses
Needs: 1 Steel Pipe, 1 Bomb Fragment, 2 screws. See above for Steel Pipe, Bomb Fragment is from little red floating monsters called Bombs.

Bismark
Needs: 2 Steel Pipes, 4 Dynamo Stones, 8 screws. See above for Steel Pipes, the Dynamo Stones are from mugging high-level Creeps in Deling City's sewers.

Exeter
Needs: 2 Dino Bones, 1 Moon Stone, 2 Star Fragments, 18 Screws. The Dino Bones are from T-Rexaurs on Hell Island or Balamb Garden's Training Area. The Moon Stone is from mugging that weird black monster on Estar's highways. Star Fragments are from Iron Giants near Estar.