Strength of rivets

rogerwa · Jun 13, 2012

I have to decide between using pop rivets for an application or using sheet metal screws. I am attaching a thin aluminum plate to the fence rails of my pontoon to mount my ob controls.

Would the rivets hold tight over time or would sheet metal screws be a better choice. I also worry about those backing put as well.

Thanks..

Bondo · Jun 14, 2012

Re: Strength of rivets

rogerwa said:
I have to decide between using pop rivets for an application or using sheet metal screws. I am attaching a thin aluminum plate to the fence rails of my pontoon to mount my ob controls.

Would the rivets hold tight over time or would sheet metal screws be a better choice. I also worry about those backing put as well.

Thanks..

Ayuh,... Screws will loosen, Long before rivets will...

Bob_VT · Jun 14, 2012

Re: Strength of rivets

Rivets themselves are stronger then the aluminum they will be going through and much ore "bearing" area since they create a flange on both sides. Sheet metal screws are only "flanged" at the head and the only grip is from the threads making one bite into the aluminum.

If you lightly sand the aluminum and apply a lisght layer of 3m5200 between the pieces before you rivet it will be stronger and water proof. You also could use a two part epoxy but my choice is 3m5200 which is strong (about 400 PSI applied to aluminum).

Tim Frank · Jun 14, 2012

Re: Strength of rivets

Why not use "right-length" bolts that go right through the rail, and finish with acorn nuts for aesthetics?
Then you have no worries.

Georgesalmon · Jun 14, 2012

Re: Strength of rivets

Use bolts and nylock nuts, SS of course. Blind rivets will loosen in time and then must be replaced, you can't tighten them up. Even with screws that may loosen sooner than rivets you can tighten them up easily.

bruceb58 · Jun 14, 2012

Re: Strength of rivets

If you do decide on rivets, make sure you use stainless steel ones. I would prefer screws/nuts myself.

mscher · Jun 14, 2012

Re: Strength of rivets

bruceb58 said:
If you do decide on rivets, make sure you use stainless steel ones. I would prefer screws/nuts myself.

Isn't direct contact, between dissimilar metals, usually a recipe for possible galvanic corrsion?

http://www.ajaxfast.com.au/downloads/AjaxRivetsHandbook.pdf

jigngrub · Jun 14, 2012

Re: Strength of rivets

Use rivets, but use the closed end aluminum blind rivets. They're much stronger than the open end and will last much longer. they do cost more than the open end rivets, but are still much cheaper than SS screws.

bruceb58 · Jun 14, 2012

Re: Strength of rivets

mscher said:
Isn't direct contact, between dissimilar metals, usually a recipe for possible galvanic corrsion?

You mean like every stainless steel bolt that is threaded into our aluminum sterndrives?

According to your link, stainless steel attaching aluminum is ok in mild environments which I would think Minnesota would be where the OP is from.

mscher · Jun 14, 2012

Re: Strength of rivets

bruceb58 said:
You mean like every stainless steel bolt that is threaded into our aluminum sterndrives?

According to your link, stainless steel attaching aluminum is ok in mild environments which I would think Minnesota would be where the OP is from.

Good question and you are probably already aware of the corrsion potential of this setup.

I don't have the exact answer, but I'd guess, that since AL does not make for very strong bolt and nuts, SS was likely the next best option, even if it not the perfect option. Pop rivets might be a whole other story.

The strenght differencee between SS and AL pop rivet may not warrant, the chance of additional corrosion, even in fresh water marine environment, due to the dissimilar metals and the thin, possible flexing material being fastened.

Then again, they may work just fine.

bruceb58 · Jun 14, 2012

Re: Strength of rivets

I have aluminum plates in my engine compartment held on with stainless steel nuts and bolts. I see no appreciable corrosion and I boat in salt water.

There are a lot of aluminum trailers out there held together with stainless bolts! They get dunked in salt water!

Aluminum pop rivets are just not very strong and using them to mount anything with any kind of vibration is asking for a failure.

rogerwa · Jun 14, 2012

Re: Strength of rivets

Thanks for opinions.. My main interest is not having to go all the way through the rail. I was planning on using the ss rivets with a good sized head on it. When I looked at the boat at the factory, large headed rivets are what they used so it should be ok.

foodfisher · Jun 14, 2012

Re: Strength of rivets

That was kind of like waiting for the hiss when the sun hit the horizon.

jigngrub · Jun 15, 2012

Re: Strength of rivets

rogerwa said:
Thanks for opinions.. My main interest is not having to go all the way through the rail. I was planning on using the ss rivets with a good sized head on it. When I looked at the boat at the factory, large headed rivets are what they used so it should be ok.

Here's a good source for the rivets you want if you don't already have some place in mind to get them:

http://www.rivetsonline.com/stainless-steel-stainless-steel-mandrel-w-large-flange-head.html

Strength of rivets

Commander

Moderator

Moderator & Unofficial iBoats Historian

Vice Admiral

Lieutenant Commander

Supreme Mariner

Lieutenant

Fleet Admiral

Supreme Mariner

Lieutenant

Supreme Mariner

Commander

Captain

Fleet Admiral