Super Jet Hull repair

[FX1 696]

After coming back from the lake yesterday, I gave the ski a quick look to make sure everything had held up after my first ride of the season. I noticed there was a big gouge on the bottom of my hull (squarenose). It was not there last year, and I knew it did not happen on this ride. I'm guessing it's an old injury and the previous owner used a quick fix of some sort (see black colored filler). This looks to be about 1/4 inch deep, and you can see just how many layers are chipped away in the pictures.

1) How thick is the bottom of the hull? I can't see any damage in the inside of the engine compartment, but it must be close.
2) Is it best to grind anything away with a dremel before filling this in?
3) I don't want to pull the whole engine and everything - is it possible to repair working underneath the ski, or will gravity mess up everything I've done as it's hardening?
4) Are there any good, recommended fillers, or do I need to glass over this?

 

[Quinc]

looks like it is starting to rot. grind it out and put a couple layers of biax on it.

 

[FX1 696]

Thank you for being my lone supporter, Quinc.

I got to work tonight - first, a good sanding to see just how much "rot" had spread. Here's what I found, a patch of cancer about 6 inches long.



No use feeling sorry for myself, so I started grinding away. But I must say, I was confused by how much moisture kept accumulating. I would dry the patch, start grinding, then it would begin leaking and forming a sort of paste when it combined with the dust.



After several minutes of this, I realized there could only be one cause - leaking water from the inside? Couldn't be, I vacuum out the engine compartment after every ride and it had been drying for a while. I formed a hypothesis that this "cancer" had impeccable ability to hold water, like a sponge. Kept grinding, more cancer. Keep grinding more, just to reveal more cancer. I thought to myself - this is getting dangerous, I must be close to poking through the inside of my hull by now. I take a look under the hood and peel back the annoying piece of turf lining my engine bay; I've always wondered why that was there... (Sorry pic is upside down, but you can see turf underneath battery tray and gas tank.



Turns out, this previous owner has a masters degree in the art of "cover-up". Not only was the outside masked with his mystical black goo, the inside of the engine compartment had been "reinforced" and painted white. As if that were not enough, he threw some turf on top as well. I'll admit, some red flags should've went off when I was looking to buy this thing.

So back to the story, I pull out the battery and gas tank, peel off the sheet of turf to reveal this.



Pressing on it, I can feel there's water underneath. Might as well grab a flathead screwdriver and start peeling this up to see what's underneath.



Low and behold, the hole I was suspecting to find.



I've already got a flipping hole in the bottom of my ski, so might as well just finish the job and cut out all the rest of the affected area out. This is where she stands as of tonight.

 

[FX1 696]

So I'm looking for opinions on how to glass this hole - would I be able to duct tape and seal off from the bottom, glass from the engine compartment, let it dry, remove the duct tape and glass from the bottom?

 

[Christian_83]

Thats no biggie. Clean outside really good.
Clean inside good, prep and scuff the indesige, with about 2" wider around the hole.
Put a piece of plastic, that just covers the hole from the outside. Tape the plastic down.
Now start working from the inside, with the glas. put pieces cut the the size of the hole to fill up/out the hole, after this put pieces with around 2" wider than the hole. preferably 4-5 layers of around 200-300 gram/m2
After this beauty dries up. you can ad 2-5 layers from outside with also 2" wider than the hole.

 

[Christian_83]

Search youtube, there is alot of videos covering subjects like this. Its nothing to hard or fancy you will be back on water in no time.
Use a good epoxy and use woven or biax glas (not chopped matt)

 

[augustaf]

Like Christian_83 says: use epoxy- don't even think about using polyester resin! You have to have a dry (!!!!) surface, grease free and roughed up with the coarsest sand paper available (maybe 36 grit). That way you attain a mechanical bond, a chemical bond is only possible while the epoxy is still "green"- just a few hours old.

 

[FX1 696]

Thats no biggie. Clean outside really good.
Clean inside good, prep and scuff the indesige, with about 2" wider around the hole.
Put a piece of plastic, that just covers the hole from the outside. Tape the plastic down.
Now start working from the inside, with the glas. put pieces cut the the size of the hole to fill up/out the hole, after this put pieces with around 2" wider than the hole. preferably 4-5 layers of around 200-300 gram/m2
After this beauty dries up. you can ad 2-5 layers from outside with also 2" wider than the hole.

Thanks, this was what I was thinking but I wasn't sure how to seal off the bottom as I'm laying glass from the top. What kind of plastic do I use, like a ziplock bag or saran wrap?

 

[nucleus_coolins]

Ya follow how Christian said, west system has some good pics and documentation that helped me when doing what he described.


U can use duct tape stuck to duct tape so its not sticky where the void is and then stick that to the outside of hull as a backer.

And im not sure if its necessary but the 2 corners of your cut are pretty sharp angles, might wana drill small hole on each end to prevent it from starting a crack from those edges later on.

 

[Christian_83]

Thanks, this was what I was thinking but I wasn't sure how to seal off the bottom as I'm laying glass from the top. What kind of plastic do I use, like a ziplock bag or saran wrap?

Use a ziplock back, a shopping back. any kind really. just to make a smooth surface to lay the fiberglas up on, from the inside. When you done the inside and its dry, the back will slip right off

 

[FX1 696]

the 2 corners of your cut are pretty sharp angles, might wana drill small hole on each end to prevent it from starting a crack from those edges later on.

I was questioning this myself, I'll be sure to do this.

 

[FX1 696]

Use a ziplock back, a shopping back. any kind really. just to make a smooth surface to lay the fiberglas up on, from the inside. When you done the inside and its dry, the back will slip right off

So I need to wait until the top side is completely dry before working from the bottom? I've heard that it's stronger if I do it all at the same time, and it all dries at once. But not sure if that's possible in this situation..

 

[Quinc]

Rough up with 36grit, wear nylon gloves, wipe everything down with acetone, and use epoxy two part resin. I like to use 6oz Sglass and 12oz biax.

Get the medium or fast dry 635, also get the pumps
http://www.uscomposites.com/epoxy.html

Also get a roller:
http://www.uscomposites.com/fgrollers.html

1208 biax glass
http://www.uscomposites.com/specialty.html

Buy a box of 2" brushes and vinyl gloves from harborfreight

Some details here from when I repaired mine.
http://www.x-h2o.com/index.php?threads/basic-sn-build-completed-tuning-time.139048/

 

[Christian_83]

So I need to wait until the top side is completely dry before working from the bottom? I've heard that it's stronger if I do it all at the same time, and it all dries at once. But not sure if that's possible in this situation..

Well, yeah ideally you do all the casting/repair in one bit - so all wet - in wet.
But i think it will be ALOT easier for you to control, if you do it in the steps i mentioned, especially if its the first time
and trust me, that repair, made over 2 times, with epoxy and some of the fiber @Quinc mentioned - it will be ALOT stronger than the OEM bottom deck (SMC stuff) that yamaha uses.

 

[augustaf]

Search youtube, there is alot of videos covering subjects like this. Its nothing to hard or fancy you will be back on water in no time.
Use a good epoxy and use woven or biax glas (not chopped matt)

And while you're on youtube, look up "peel ply", a release cloth more practical than plastic- been enjoying that since before the internet came to be.

 

[FX1 696]

Get the medium or fast dry 635, also get the pumps
http://www.uscomposites.com/epoxy.html

So if I mix at 3:1 for medium dry, how many ounces do I need to order total for a job like this?

 

[Quinc]

So if I mix at 3:1 for medium dry, how many ounces do I need to order total for a job like this?

Buy a gallon. And extra glass for the next time you need it.

 

[FX1 696]

Thank you for all the help and suggestions, but I was waiting to update this thread until I could steal some leftover footholds material from a friend in Texas. I bought a bunch of 3oz bottles so I could bring back the epoxy and hardener in tiny individual bottles on the plane. TSA was not enthused about this idea, but they let it pass.

The first thing I did was drill holes on the ends of the sharp angles - thanks for the suggestion @nucleus_coolins



Then, some more cutting and sanding to rough it up from the top side, and tape a plastic bag on the bottom side.

 

[FX1 696]

Next, onto the glassing. The donated material was very thin. I began by cutting out the shape with paper, then tracing it onto the glass.



It took about 50 layers of resin, glass, then more resin to cover the thickness, about 1/3 inch. Then scratching from the top side with 36 grit before I lay down a larger piece.



Put on some larger pieces.



Then cover it all up with resin, and wait for it to dry.

 

[FX1 696]

After drying overnight, I peeled off the tape and started sanding, then scratching up the bottom with 36 grit.



Lay down a few layers of glass:





I waited for that to dry and sanded it smooth. Been riding about a month with it like that. I'll probably paint the whole bottom black over winter. Any suggestions on this? Do I need to flip it upside down or is there another way? Take it some place for professional paint or just a few layers with a spray can?

Thanks all, for your input. Greatly appreciated.