Fittings on a carbon mast of a high performance catamaran (18ft Whisper) are coming loose and need new rivets. It's all 3/16, small rivets.

Googling around, I can find stainless steel pop rivets, or I can get aluminium tri-fold rivets. I've tried both; with limited success. I want -- and the mfg in the UK recommends -- tri-fold SS rivets. Does anyone know where I could find them? Hopefully order online in the USA.

Help!?

I had not heard of tri-fold rivets, but the aluminum version looks like a great solution to the rivets on my tramp that are pulling loose at the rear. The exploding head or trifold design would be like adding a washer and distribute the load into the glass. This would be a lot easier than pulling the deck to reinforce a conventional rivet.

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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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If your rivets are loose already, are you sure the manufacture is the most qualified to provide the best advice? Plenty of boats much older than your's do not suffer these issues. Its true that there are far superior rivets to the ones mostly see on beach cats, but the reason is that they are not necessary

There are monel/ss rivets here.

http://rivetsinstock.bmob…b-tite-blind-rivets.html



Edited by bacho on Apr 19, 2017 - 11:01 PM.

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Greenville SC

Offering sails and other go fast parts for A-class catamarans
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That Bulb Tite rivet is interesting for its load sharing back. Curious to know what the special tool is. Is it just a special nose for a standard rivet tool or something more? I would also want to know about shear strength compared to SS and Monel rivets. Many of the rivets on a mast are in high shear applications, so it would be important to know the differences before committing. For sure we know that standard aluminum rivets are not up to many of the applications in a mast.

I think Tom is on to something for using these folding rivets in tramp tracks.

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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For the tramp I ended up buying aDP Exploding Pop Rivets ABS610XPeel. These are a longer 3/16 diameter aluminum rivet that uses the nail to cut a curling peel from the end of the rivet body, resulting in 4 strong curls that support the rivet against the inner surface. These are supposed to have a 1000 lb holding strength, and will fill over-size holes like my worn fiberglass has. It is a very strong attachment and the main disadvantage is the rivet leaves a sharp edge on the blind side. Not a problem for the boat, but could be an issue in body work and other applications.

Quote

ABS610Expeel Exploding Rivets made in USA
ABS610Expeel exploding rivets have a few unique advantages over other types of tri-fold or peel rivets.
These ABS610EXpeel Exploding Rivets in Silver/Mill finish: Extra, extra Long length for gripping 1/8″ to 9/16″ thick application materials. Aluminum 3/16″ rivet body diameter with 3/8″ head size and 7/8″ long shank. Assembled with enhanced design special steel nail with 1,000 pounds pulling power for outstanding clamping action on your application. Take a look at the Advantages when using our ABS610Expeel exploding rivets.
1. Works in over-sized, oblong and worn out holes up to 1/4″
2. Tight clamp-up and holding power, from 1/8″ to 9/16″ with 1,000 pounds clamping power.
3. NO back-up washer needed. The banana type peeling action will clamp without needing a back up washer.
4. These rivets will work with any functioning blind rivet setting tool.
5. The unique peeling action pulls multiple layers of application together from the extreme back end of the rivet. Unlike other “exploding” rivets which only pull from the middle of the rivets length and often don’t clamp multiple sheets tight.
Recommended application conditions for our ABS610Expeel exploding rivets: Start with Drill size 7/32″ for 0.213 to 0.220 hole diameter. The application thickness before the rivet is inserted should be between 1/8″ to 9/16″. This will allow our 3/16″ diameter high alloy Aluminum rivet body with 3/8″ dome head size and steel nail to perform as intended.
These ABS610Expeel exploding rivets are often used in applications where the holes have either become oval or just too big for standard 3/16″ diameter rivets. When the tool pulls the mandrel or nail, the head of the nail begins spliting, then pedaling back the rivet body just like you would commonly peel a banana. While the four pedals peel, they spread out and pull down the backside materials to form a tight, pulled together application that won’t come loose too easily due to the 1000 pulling power of this rivet’s nail. Good selection for fastening fiberglass, sheet metal and many other materials.

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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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Peel / exploding rivets just "unpeel" under pressure when pulled. Not my fave.

The folding/trifold/monel style rivets fold right against the surface, increasing the contact surface... so they work much better with carbon/fiberglass, etc. In a sense they form their own washer. For affixing things to carbon spars, where the fasteners will be pulled -- I wouldn't use peel rivets.

For the trampoline -- which I don't know your boat but seems likely that _shear_ loads on the rivets will dominate -- it's probably ok.

I'll let you know if I get wet. Seemed perfect for the tramp application. FWIW, the force it would take to "unpeel" one of these rivets is far beyond any original load design anticipation. They would first crush,and that would be well beyond any load anticipated for a conventional rivet.



Edited by tominpa on Apr 21, 2017 - 11:09 PM.

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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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tominpa

I'll let you know if I get wet.

Speaking of wet, those rivets have an "easy out nail" feature to make drilling out later easy. However, this means you will have to inspect them often to see if you need to seal them against water leaks.
Personally, I dislike adding more work to my boat.
My $0.02

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Sheet In!
Bob
_/)_____/)_/)____/)____/)_____/)/)__________/)__
Prindle 18-2 #244 "Wakizashi"
Prindle 16 #3690 "Pegasus" Sold (sigh)
AZ Multihull Fleet 42 member
(Way) Past Commodore of Prindle Fleet 14
Arizona, USA
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When the rivets pull, they leave a hole in the center. The nail that cuts the rivet body falls right out. So some clear acrylic caulk plug will solve any water issues quickly and permanently. The rivet head is very strong, and the way the back curls and rests against the blind side is extremely strong.

With regard to more work, the alternative is cutting access or removing decks. I could tell you which is more work, but I think you can guess.

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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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