What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Oblong Holes - Fuel Tanks & Proseal

skelrad

Well Known Member
Friend
It's become apparent that the first tank I ever drilled to final size was a less than stellar showing of skill. I figured it out on the second tank, but this first one was definitely in the learning curve of "how in the world are you supposed to get ribs to fit in the skins?!?!" I actually sealed my second tank first, so now am starting on this learning curve tank. As I'm dimpling skins, it is very apparent that some of these ribs were under a lot of tension when clecoed in, and I drilled oblong holes in a lot of places.

How do you decide when a hole is just too big and needs to be upsized for an oops rivet? I guess the question is how much do rivets expand to fill a hole (maybe using a slightly longer rivet)? I'm not super worried about anything from a structural standpoint - each rib does have a hole here or there that needs to be addressed, but given how hard it is to pull apart prosealed metal, I'm guessing that even shoddy rivet work on a tank is not really a problem (assuming sealing is done well of course).
 
Last edited:
Mil-Spec

It's become apparent that the first tank I ever drilled to final size was a less than stellar showing of skill. I figured it out on the second tank, but this first one was definitely in the learning curve of "how in the world are you supposed to get ribs to fit in the skins?!?!" I actually sealed my second tank first, so now am starting on this learning curve tank. As I'm dimpling skins, it is very apparent that some of these ribs were under a lot of tension when clecoed in, and I drilled oblong holes in a lot of places.

How do you decide when a hole is just too big and needs to be upsized for an oops rivet? I guess the question is how much do rivets expand to fill a hole (maybe using a slightly longer rivet)? I'm not super worried about anything from a structural standpoint - each rib does have a hole here or there that needs to be addressed, but given how hard it is to pull apart prosealed metal, I'm guessing that even shoddy rivet work on a tank is not really a problem (assuming sealing is done well of course).

Technically, Mil-Spec 43-13 would be the definitive guide. Officially, measure and refer to the tables in the document. If the hole exceeds max, drill and use the next size up assuming edge distance compliance.
Unofficially, a rivet will expand to fill. Yes, longer rivet because more aluminum is utilized expanding into the space.
 
Back
Top