Good question, Ants. I was not present nor privy to the boom repair technique, other than overhearing Buzz say the rivets were solid stainless steel. I did notice the rivet heads were countersunk slotted flathead and thus flush with the repair surface. After that, your guess is as good as mine. The sealant between the repair bandage and the boom was white 5200, which Buzz says is as good as any adhesive he knows.