# Rib Replacement



## Drewski597 (Oct 26, 2008)

I have a ten foot jon boat I recently purchased to duck hunt out of, and while the hull is in pretty good shape the support ribs are not. The two in the center are either cracked or completely broken. I was wondering what would be the most effective replacement for these ribs. I've been looking at aluminum hat-section and aluminum angle iron but I'm not sure which would do a better job. Any other suggestions would be greatly appreciated.


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## Waterwings (Oct 26, 2008)

Post a pic if posssible. I'd probably go with some aluminum channel with a decent wall thickness. Do you have the capabilities, or know someone that can weld it for you? How did the original ribs get broken?


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## Drewski597 (Oct 26, 2008)

The Aluminum on the boat is pretty thin stuff, I have a friend that welds for a living and he said it wouldn't be worth welding. I'd say the whole boat probably weighs in at 40 or 50 pounds. The ribs broke (I'm just judging from observation) from being crunched under foot and flexing with the bottom of the boat, they were that way when I bought the boat.


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## Jim (Oct 26, 2008)

:WELCOME:

Thanks for joining! :beer:


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## Specknreds (Oct 26, 2008)

Are the ribs rounded or square? Pictures would help...

If rounded, is the rib made out of thin Alum. with little indentions or cripples another words they are not smooth? If so, your probably better off fabricating new ones and rivet back into place. 

If square, WW said the best method. If you can't weld it, Then you are going to need to fabricate flanges on both sides of the channel and rivet into place.

I had one with a couple of broke ribs that I simply put a plywood floor in and left the ribs alone. It lasted for years, but the boat stayed at the lake and I didn't trailer it.


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## Drewski597 (Oct 26, 2008)

Here are a few pictures of what I'm talking about. Sorry, I could have been more specific in my description.


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## Specknreds (Oct 26, 2008)

You described it pretty good. I thought that you were describing rounded ribs. If you boat is as thin as mine was, make new ones and rivet in.


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## Drewski597 (Oct 26, 2008)

What is an alternative to having someone bend out new ribs or would that be my best bet? Looking around in the local hardware store gave me the idea for L-angle aluminum but it's pretty high when you buy it from a retail store.


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## Specknreds (Oct 26, 2008)

You might have said, but I didn't see where you were from to help u out more. I picked some up reasonably at a local machine shop. It was left over scrap. Scrap yards are a good source. Any metal is sky high at this time.


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## ben2go (Oct 26, 2008)

The rib metal is called hat section.Most boat builders bend there own in a machine like the ones used to shape house gutters.



https://www.aircraftspruce.com/menus/me/aluminum_hatsection.html


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## bassboy1 (Oct 26, 2008)

Does it go up the sides, or just across the bottom?

If it goes up the sides, I would get some aluminum square, probably 6061 alloy, and cut and weld it in a U that fits perfectly in the boat. Cut it yourself with a hacksaw, and take it to a welder, and they should be able to do it without too much cost. Then, rivet it through the outside of the hull with 3/16 diameter pop rivets sealed with 3M 5200. 

If it just goes along the bottom, and butts up against the hull at the side, I would probably use the same square tubing and rivets, but you have removed the cost of the welder, and making the correct angle.


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## Drewski597 (Oct 27, 2008)

I've been searching around and I've about decided to use L-angle aluminum with solid aluminum rivets(1/2" head, 1/4" shaft by 3/8" long) But I'm not sure if 1/16" L-angle aluminum would be sufficient to give me the support I need. Any other input? 

Bassboy: I


bassboy1 said:


> rivet it through the outside of the hull with 3/16 diameter pop rivets s



I did a little test section witht the old rib and 3/16" pop rivets but they don't have the same diameter head as the original rivets and they don't seem to want to make the rib snug up to the hull very well. My concern is also that the diameter of the head isn't going to provide enough metal to really seal up the old holes or have sufficient area to "grab", and i'd hate for one to pull through. The holes are somewhat wallowed out from the old rivets moving around in them.


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## bassboy1 (Oct 27, 2008)

Drewski597 said:


> I did a little test section witht the old rib and 3/16" pop rivets but they don't have the same diameter head as the original rivets and they don't seem to want to make the rib snug up to the hull very well. My concern is also that the diameter of the head isn't going to provide enough metal to really seal up the old holes or have sufficient area to "grab", and i'd hate for one to pull through. The holes are somewhat wallowed out from the old rivets moving around in them.


I can see where your coming from, and definitely agree that conventional solid rivets will be ideal. A lot of people that I see online are adverse to using them, for whatever reason. Myself, I will use both about equally in various thru hull situations. Both have their advantages. 

For future reference, if the back side of the rivet head is not big enough, they do sell aluminum backup washers that you put on the back before you tighten it down. Usually will make the backside as strong/spread out as the head.


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## ben2go (Oct 27, 2008)

Most people use 1inch x 1inch x 1/8inch thick or 1 1/4inch x 1 1/4inch x 1/8inch thick.1/16 is to thin.It will flex and either pop the rivet out or wallow the holes out.


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## bobessary (Oct 28, 2008)

im not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod


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## bassboy1 (Oct 28, 2008)

bobessary said:


> im not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod


Not to mention, they are of a good quality. When you build a house in what used to be woods way out on the end of an old country road, you are bound to find a few while clearing land. Plus, they show up at the scrapyard every now and then.


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## Drewski597 (Oct 28, 2008)

I sure appreciate all the input, I was thinking this would be a good bit easier than it's turning out to be, but I'd be headed for a big wake up call if not for the help.


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## Ouachita (Oct 29, 2008)

You can use stainless panhead bolts with nylock nuts instead of rivets. You can get the size that will match your existing holes and they are stronger than pop rivets IMO. Just coat the hole and bolts with 5200m.


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## Drewski597 (Oct 29, 2008)

bobessary said:


> not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod



I never would have thought about a road sign. I'm in school, and our landlord's father aparently had an old sign the we found half buried in the woods. It's the perfect length for my ribs so when I figure out how to make some clean cuts and bends it'll be the new addition the my ten footer. Excellent idea. Bassboy was right... Woods and an old house seem to be the recipe for finding old road signs


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## bobessary (Nov 3, 2008)

Drewski597 said:


> bobessary said:
> 
> 
> > not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod
> ...



you can make cuts in those signs using a circular saw or table saw if you flip the blade backwards it makes pretty good cuts just another suggestion if you wanna try it


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## Waterwings (Nov 3, 2008)

> you can make cuts in those signs using a circular saw or table saw if you flip the blade backwards it makes pretty good cuts just another suggestion if you wanna try it



:shock: 


Sorry bassboy, but I highly recommend against that practice. Get a cutting wheel for your saw that's designed to cut metal. If you're cutting aluminum, make sure the wheel is for non-ferrous metal. _If_ the cutting wheel isn't designed for non-ferrous metal, it will "clog" the wheel and eventually/posssibly explode on you. Safety first! :wink:


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## phased (Nov 3, 2008)

I agree with WW. I bought 7 1/4" metal cutting wheels for my circular saw at Lowe's here for a little less than $5 each. It was a surprise as to how many/much cut I got out of a blade. And don't forget the safety goggles.


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## bassboy1 (Nov 3, 2008)

Waterwings said:


> > you can make cuts in those signs using a circular saw or table saw if you flip the blade backwards it makes pretty good cuts just another suggestion if you wanna try it
> 
> 
> 
> ...


Actually, I didn't post that (bobessary did) but I will defend it just as well. Not just any circular saw blade will work. Needs to be a carbide on. I have heard of people putting carbide blades on backwards for thin stuff, but I wouldn't try that, as I feel that it might try to rip the carbide tips off. Never heard of that happening, but I don't want to turn my blade around.

It isn't just one of those things that you often hear about "well I do this and it works fine..." 
Cutting aluminum on circular saws, table saws, and miter saws using carbide wood blades is common practice, often used by many welding shops and machine shops, if they don't have shear, or need odd shapes, and can't work with the rough edge a nibbler can sometimes leave. 

The thing is, the higher the tooth count the better. 60 and 80 teeth are better if you have them, but not always needed. When cutting on the table saw, we usually use an 80 tooth carbide blade. I regularly cut angle and tubing on the miter saw, with the 32 tooth blade, and usually use a 40 or so on the circular saw, although we have used a 12 tooth before. And, we do have both a vertical and horizontal bandsaw here at the house, so were it not safe, we have other options, but there is no safety issue, unless it is too hot to wanna wear long sleeves. 

Also, you can use carbide router bits to cut various things. Yes, we could make baseboard molding out of aluminum bar on the Delta shaper if we wish. Could make aluminum raised panel doors on it too. (May have just given me an idea for my next boat build.....  )

The only thing I can say is, wear long sleeves (hot shards flying - will leave your arm looking like it got attacked by a hoard of chiggers) and WEAR EYE PROTECTION!!!!!

Also, do NOT NOT NOT use an abrasive blade, like I am about to link too. That includes grinder wheels. They will clog up with aluminum, overheat, and blow up, and at 10,000 RPM (angle grinder speed) you do not want that to blow up.
https://www.mikestools.com/DW3508-DeWalt-6-1-2-x-1-8-Metal-Abrasive-Saw-Blade.aspx


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## Waterwings (Nov 3, 2008)

> Actually, I didn't post that (bobessary did)



Ooops, sorry about that. Anyway, you're correct on the use of metal cutting blades, as long as they are carbide tipped _and_ specifically designed to cut metal. Also, as you stated, do not use regular abrasive wheels, as they will explode as I also stated :wink: . Folks, if you're in the store looking for a metal cutting blade for aluminum, be sure and read the label on the blade. It should read for Non-Ferrous metal. Just because someone works in a hardware/home improvement store doesn't necessarily mean they know all tools/applications, so be leary of their advice if they respond to your question with a generic "uh, I guess it'll work". :shock:


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## bassboy1 (Nov 3, 2008)

Waterwings said:


> Anyway, you're correct on the use of metal cutting blades, as long as they are carbide tipped _and_ specifically designed to cut metal.


The difference is the rake of the teeth. The ones designed for aluminum will do _slightly_ better, but not enough to be worth buying a metal blade, if you already had a nice carbide wood cutting blade. The difference is in how aluminum feeds. Go slow with the cut, and you likely won't even notice the difference between the wood rake and the aluminum rake. 

One thing I didn't mention is to lubricate the cut line. At the house, we use this stuff.
https://www.bandsawbladesdirect.com/shop_ind.cfm?i=10
Bee's wax and parafin are also good. I have heard of people using candle sticks. You just smear it down the cut line, and it will lubricate as it goes. Some people will also lubricate the blade/drill. Just cut into one of the aforementioned items, and the blade is lubricated. I have heard of people cutting into toilet wax rings for blade lube.


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## dedawg1149 (Nov 3, 2008)

i have cut metals(aluminum) for years with a blade turn backwards never had a problem


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## bobessary (Nov 12, 2008)

dedawg1149 said:


> i have cut metals(aluminum) for years with a blade turn backwards never had a problem




thanks for the support on that dedawg i was just making the suggestion because most people have an old circular saw hanging around and most like some dull bits which work just fine on metal after they dont cut wood any more just turn em backwards just goes to show that there are many different ways to skin a cat


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