Blind Rivet Mandrel?

minuteman62-64

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Playing with 1/4" blind rivets. I understood there was an issue with the steel mandrels on aluminum rivets - part remaining in pulled rivet potentially causing rusting.

See attached photo of mandrel pulled from a 1/4" blind rivet. Isn't that the entire mandrel? How much would remain in the rivet body? I can't see anything remaining inside the rivet head.
 

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Frank Acampora

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Re: Blind Rivet Mandrel?

Typically "pop" rivets only leave a "ball" shaped piece inside the rivet body. In your case, with 1/4 inch diameter rivets, the ball would be about the size of a BB. In your photo, you can see the necked down portion of the mandrel which broke off the roughly ball shaped expanding head. Depending upon how well and exactly how the rivet expanded, it is possible for the broken piece of mandrel to simply fall out the back and you would not see it.

You need to be absolutely certain that you are buying rivets with aluminum mandrels. Do not buy cheap stuff (probably made in China) Try Graingers, Fastenal, (although a lot of their products are made in China) or Mc. Master-Carr. There are so many variations for specific applications that it is mind boggling. For example, there are flush rivets for aircraft use, rivets with a waterproofing seal, et cetera.
 
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minuteman62-64

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Re: Blind Rivet Mandrel?

Since my work will be above the water line I'll probably use regular (not blind) aluminum rivets with aluminum mandrels. I have not been able to find (including at Grainger's) blind aluminum rivets with aluminum mandrels - all seem to have steel mandrels.
 

smokeonthewater

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Re: Blind Rivet Mandrel?

all pop rivets are blind rivets... blind meaning they are installed from only one side... possibly you mean closed rivets where the business end of the mandrel is not visible from the back side of the rivet... closed rivets are important for boats because the standard rivets if used below the water line will leak through the center

Fastenall has closed rivets with stainless and aluminum mandrels... I have bought them there for boat work
 

jigngrub

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Re: Blind Rivet Mandrel?

Closed end blind rivets are used both in boat building and aircraft manufacturing, when set properly they create a water and vapor proof seal. They're a very strong rivet and not like the wimpy open end blind rivets.

If you're worried about rust from the little steel ball that remains behind you can seal the mandrel hole with a dab of 3M 5200.
 

minuteman62-64

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Re: Blind Rivet Mandrel?

Brain cramp. What I should have said is that I will probably use open end blind rivets for my above water line work. And, that Grainger didn't seem to carry closed end aluminum blind rivets with an aluminum mandrel.
 
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