Aluminum Mast Repair ?

[leslie]

I have a 1" hole in my mast below the gooseneck area. Found it while chipping off paint bubbles. I am in the middle of no where. No Mast manufactures or ship yard. There is a workshop that can weld aluminium but not sure if it will just create another weak spot. Should I make doubler plates with rivets or have it welded?

[Rearsteer]

Your idea of a doubler plate with rivets is the way to go. Aircraft are put together with plates and rivets. Then when you get to a yard you can have it checked out. Keep your mast loads light in tell its checked out.

[roverhi]

What caused the hole?? Is it corrosion or an old fitting that was removed and puttied over?? If the latter, wouldn't worry about it, if the former it might require further remediation to cure the cause of the electrolysis and reinforce around the hole. In and of itself, a 1" puka is not a big deal in the strength of the mast. Racing boats cut a bunch of slots in the mast to run internal halyards without a problem. Our mast has had a lot of hardware added and removed over the years and the mast is still functioning well. If you think the mast needs reinforcement, riveting a piece over the puka is the conventional way to repair aluminum. Look at long time service/high flight hour 737s if you want to get an idea what Boeing and the FAA think of how strong these type of patches are. FWIW, aluminum welds about 25% weaker than the surrounding metal. That is unlike steel welding where the welds are just as strong as the metal being welded.

[barnakiel]

Depending on the size. Small hole forget it and go (you can actually drill it to a fine round shape). Big hole - plate and rivets.

Now, the real question is - is this the only hole and how did it happen to be there?

b.