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-   -   aluminum or stainless rivets? (http://www.sailnet.com/forums/sailnet-faq/68396-aluminum-stainless-rivets.html)

caver504 09-19-2010 12:05 PM

aluminum or stainless rivets?
 
I need to replace the rivets that hold the spreaders on, pulleys, and metal lines going to the deck (I don't know there name). I've searched the forums and people seem to disagree about stainless vrs. aluminum

The boat is a 16 foot sunbird. I would guess it would get the same stress as a flying scott.

the originals seem to be aluminum in that they are breaking. I really don't want to mess with coating the stainless steel.

But will the aluminum be strong enough? Is there a recommended strength rating?

Also, there is one metal line going from the mast to the aft area. I guess this hooks into the boom? That's what it looks like in old pictures.

hellosailor 09-20-2010 06:30 PM

"Also, there is one metal line going from the mast to the aft area. I guess this hooks into the boom?"
That sounds like a topping lift. If you're not sure what the rigging correctly is--try to find other sunbird owners and make sure it is right.
Generally you don't want to mix metals and the question would be whether the originals are breaking because ? old age? Does it take 20 years for them to fail? Do other owners say they are a design error? Or maybe, someone just didn't set them properly.
There are all sorts of "pop" rivets and riveting tools, I'd suggest looking over some and contacting the manufacturers to make sure you are using one with the necessary quality. The chandleries, Grainger, McMaster, Jamestown Distributors, all should have a couple for you to choose from. It could be the pop rivets that were used were simply cheap, and moving up one size would give you the extra strength you're looking for. Or, a different brand may be all you need.

nickmerc 09-20-2010 06:55 PM

If you are worried about the strength of aluminum rivets, just think about the load directions they will see. If you are just holding spreaders into place so they do not fall off when not under load aluminum will be just fine. Another example is holding a cast aluminum cover on the end of the boom.

If the rivets will see substantial sheer forces, then you want to think about stainless or monel. Monel does not react with aluminum so you do not have to worry about isolating the rivets. If you use stainless or monel, I suggest getting a pneumatic pop (blind) rivet gun. It will seat the rivets much better than a hand powered one and they are not too expensive.

Monel rivets are expensive unless you buy them by the thousands. So, expect to pay around $0.50 for each rivet.
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GLASS PIPES

rgscpat 09-21-2010 07:39 PM

Yep, Sail Texas had a couple of pictures of AMF Sunbirds where you could see the topping lift going from the masthead to the aft end of the boom.

caver504 10-06-2010 05:40 PM

thanks
 
I've put in stainless rivets. The hardware is stainless and the mast is aluminum. I put some lock-tight on the rivets to help stop the oxidation. Not sure where the oxidation was going on before. Seemed like it was just very old.

A new problem is pulling the rivets. pneumatic puller that are reasonably priced can only do aluminum and up to 90 pounds. These take a ton more force. I would guess around 300 pounds or so to have it pop. I used a carpenters clamp to help provide the power. I've also used a large table vice that is not mounted on the table. Really slow process. I may have bent the puller in the process. Can't seem to get good purchase on the rivet. I squeeze it down and it doesn't make any progress.

My other problem is figuring out how to mount oarlocks. I don't have money for motor right now and I want to row it anyway. I've never worked with fiberglass. Is it possible to drill it without cracks? Is it possible to cut?

nickmerc 10-07-2010 07:35 AM

What size rivets did you use? I had no issues with an affordable pneumatic pop-rivet gun for stainless on my Hobie 16 and 18. It was at the upper limit of the tools capabilities, but it worked fine. At least they are in there.
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How To Roll A Blunt

caver504 10-07-2010 03:34 PM

thanks for responding nickmerc. The rivets are 3/16 old size holes were this size. where did you get the rivet gun from. I'm hoping that I only need to get one more popped.

nickmerc 10-07-2010 03:49 PM

I did a google search for one. I bought it years ago. It is a Marson V-2/79014. It can pull all materials of blind rivets from 3/32" through 3/16". It is not rated for structural blind rivets. This should be fine for anything on smaller boats. They also make beefier ones if you want to set larger rivets.

caver504 10-07-2010 07:14 PM

thanks. I'll check it out if it looks like I need to pull more.


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