Aluminum:Big hole all way thru keel cap, Help!

[Tim Frank]

Re: Aluminum:Big hole all way thru keel cap, Help!

You might want to do a search in these forums on "bucking rivets" or "rivet replacement" or a few other similar combinations.
Rather than trying to seal leaking rivets,, replacing them is better option and easietr to do than you might have thought.

 

[Old Ticker]

Re: Aluminum:Big hole all way thru keel cap, Help!

I didn't mention it above, but we are tightening marked loose rivets before gluving it. Thanks.

 

[sschefer]

Re: Aluminum:Big hole all way thru keel cap, Help!

4000 because its aluminum ?
5200 for glass ?

Yep..

 

[redfury]

Re: Aluminum:Big hole all way thru keel cap, Help!

As far as the Tex goes, too thin and it will take longer to cure, too thick and it will overheat itself and not cure properly. Tex is exothermic, so it has to have heat to cure properly. As John has found out, you need to add heat if you are putting it on thin or it takes longer to cure.

My first thoughts on that hole was to get an aluminum bar formed and welded from the inside and then patch welded and ground smooth from the outside.

However, I'm in no position to claim experience with aluminum, nor riveted aluminum and the issues with heat from welding...that was simply my common sense-over engineering reaction to the hole...

What I do know though is that Tex is not the cure for a hole like that. It will expand at a different rate than the aluminum will, cold or hot, and eventually that stress will weaken the bond between the two in a situation like that-so it would be a temporary fix, though it may last a few years....but when will it fail? The middle of the lake? Retrieving the boat onto the trailer? In storage over winter? You'll never know, and not being able to put 1000% trust in your vessel on water is not worth the penny saved yesterday.

 

[ondarvr]

Re: Aluminum:Big hole all way thru keel cap, Help!

Forget the Marine Tex, it will of little value if you're going to use Gluvit on the inside. Just get everything off the outside so you can find all the problem spots.

 

[Old Ticker]

Re: Aluminum:Big hole all way thru keel cap, Help!

I've already ordered and received the 3M 5200, now on here they say I should have gotten 4200. I researched both products and neither says specifically for aluminum. Does anyone have experience with using both to compare results on aluminum? What I'm reading says that the 5200 is a much stronger bond. Thanks

 

[sschefer]

Re: Aluminum:Big hole all way thru keel cap, Help!

I've already ordered and received the 3M 5200, now on here they say I should have gotten 4200. I researched both products and neither says specifically for aluminum. Does anyone have experience with using both to compare results on aluminum? What I'm reading says that the 5200 is a much stronger bond. Thanks

I just got off the phone with my old 3M rep and he says that the 5200 will work fine for bonding metal hardware to wood, fiberglass and gelcoat. In your case you are sealing more than you are bonding so it should work fine. The 4000 is desgined for bonding/sealing metal to metal but like metal, it has less elasiticity than the others. I think you'll be o.k. as long as it's not your primary sealant for the patch. I'd use a rubber gasket between the patch and the hull with 5200 as the extra measure.

 

[ondarvr]

Re: Aluminum:Big hole all way thru keel cap, Help!

I would skip the gasket, it will be the week point in the seal.

 

[sschefer]

Re: Aluminum:Big hole all way thru keel cap, Help!

I would skip the gasket, it will be the week point in the seal.

A pro shop wouldn't. The one that did mine didn't and they make their living at fixing boats right.

 

[ondarvr]

Re: Aluminum:Big hole all way thru keel cap, Help!

So what type of gasket would you use on an uneven aluminum to aluminum seal when new they don't use gaskets in the rest of the hull.

Bedding it in a good quality product rated for below the water line will work better.

 

[sschefer]

Re: Aluminum:Big hole all way thru keel cap, Help!

So what type of gasket would you use on an uneven aluminum to aluminum seal when new they don't use gaskets in the rest of the hull.

Bedding it in a good quality product rated for below the water line will work better.

Actually they do, all of the seams use a rubber gasket material between them. I can't remember the name that it goes by but most aluminum boat repair shops are very familiar with it. When I get my camera back I'll take some shots of the repairs that were done to my hull. I filled the boat with water afterwards and there were no leaks.

 

[Mark_VTfisherman]

Re: Aluminum:Big hole all way thru keel cap, Help!

I just got off the phone with my old 3M rep and he says that the 5200 will work fine for bonding metal hardware to wood, fiberglass and gelcoat. In your case you are sealing more than you are bonding so it should work fine. The 4000 is desgined for bonding/sealing metal to metal but like metal, it has less elasiticity than the others. I think you'll be o.k. as long as it's not your primary sealant for the patch. I'd use a rubber gasket between the patch and the hull with 5200 as the extra measure.

A thin rubber gasket- even Aubuchon stuff- with 5200 on both sides will be fine. I would not only screw the metal in place but would rivet it as well. Make the patch extend well past the damaged area.

This is not an uncommon damage for boats around here. Lots of running up on concrete or gravel boat launches or beaching with all the stony shorelines will do it. I have even replaced 1/2" or better on my fiberglass boat's keel/prow several times because of beaching. Last time I bedded a piece of oak in as a "wear bar" which has helped.

 

[ondarvr]

Re: Aluminum:Big hole all way thru keel cap, Help!

The problem with rubber gaskets on an uneven surface is when the rubber isn't thick enough to fill the entire gap, this means you're still relying on the sealant to make it water tight, the rubber gasket alone won't do it.

Now you're depending on the sealant and the rubber to hold up, in some places the rubber is compressed very tight and in others its not, as the repair ages the rubber tends to deteriorate and lose it's elasticity at a different rate than the sealant, that's when it may start to leak.

I did a great deal modifying on my Aluminum jet boat in converting it from an inboard jet to an out board jet, I achieved the best seals when it was aluminum to aluminum and a 3M sealant. 7 years later and there hasn't been a single leak. I also lived on the salt water for many years growing up and had many aluminum boats that were abused terribly (rocky shoreline, no sand), I found Gluvit and 3M sealant products to be my best friend.

Can a rubber gasket be used?yes? is it needed no.

 

[Old Ticker]

Re: Aluminum:Big hole all way thru keel cap, Help!

Thanks for all the input, been out of town to the lake, without the boat of course We had lots of cleanup to do with trees and limbs from the infamous icestorm here in Arkansas in Jan. Back to the repair, we've coated the top and bottom of hole with marinetex grey, with fiberglass screening in the middle. I'll post some pics of this later today for a proper update. We're about to start tightening rivets in prep for the Gluvit all over floor area. We have the keel cap made from thick aluminum. We are wondering which side to drill out the rivets from, flat side or small tip side? Going to remove some rivets on old keel cap, and replace with trusshead SS screws and 5200 to bolt on the new cap. Didn't want to drill new holes in the boat, figured this would be the best way. Thanks again

 

[Old Ticker]

Re: Aluminum:Big hole all way thru keel cap, Help!

I got the pics of the patch on keel hole, its marine tex grey. Notice in the foreground of the "inside" pic, the yellow/tan stuff lining the rib seam. There are at least 3 such places on the boat bottom, one we just located last night after jacking boat up away from bunks. It's on the right side "runner" going down right side on bottom of boat near where it runs into back on boat. There are 2 fiberglass patches on each side of this "runner" on the bottom, then on the inside where the back of boat meets bottom (under the splashwell), there is that yellow /tan stuff all along seam. We're concerned about these places, can't really get them cleaned out well. We're planning to pull motor and flip boat to get at the bottom. It has flaking paint all over it, and lots of leaky rivets. Were planning to strip off the bad paint, peel away all the fiberglass patching and JB Weld spots over some of the rivets on bottom, then flip boat put some water in and remark the leaky rivets. (There will be many more now that we've stripped all JB Weld from inside the boat.) Then tighten leaky rivets, then apply Gluv it. Do you have any recommendations on the leaky seams, especially where the yellowish goop is globbed on either side of a rib? wondering if the water will come up under rib and flow out the ends?? And which side of the rivets do we drill out flat on the outside or the inside? We've got to put the alum keel cap patch piece we had made over the patched hole and figured the best way was to drill out some of old rivets and replace with SS truss head screws in holes that were already there and not new ones we drilled into boat. Is that right? We're pretty sure this poor boat was used as a stump jumper on some nasty shallow river over in the bottom land. We're still real close to patchn' her up and selling her for that very purpose, to the duck hunters over here. I've located a 15' Starcraft runabout with 40 hp Evinrude (motor needs work, been sittin'), its a 72 model with original paint/condition and paper work for $850. Thinking about going and buying it. Any and all suggestions are appreciated.

 

[Huron Angler]

Re: Aluminum:Big hole all way thru keel cap, Help!

A thin rubber gasket- even Aubuchon stuff- with 5200 on both sides will be fine. I would not only screw the metal in place but would rivet it as well. Make the patch extend well past the damaged area.

This is not an uncommon damage for boats around here. Lots of running up on concrete or gravel boat launches or beaching with all the stony shorelines will do it. I have even replaced 1/2" or better on my fiberglass boat's keel/prow several times because of beaching. Last time I bedded a piece of oak in as a "wear bar" which has helped.

Hey Mark do you have a picture of this oak "wear bar"? I'm Curious what that looks like and how it is attached. It sounds like a pretty practical way to add some protection. Thanks.

 

[Mark_VTfisherman]

Re: Aluminum:Big hole all way thru keel cap, Help!

Hey Mark do you have a picture of this oak "wear bar"? I'm Curious what that looks like and how it is attached. It sounds like a pretty practical way to add some protection. Thanks.

Umm, well, it's sort of buried in epoxy paste, so you can't really see it anymore.

Getting it ready for fishing, and I just this afternoon sanded that area and applied fiberglass over it as well, the first of several layers I am adding. The oak gets wet when it has a hard "impact" with stones because it chips the epoxy. Then it swells and fractures more epoxy... So I am covering in glass, and hope to find a two-foot length of something to adhere as a keel guard. Have thought about epoxy pasting on an aluminum strip, but expansion with temp changes concerns me.

Anyway- what I did was to cut a 3/8" x 18" strip from a vertical grain section of red oak board, hand planing the ends to a steep knife edge on the leading and trailing inch. I jacked the prow up off the trailer and blocked it for safety. Then I mixed up the epoxy paste (used white "marine" PC-11), buttered the back of the oak piece, and stuck into place. Of course my prow is curved, and oak is stiff...so I made two short sticks 1/2" less than the distance from the trailer tongue to the keel, one for the front, one sized for the rearmost portion. I wedged them in place, jacked up the trailer to take the blocks out, and then let it down carefully until the oak fully bent and conformed to the shape of the prow/keel, and then I closed the lowering valve tightly. I used a 1-1/2" putty knife to spread the extra epoxy and squeeze-out into a filet around the oak, and left it until the next afternoon to cure. I pasted on another coat of epoxy paste to bury oall the oak, and painted with white duplicolor lacquer.

It's been stuck there with no screws for two years. That's why I just shake my head and ignore it when I hear people dissing PC-11! Maybe some better stuff out there but it's bond is stronger than the tension of a piece of dry-bent oak.

It took a few hits- beaching at Lake Eden, the ramp at Elmore once, a buddy hitting the trailer pretty good trying to load the boat on. It always damaged the epoxy over the wood, requiring an repair to the finish, but other than that and chips in the oak, it's just on there!

Anybody have thoughts on what to do for a keel guard? Aluminum, or some piece of HMW plastic? I won't spend $150 on a keel guard when it will only fit the forward two or three feet at most.

The wood has worked real well so far. No more wear into parts of the actual hull anymore.

 

[sschefer]

Re: Aluminum:Big hole all way thru keel cap, Help!

I bought a 6' keel guard. I haven't installed it yet but it seems like a pretty darn good solution. My bottom will be white and so is the keel guard so it will be hard to see it.

My Dad had one made out of stainless steel and fitted to his boat. They actually tacked it together in place and it was glass over wood boat. Dad would often talk about how amazed he was that the it didn't burn the boat. That thing was still in perfect shape when he sold the boat 10 years later. He got a lot of comments on how nice it looked too.

 

[Mark_VTfisherman]

Re: Aluminum:Big hole all way thru keel cap, Help!

I.....My Dad had one made out of stainless steel and fitted to his boat.......

Dear Huron Angler:

So sschefer's comment inspired me...I am going to epoxy paste a metal crown on my bow / keel since that seems to be the only place that takes a beating- never had to patch anything but where the horizontal keel transitions up to the more vertical sweep to the prow.

If I don't actually do this today I may post this question as a new thread, but:

What does everyone think? Should I use aluminum or stainless steel? I am planning to buy a piece of 1/4" aluminum 1"x36" but might go stainless steel if I can think of an advantage or one is suggested. I can form aluminum easily with woodworking tools and shape it easily. Stainless is so stinking hard and not very malleable.

OK- in typing this post I just talked myself into aluminum. I will make a point to take pictures and start a thread. Probably will use PC-11 epoxy and no screws. I thought about using 5200 but I think the epoxy is a more dependable choice in this application.

Huron: stay tuned...might not do this this weekend as spies and satellite photos indicate that ice is out of Seymour Lake....

 

[Mark_VTfisherman]

Aluminum keel 'wear bar' on fiberglass boat

Aluminum keel 'wear bar' on fiberglass boat

Huron:

Basically one picture with two photos. I took a piece of 1/8"x1" and bent it to the shape of the "wear area" of my keel as it runs up the prow. Used my grinder to roughen up the backside, and PC11 epoxy to butter the backside, placing it onto the hull. I cut a board to wedge it in place until curing. Then I faired it up a little with more epoxy- Needs one more smooth coat and then sanding in this picture. Didn't finish as the lake was calling...

Because the dock at the launch on Seymour is not yet in, it got a good test run as we had to "beach" on the concrete launch- once going in and once going out. No fiberglass damage, not chips, just little scratches on the aluminum. which is perfectly ok with me.

Wished I had thought of that long ago! The oak was a step in the right direction, but the aluminum is better.