Riveting question

[Pagan Baby]

I‘ve been doing some riveting on my mast with monel 4.8mm rivits. Most of the time the rivit sets well, I get the “pop” as the bead breaks off and everything's fine. Occasionally I don’t get the “pop” and the mandrel slides through the rivit and into the mast. The first time it occurred I drilled out the rivit and it was firmly anchored. I tried recreating the no-pop riveting in the garage with two similar thicknesses of aluminum but every time got the “pop”.

any thoughts about what’s going on? Should I drill out the ones that didn’t pop and try again? They seem to be set.
Thanks in advance,
Tom

 

[RitSim]

I had the same issue. I'm interested in what others say. In my case, I felt the rivet deforming and the rivet stem just broke in a different area. I cut the stem and filed it smooth

 

[Tedd]

I've done a lot of riveting over the years, having been involved in a few airplane projects and having built quite a few wings and similar parts for racing cars. In my experience, when a rivet fails to set in the way you've described it's usually one of two things. The first is simply poor quality rivets, which includes most rivets you get at a hardware store. The second is an inadvertent twisting or prying motion applied to the rivet gun while squeezing. That's easy to do when riveting in an awkward position, which is one reason this problem is hard to reproduce when you're working in the shop. When you can hold the rivet gun in a comfortable position while you squeeze, it's relatively easy to squeeze without applying any twisting or prying force at the rivet. But that gets much harder when you rivet in situ, where you may have to bend over, or reach, or in some other way hold the rivet gun awkwardly.

 

[Pagan Baby]

Tedd, You’re a genius! Thanks so much for your feedback. After reading your post I had a hunch that twisting the rivet was the problem and sure enough after removing the affecting rivets and taking care not to twist the rivet gun when taking a second bite they all set beautifully with a resounding “pop”. If you ever find yourself in the upper Chesapeake I’ll buy you many beers!
Tom

 

[Tedd]

If you ever find yourself in the upper Chesapeake I’ll buy you many beers!
Tom

That's almost a good enough offer to make the trip. But I'm 'way on the opposite side of the continent so it probably won't happen any time soon! Glad it helped.

Tedd

 

[jssailem]

Great write up @Tedd.

If the border ever opens and you need to get out and stretch your legs the Upper Chesapeake is a pretty area to visit. They have tasty soft shell crabs, fun sailing waters and you may find a beer worthy.

All of that will be distinctively different from the BC waters on the Pacific NW.

But it was several beers.