Wednesday, November 26, 2014

Obscure Fasteners -- Exploding Rivets

When I was a boy, my dad's basement workshop had in it a big soldering iron. My dad told me that it was for installing exploding rivets. I don't recall him ever having given me a demonstration.

Anyway, he left me a small supply of the rivets.

(Those are 3/16" diameter x 3/8" long truss head rivets.)

Those are not what passes for 'exploding' rivets today -- hollow rivets that peel back broadly as they're clinched. The rivets pictured above have an actual explosive charge inside them. When the head of one of those rivets is heated by a soldering iron, the charge goes off and swells the rivet's shank, clinching the rivet. Here's a demonstration.

I scrounged up two aluminum brackets that already have 3/16" holes in them, and arranged them in the vise with a rivet in place.

It takes but a few seconds for the rivet to go off once a hot soldering iron is pressed against its head. There's quite a BANG, the explosive charge blows out the end of the rivet and swells the rivet's shank, like so.

The resulting join is quite secure.

I've googled 'exploding rivets', and all I come up with is the hollow peeling/folding types. These are way more fun, but some prissy safety agency probably outlawed them long ago. I'll have to make judicious use of the small supply that I have.

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  1. The rivets went off the market in 1971. Apparently they were used to assemble Airstream trailers... that would be quite a sight (and sound).

    1. Thanks for the additional information.

      I think it's a shame that the rivets are no longer available -- they're the neatest 'blind' fastener I've ever seen.

      As for safety, they're no more dangerous than Ramset fasteners, and those are still around. It's not as if the rivets hurl shrapnel; they don't. So long as one stays clear of the rivet's discharge path, there's no danger from them.