Built jig do re-prep / re assemble flap brackets. Using Alodine prep pen to touch up reamed out holes. Aluminum bits between layers and some deburring needed. Attempting to back rivet by holding rivet bit up in a wood block and using back rivet bit to flatten shop end. Note: had to drill small hole on opposite side of 4x4 to be able to punch out the rivet set. Rivet gun had set it in nice and snug.
