# Rivets - removal, riveting, tools, etc



## tenuki (Feb 11, 2007)

I have some work to do on my boom and mast which will involve removing rivets and re-riveting, etc. I'm looking for advice.

1) How do I remove rivets safely and without messing the holes up?
2) What are your recommendations for rivet guns and rivets?

I have a Ranger 24 that I'm re-commissioning so it's not a huge boat with big loads or anything but I want to do it right. The first project is straightening out the boom control rigging stuff (vang, outhaul, reefing, etc) and I need to get the cap off to re-rig the outhaul. The second thing is taking out a sheeve box at the base of the mast and replacing the broken sheeve (6 riviets hold the current box in)

I searched the forums, but couldn't find advice on rivet removal.


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## DeepFrz (May 9, 2006)

You will have to drill the rivets out. Use a drill bit just slightly larger than the hole in the rivet. Pop rivet tools aren't very expensive. When you are finished riveting take a small pin punch and knock the center pin into the boom (hopefully you will be able to get them out of the boom after). Fill the hole with sealant (Sikaflex 291 or some such). You can use something like Duralac or Tef Gel to bed the rivets to prevent corrosion, although if you are using aluminum rivets there shouldn't be any problem.


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## poopdeckpappy (Jul 25, 2006)

Working on my boom also and I did the same as mentioned above.......a piece of cake


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## sailingdog (Mar 19, 2006)

Tenuki-

If you are going to do this, drill the rivets out as suggested... but go down to sears and buy their Craftsman heavy duty pop rivet tool, which is about $25 or so. It is one of the few manual pop-rivet tools that can handle stainless steel pop rivets up to 3/16" in diameter. 

If you're going to be drilling new holes for the new hardware, fill the old holes with thickened epoxy... and then sand it flush. If you're going to be using the old holes. Coat the rivets with tefGel, lanocote or some other galvanic isolation compound to help prevent corrosion between the stainless steel rivet and the aluminum mast. 

However, if the hardware is stainless steel, you should also use a thin sheet of plastic as a galvanic isolation washer, like the plastic from a plastic milk carton, which is low-density polyethylene. 

Finally, I don't recommend using aluminum rivets on a boat for several reasons. First, they are more likely to fail due to corrosion issues. Second, they are much, much weaker than stainless steel rivets of the same size. Third, they are also far more likely to fail due to deformation.


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## DeepFrz (May 9, 2006)

I agree with almost everything that sailingdog says 
*except* do not use plastic as a galvanic isolator.

instead use an adhesive sealant such as Sikaflex 291 or 3M 4200 (not 5200).

If you are riveting high stress items use stainless or Monel rivets and set them in Duralac.


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## stevemac00 (Feb 16, 2007)

Is your mast/boom painted? I'm not sure how long the epoxy will last if it's not painted.

In my opinion Dog's pretty much got it right. I'm removing a behind the mast furler with a lot of rivets. The thing I'd clarify is you don't want a stalactite of epoxy hanging inside. Use a countersink to slightly countersink the holes as a base for the epoxy. You can get aluminum "putty" (epoxy) from McMaster but it's expensive. I'm using standard West 105 but adding sufficient filler to be thick. Use 420 aluminum filler (WEST SYSTEM Epoxy) which has some UV protection and is base for paint.


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## sailak (Apr 15, 2007)

Hi guys. New here on the forum, learning a lot!! Hope to own a boat soon.

Why fill the old rivet holes? Is it aesthetics? or a structural thing?

Thanks.

Dale


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## sailingdog (Mar 19, 2006)

DeepFrz-

The boat is a Ranger 24... I don't see any of the loads being all that high on it ever... it just ain't that big a boat. 

Sailak-

You want to fill the holes to reduce the amount of water getting into the mast. Also, the holes will have rather sharp edges and can chafe lines or skin that rubs against them....which doesn't happen if they're filled and sanded flush.


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## tenuki (Feb 11, 2007)

So on stainless vs aluminum rivets, it sounds like here are the pros/cons

aluminum - pro: easier to rivet, no galvanic corrosion, easier to drill out
cons: less shear and tensile strength

stainless - pro: better sheer and tensile strength
cons: hard to rivet, galvanic corrosion, [edited] hard not impossible[/edited] to drill out

Seems like I should be able to find aluminum rivets that are strong enough for my little R24? Stainless seems to have so many disadvantages over aluminum that I'm shy of it. It looks to my inexperienced eye like the factory rivets are all aluminum (but I haven't tried drilling em yet either).


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## tenuki (Feb 11, 2007)

further research show the following info (please note this is general and out of context info, not a engineering study or anything)

Looks like for 3/16 rivets (varies greatly with brand):

Aluminum - ~300 shear, ~500 tensile
Stainless - ~780 shear, ~1040 tensile

So stainless is clearly over twice as strong. Now I'm wishing I had my good ol' strain gage from my engineering materials class for my next sailing session.  Anyone know the size of forces generated on say a out haul block on a 24' sailboat?


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## txmatt (Nov 27, 2006)

tenuki said:


> So on stainless vs aluminum rivets, it sounds like here are the pros/cons
> 
> aluminum - pro: easier to rivet, no galvanic corrosion, easier to drill out
> cons: less shear and tensile strength
> ...


You should be able to drill out stainless rivets.


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## tenuki (Feb 11, 2007)

why not just pop in an aluminum rivet to cover old holes instead of epoxy?


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## sailingdog (Mar 19, 2006)

Tenuki-

Pop rivets have a tiny hole in the center, where the mandrel is located... not water tight. Also, do you want your boat to look like a junkyard reject... and it adds windage and weight aloft.


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## poopdeckpappy (Jul 25, 2006)

IMO, anything that going to take a stress would be drilled, tapped and screwed and there really should be that many items, everything else could be rivited with aluma, alou min, a-lou - me, ah f**k it, not stainless


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## tenuki (Feb 11, 2007)

sailingdog said:


> Tenuki-
> Also, do you want your boat to look like a junkyard reject...


Yes I do, it's my cheap ass security system..


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## sailingdog (Mar 19, 2006)

PDP-

In many cases, rivets are actually stronger than the screws would be, when connecting hardware to a mast. Most of the times the only threaded surface bearing the loads for a machine screw that is attached to a spar are the four-or-five courses of threads in the wall of the spar itself...which isn't all that thick. A rivet is held in place by the peened over section that the mandrel mushrooms out... and that, plus the fact that the diameter of the end of the rivet is larger than the hole generally give it a good deal of support. The main reason to use screws over rivets when adding hardware to a spar is if the hardware needs to be easily removed for servicing or replacement. 

For instance, I used 3/16" stainless steel rivets to attach several small padeyes to the spreaders on my boat.... I don't see any need to remove them or repair them...there's really nothing on a padeye to break or service. For the line clutches and winches, I used screws. However, I would bet that the two SS 3/16" rivets would support as much weight as the five or six screws used to hold the winch to the mast.


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## tenuki (Feb 11, 2007)

Ok, I'm knee deep in this project now, things going ok. One question:

The previous owner apparently liked stainless steel 'sheet metal' self tapping screws. They seem pretty good actually, I've removed a bunch of them to exchange out some sheeves and I think I'm gonna go this route for the main mast shaft instead of rivits unless it's something I'm not gonna move ever. btw, the old rivets were aluminum, so I'm guessing that would be ok to use for most of my stuff too. The aluminum rivets drill out so easy I'm temped to use them for everything to cut down on galvanic corrosion....

The mast head is pretty thick aluminum, so anything I got to put on there (antenna) I'm gonna drill, tap, and use ss screws. btw, I saw this on another forum, anyone ever use

Rivet Nuts and Threaded Inserts, avk nuts, ribbed L rivets nuts, ribbed K rivet nuts, half hex rivet nut, flat head rivet nuts - Jay-cee Sales & Rivet Inc.










there is something similar sold under brand name RivNut


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## sailingdog (Mar 19, 2006)

I'm not a big fan of self-tapping screws, especially for use in aluminum spars, since the threads aren't as strongly formed as those made with a proper tap, and the material is relatively thin to start with...so each thread has much more affect on the grip of the fastener. 

The Rivet Nuts look like a pretty good solution. It looks like the stainless steel ones are custom order and may have a fairly high minimum number to order. I am curious as to how much the tools and fasteners cost.


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## Boasun (Feb 10, 2007)

tenuki said:


> Ok, I'm knee deep in this project now, things going ok. One question:
> 
> The previous owner apparently liked stainless steel 'sheet metal' self tapping screws. They seem pretty good actually, I've removed a bunch of them to exchange out some sheeves and I think I'm gonna go this route for the main mast shaft instead of rivits unless it's something I'm not gonna move ever. btw, the old rivets were aluminum, so I'm guessing that would be ok to use for most of my stuff too. The aluminum rivets drill out so easy I'm temped to use them for everything to cut down on galvanic corrosion....
> 
> ...


This looks good. But do need a surveyor or N.A. report on them. Or someone who has field tested them on their own boat.
The mast manufacturer's feelings about them?? Some one!?


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