Which type of metal for Rivet Nuts?

[Danglerb]

I read the thread on rivet nuts and decided it might be handy to have some for some unknown general use, but which type of metal should I get the rivet nuts in, aluminum, steel, or stainless?

Cheap kits of half a dozen sizes are $8 to $15 on ebay.

 

[Superbec]

get alum and steel first , stainless will require a better/good gun and it's application specific .

 

[95riosnake]

I have used a few for various things, I personally went with the steel ones for strength, and the application wasn't really prone to rust. Really the material choice is purely dependent on what you think you might be using them for. Outdoor/wet use with high strength would call for stainless, limited exposure with high strength would call for steel, and light duty indoor or outdoor would call for aluminum.

 

[95riosnake]

Superbec is right about the stainless, it will take a lot more effort to properly install the stainless due to how hard the material is. Even my steel ones were a bit rough to install when using the larger sizes. I actually broke one of the threaded tool tips installing one and had to order a replacement.

 

[PelicanPines]

I have all three... BUT... I only get Stainless for a needed task. Alum and Steel... I have an assortment.

I match the Riv/nuts to the metal i'm using them with...

I do the exact same thing with pop-rivets... however... I keep an assortment of stainless for those as well.

I wish I had an air powered riv nut gun... <-- if santa is listening.

 

[Danglerb]

I think I will start with aluminum, easiest, then move up depending on need.

 

[pop pop]

What would you use on galvanized? I have one that needs replacement as it is loose and turns with the bolt on my trailer.

 

[rlitman]

Aluminum is the easiest to squeeze, but the threads are the weakest.

But there's more to rivnuts than just the material type.
They're application specific, and different ones work better in different thicknesses of materials. If you're dealing with thick stuff, the standard type that mushrooms the back and pulls it forward like a typical pop-rivet is fine. In sheet metal, those don't hold as well as ones that "hole fill" by expanding outwards. The hole fill type has a cone in the back that breaks off, and pulls into a mating recess in the front. One example of this is the A-T type:

This image highlights the rear conical section that breaks off:

 

[DHCrocks]

I've had the type that breaks off to fill the hole as you say fail on me several times. The threaded portion that breaks off sometimes falls out the back of the hole when you remove the bolt.

I prefer the type that mushrooms and is a soild one piece.