Hello everyone! I have made some charges to my boom, and was working on the cast aluminum portion. I used thickened epoxy to secure new fair leads and cam cleats, and it appears to be holding well.
I have done a fair bit of research on attaching things to thin aluminum masts and booms, and you realistically only have three choices: screws, rivets, or you drill through the mast and bolt from the other side (through-bolting).
The most secure method is through bolting, but obviously that creates a lot of holes in your mast. It really is toss up between the screws and rivets, but the deciding factor in my opinion is your level of experience. the problem with creating a screw hole is that aluminum is very soft, and you can strip the threads of you aren’t careful.
Blind pop rivets are very easy to use and are considered to be very secure as long as you pick the right size and material.
So after all that, I would suggest you go with a good quality rivet.