Correct Starcraft rivets?

[starcraftkid]

I'm repairing an older Starcraft boat and need to know what size and type of head rivet the originals were?
(Brazier head, truss head, etc?) The original rivets are 3/16" diameter but what length do I need to order to reinstall several ribs and a bench seat in an old Super Star?

 

[jigngrub]

Will these rivets be exposed or covered by decking and such?

If they'll be covered or you're not really concerned with aesthetics you can use closed end blind rivets for a one man quick and sure fix installation:
https://www.youtube.com/watch?v=L0MA1-5NXjs&feature=related

 

[starcraftkid]

They're on the side of the hull, they attach the bench seat and seat braces to the hull. Someone before me removed the middle bench seat and just sealed up the holes with caulk. I want the factory looking rivets. I also need to replace a few ribs, I have a parts boat to steal the ribs from, but need the right rivets to match.
I can get rivets that will work but they have big round looking heads, these rivets are sort of flat, and only slightly rounded. I'm not sure what type to order or how long the rivet needs to be. The metal being riveted is thin, maybe 1/8" total when compressed together. I figure a rivet that's maybe 1/4" or 3/8" long before being bucked would be about right, I can see that some of the factory rivets are pretty long in the inside, so they didn't worry much about extra length on the inside and I want the finished product to look original and un-tampered with.

 

[jigngrub]

To add further:

If you want to go with solid rivets, have some help and love to beat and bang (most men do!) here is the info for figuring solid rivet length:
http://constructiontractors.tpub.com/TM-9-2320-303-24-2/TM-9-2320-303-24-20403.htm

Basically you add up the thickness of the 2 material you want to fasten together and add 1.5x the rivet diameter

Soooo... for example, if you're using 3/16" diameter rivets and the thickness of the 2 materials you plan to fasten together equals 1/8" you'll want 1/8+3/16+3/32=13/32 length, but they don't sell that length so you'll round up to a 13/32 or 7/16" length.

Go to JayCees rivets online and look at the solid aluminum rivet specs and pick out the style head that matches your existing rivets, I'm thinking it'll be the Brazier head. Install the factory Brazier head on the outside of the boat and buck the inside end.

Buy a box of 100 rivets and practice bucking before you start installing the rivets on your boat for the best results.

 

[starcraftkid]

The head diameter is 7/16" give or take a few thousandths, the shank is 3/16" but the reach varies. Apparently the factory didn't worry about the reach, the amount of rivet showing on the inside on the original rivets all over these boats vary by as much as a 1/4". The rivet heads are rounded and very low profile. I've got some here marked 'Brazier head' but they have a small flat area in the middle of the head, they don't match the originals.
I went online and most sites ask which alloy I want? 1100F or 2117T4?
I have at least 30 old boats out back, just about all use the same style rivet, so I'm not thinking of a lot of 100 rivets, I need to buy these by the pound. I've got a few projects that need several hundred rivets. I'm thinking more like a 20lbs of rivets.

I also thought you were supposed to buck rivets from the round end or the head? The rivet driving set I've got is an airframe repair kit, its got a dozen different drivers all with different shaped bits to fit the rivet head, and a half dozen anvils to get into tight spots. The air hammer is a short through, high speed model that buzzes more than bangs on the rivet. It hits far faster than a standard air hammer.

I know that if I get the wrong alloy chances are good that there could be some dissimilar metal or corrosion issues, especially since these boats see saltwater.

 

[jigngrub]

See if any of this info helps:
https://www.google.com/search?sourc...h&gs_l=hp..10.41l1154.0.0.0.19762...........0.

 

[Watermann]

The 1100 rivets are very soft, when using solids for structural components use the harder 2117 rivets. If your fastening 2 pieces of AL then 3/16" x 3/8" long braziers will do the job just fine.

 

[starcraftkid]

None of the original rivets have any head dimples, so I take it they're all soft rivets? (1100F?)
From what I've read it looks like I need brazier head rivets in 3/16" or modified brazier head for any holes that require drilling out to 1/4"?

 

[Watermann]

You may be over thinking this a bit, a solid rivet is a very simple object, other than head shape and size the only other variable is hardness. I have driven in dozens of solids so I'm offering my experience not what I've read somewhere. Use the harder 2117 brazier head for your job for the boat structure, all of my SC rivets are hard, none are the soft 1100's. Get a 3/16" brazier head rivet set for your air hammer and I also used some 5200 on all of the rivets driven below the waterline. If you have a few extra bucks look into getting a set of Cleco's and pliers too, they are awesome for holding your work together. Below is a pic of the Cleco's holding on patches on my hull.



I don't see why you would want to drill the holes out to 1/4"?

 

[starcraftkid]

My biggest concern is appearance and making the final result look factory. None of the rivets will be below the waterline.
The original rivets seem pretty soft, the few that were holding the remains of the cut up bench seat in the good boat came right out with little resistance.
I drilled out all but two on each side, the remaining two just popped off when they were the only rivets left.
I called one dealer who in turn had a factory rep call me and I was told that soft rivets were used for corrosion purposes. They would rather a rivet fail than a hull panel.
He also said that even a 1100F rivet was good for more than 200psi or shear strength and due to the number rivets on each joint, strength was not an issue. This would explain why rivet heads tend to corrode off with no surrounding damage.
I also called an engineer buddy who deals with marine structures at work, he said that he wouldn't consider a boat hull a structural load but more a static load when it comes to choosing a rivet. Since there are so many rivets and multiple joints, no single rivet is ever under any real load, if it is, there's already been a major structural failure that replacing a few rivets won't fix.

 

[jigngrub]

The soft rivets are also the reason the rivets stretch and leak, and also the reason rebucking them doesn't work for very long.

I agree that no one rivet in a boat is under extreme stress, but I'm also sure that some rivets in different parts of the boat are under more stress than others. These will be the rivets that stretch, loosen, and leak. Replacing these weakened and leaking rivets with a stronger rivet should alleviate future leaking problems.

 

[starcraftkid]

The rivets in question here will be holding a bench seat in place, and the boat doesn't have any leaks after 45 years of use - without two of the bench seats in place.
It doesn't leak a drop. The original owner drilled out the original rivets and put the bench seats in the attic. I got the boat from an estate sale. It was registered and in use this season.
He had a makeshift center console and steering wheel mounted in the middle. I tossed the 3/4" wood floor and 200lb console he had in it and plan to put it back to stock. I have everything he took out except for the rivets.
The plan is to put in a lighter floor over a single cedar center support using the inside of the spray rails to support the outer edges of the floor. The floor will sit flush with the bottom of all three bench seats.
If the boat didn't look almost new, I wouldn't worry about matching everything up.

 

[jigngrub]

The rivets in question here will be holding a bench seat in place, and the boat doesn't have any leaks after 45 years of use - without two of the bench seats in place.
It doesn't leak a drop. The original owner drilled out the original rivets and put the bench seats in the attic. I got the boat from an estate sale. It was registered and in use this season.
He had a makeshift center console and steering wheel mounted in the middle. I tossed the 3/4" wood floor and 200lb console he had in it and plan to put it back to stock. I have everything he took out except for the rivets.
The plan is to put in a lighter floor over a single cedar center support using the inside of the spray rails to support the outer edges of the floor. The floor will sit flush with the bottom of all three bench seats.
If the boat didn't look almost new, I wouldn't worry about matching everything up.

I understand that, but you haven't installed the bench yet either.

... and I was speaking more in general terms for the 30 old boats you have out back that're going to need the 20 lbs. of rivets.... or are all the rivets below the waterline in those boats good?

 

[reelfishin]

Nearly every aluminum boat I've dealt with has used soft rivets from the factory. I suppose this is for two reasons, first of is the fact that driving hard rivets would deform the soft aluminum hull, and second for the corrosion factor.
I also figured that they intend for some movement at the rivet during expansion and contraction due to temperature change. If the joint was so strong that things couldn't move it would no doubt crack.

Also consider the fact that in all high stress joints on these boats there are many rivets doing the job, not just a few. With a 217 psi tensile strength, if a 1100F rivet won't do the job, there's a major design flaw in the hull.
I've owned dozens of aluminum boats and repaired more than double that amount over the years, nearly all rivet failures I've seen were from corrosion not overload of the rivet. If the rivet is stronger or harder than the hull, the hull will no doubt suffer more damage than the rivet which would have taken only pennies to replace versus the entire hull or panel.

Repair wise there is no problem with using the harder 2117T4 grade rivets but down the road if corrosion is an issue, it may well attack the hull vs. the new rivets. For the most part, harder rivets are used more in airframe repair or where pressurizing/depressurizing is an issue. When it comes to a boat, the hull acts as one unit so no individual rivet ever takes on any more of a load then the rest when it comes to the base hull assembly. The highest stress points for any rivet may well be the bench seat rivets since very few often are asked to hold your own weight but when you figure that each rivet is rated at say 217lbs+, multiplied by say 12, (Super Star models I believe have 6 rivets per side for each seat bracket), your looking at over 2600lbs total.
With that in mind, its also more likely for a harder rivet to pop or shear under stress rather then to just loosen, personally I'd rather deal with a loose rivet than one that's popped and missing and possibly leaving a wide open hole.

A rivet must also expand when its bucked, this is what seals the hole, not surface pressure. There's actually very little compression force in between the head and the tail of a bucked rivet.

 

[Watermann]

I'm repairing an older Starcraft boat and need to know what size and type of head rivet the originals were?
(Brazier head, truss head, etc?) The original rivets are 3/16" diameter but what length do I need to order to reinstall several ribs and a bench seat in an old Super Star?

Guess I'm confused after reading you're initial post. I thought you were replacing several ribs too and if they're above the waterline then I really would like to see a pic of your particular boat.

Use what ever you think is best, it sounds to me like you have more than enough info.

 

[jigngrub]

I have at least 30 old boats out back, just about all use the same style rivet, so I'm not thinking of a lot of 100 rivets, I need to buy these by the pound. I've got a few projects that need several hundred rivets. I'm thinking more like a 20lbs of rivets.

Not all of you material thicknesses will be the same so I wouldn't buy 20 lbs. of just one size rivet, I'd break it up into about 2 or 3 different sizes... maybe 4.

 

[starcraftkid]

Guess I'm confused after reading you're initial post. I thought you were replacing several ribs too and if they're above the waterline then I really would like to see a pic of your particular boat.

Use what ever you think is best, it sounds to me like you have more than enough info.

The ribs are actually on a different hull, I've got 5 boats, I'm trying to make three perfect ones. The one I cut the ribs from is crashed on one side, the one with the seats out had the seats removed by the last owner. The third needs the top rail repaired and the wood seat tops replaced.

So far I'm more concerned about rivet hardness than before. If I go by the appearance of the stock rivets on these boats, they're all soft rivets.
I've read that the softer rivets are more resistant to corrosion, and they're easier to buck, and the soft rivets may compress and seal better.
Yet I also read that 1100F rivets are super soft and made from 99% pure aluminum.
If I do a punch test, the hull skin is softer than the original rivets, but a lot. But a local boat yard here tells me that if I go with the harder rivets I'll regret it both due to corrosion, head failure, and that I'd be lucky to drive them all without damaging the hull.

I guess all I need to really know is what grade or hardness the original rivets are?
Could the original rivets be hardened rivets which weren't marked with a dimple in the middle?

 

[Watermann]

Yeah I was just replying to your thread with advice from my experiences with solid rivets and I stick with the advice of using 5200 below the waterline on the replacement rivets.

My Chief's factory rivets are all dimpled and they're just fine.

Here's some more reading for you if you haven't seen this page yet.Down the page you will see the make up and metal content in each material. You'll see the 2100 grade as the most workable with a 95 hardness the same as 6061 marine grade hull material that's most common.

Take some pics and post them of your project boat.

http://youboat.net/diy/metalBoats/aluminumAlloys.aspx

 

[starcraftkid]

Yeah I was just replying to your thread with advice from my experiences with solid rivets and I stick with the advice of using 5200 below the waterline on the replacement rivets.

My Chief's factory rivets are all dimpled and they're just fine.

Here's some more reading for you if you haven't seen this page yet.Down the page you will see the make up and metal content in each material. You'll see the 2100 grade as the most workable with a 95 hardness the same as 6061 marine grade hull material that's most common.

Take some pics and post them of your project boat.

http://youboat.net/diy/metalBoats/aluminumAlloys.aspx

According to that link, 2xxx aluminum alloys contain copper? Isn't copper the last thing you want on a hull in saltwater? I do know that if you paint the bottom of an aluminum boat with a copper based bottom paint you get pretty severe corrosion.

 

[Watermann]

Last thing you want to leave sitting in salt water is your tin boat period :lol:

All of the AL marine grade alloys contain copper (CU). Not sure anything is going to be perfect enough.