Making of the SNX Hull

Can't wait to see the ride plate mold. Standard size (not full width) I assume? Did you recess the bolt holes like a stock plate or make that area flush? I did the former and I'm not sure how I'll like how the part releases. I've seen it done both ways with composite plates and I'm thinking making the bolt holes flush with the plate surface would save some headaches.

Full width plate. I'm taking so much off the back, I want to be able to "tune" the length a little. I'm going to pull the mold from a flush surface and probably counter sink the bolt holes on the plate.

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Most of the prep work is done. The air dry clay I used hardened and separated, so I have to reset the dam with non drying clay.

Right after the first layer of primer went down I got a call that my 61 year old mother broke her arm trying to build a car port. So that delayed the mold about a week. I should have the mold pulled off by Saturday though, weather permitting.

And the carnage...
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Thanks for this. It makes my build seem less daunting.

Haha thanks. I have been watching everyone's build threads for inspiration. It's all been pretty easy stuff so far. More time consuming than anything. The most difficult part of the bottom deck is going to be the ride plate indentions and intake tunnel enlargement. The plan is to build up glass to match the height of the old ride plate indention area (from the inside), then pour foam to grab the shape. Hoping that wax paper will be enough to release the foam mold, then cut out the bottom and lay new glass against the mold. We will see how that goes.


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Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I used wax paper as a mold release for laying glass just on a flat surface, and it came off super easy.

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Ride plate area with new, unfinished chines

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High tech chine radius sander

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Since most the area is going to be cut off later on, I used regular bondo body filler. Layered it on thick and sanded it down. It took several cycles of body filler/sanding to get to a decently smooth finish.

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Next I made a dam out of clay and playing cards. I used air dry clay, which deformed, so I had to repeat this with non drying clay. Primer sprayed after that.

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Once the first coat of primer dried, sanded it with 320 and shot a second coat.

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Standard high gloss white enamel.

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Sanded the final coat with 400 and then wet sanded with 1000. Applied 3 coatings of mold release wax, and then shot some PVA.

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I used the gel coat dump gun with a smaller nozzle for PVA. I really didn't like how the PVA flowed from the gun. First time using this style of sprayer, so it might have been user error. The PVA would drip out the nozzle no matter what pressure and volume I used. I ended up with some fine mist and some larger droplets. I think in the future I'll either use a standard hvlp or try a smaller nozzle. Anyway, it's just a ride plate and I don't intend to make any visual carbon with this mold, so I ran with it. Worst case the mold doesn't release right and I have to redo it.

Gel coat. 10ml syringe. MEKP. Respirator.

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Gel coat came out of the gun a lot better than the PVA did. Sprayed a few coats until it was around 30 mils thick, then allowed an hour or so for it to tack before applying a layer of 1.5oz / sqft mat and tooling resin. Hopefully the mold cures correctly and the mat does its job to stabilize it. Tomorrow I will build up the rest of the mat and glass. Should have it pulled off on Monday.

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The moment of truth...

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And success...

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It isn't perfect, but it is a lot better than I was expecting. You can see what I was talking about with the PVA build up. There's some paint that pulled off with the mold, probably due to the inconsistent PVA application. You can see where the paint pulled up off of the plug.

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The paint was somewhat dissolved too. Perhaps the MEKP in the gel coat started breaking down the paint where the PVA didn't lay down right?? I don't know... Regardless though the mold pulled off without any damage to the gel coat. Only needs some minor sanding to clean up the little bit of paint and remove the orange peel.

A few things I would/should have done differently...
Prepped the plug a little better before spraying primer. There were a few pin holes that I could have done a better job filling.
Primer/paint/sand/wax before building the dam.
Build the dam out of waxed poster board or something similar.
Last layer of glass didn't lay down perfectly. Shouldn't cause any issue though, there's 16 layers alternating of 1.5oz mat (13.5oz / yard) and 18oz woven roving.

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And a shot after the PVA was removed. Not professional work, but I'm pretty happy with it for my first attempt at a mold.



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Location
Wisconsin
I use an hvlp gun at 25psi with a 1.4 nozzle when spraying pva. I found this works well and being careful not to hold the gun too close keeps tiny bubbles from forming. That's gotta be a hella stiff mold at 16 layers of mat/18oz. Looks excellent, especially for a first mold.
 
Thanks for the tip. I will try that when I get to the pole mold.

It is very stiff... I would rather have too many layers and waste a couple of bucks on glass and resin than not enough and lose 10 times that in mats and my time laying everything.


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With the ride plate mold done, I can get to shortening the hull and creating the recessed plate area for the full width plate. There's several ways to go about creating the recess. After a lot of thought I chose to fill the negative space inside the hull with glass and then pull a foam mold off of it. This turned out to be incredibly time consuming...

Started by marking the inside of the hull and measuring where the glass would go.

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18 12"x6.5" (i think it was 6.5...) sections of 1708 biax measured out and cut.

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Layered down a thick coating of epoxy/cabosil before laying up 9 pieces of 1708 per side. I used a cabosil thickened epoxy for wet out to help build up to the height I needed. About 1/3 the consistency of the "peanut butter" mix. I actually like this over straight epoxy. It holds the biax around bends/corners better.

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Using 1/4" particle board I cut out the rough shape of the hull and attached 2x4 pieces to secure to the pump area and offset the particle board from where the ride plate recess would be.

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2mil plastic drop cloth laid in the hull and fitted around the particle board dam.

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Pour foam in. Took about 12 oz of foam per side.


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Removed the dam and plastic and replaced the foam mold. Measured out the cuts, 7.5" off the back. Removed the foam and made three more cuts on each side for the ride plate.

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Prepped the glass area. Sanded with 80 grit, MEK to clear out any dust. Duct tape over the inserts to keep epoxy out. Foam back in place. Clay to fill in the gaps and somewhat form the shape.

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Wax paper to release the foam after the glass is set.

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Cut 3 12x8" pieces and 2 10x8" pieces of 1708 per side. Measured out the relief cuts as best I could. Had to make a few cuts while laying up, but it was pretty close.

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Layered on some heavily thickened resin over the wax paper and around all of the edges. Used lightly thickened epoxy to wet out the 1708. Once the 1708 was down, cabosil/epoxy in the joint between the two sets of glass, then 2 layers of 8oz 3" wide tape to tie them together. Same thing for the side where the ride plate will sit.

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^^^ all of that took 13 hours (not counting the time for the glass to set).

It's amazing how time consuming this is. The smallest little change could take an extra 10 hours to complete.


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I really want a lighter hull, so the thought to pull a mold off of it is in the back of my mind.


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swapmeet

Brotastic
Location
Arlington TX
I don't even know what to say. You're doing so much work... albeit in a relatively short period of time. My mind is blown.

The only thing I was thinking, after owning/ seeing/ riding projects like this is that 'thats gonna be a heavy mofo when you're done.'

But you've already pulled your first mold for a ride plate. I would say that if you DON'T pull a mold off this and make a light ski you'd be wasting your time. Not totally wasting, because you're obviously learning a ton... but its like sitting on 3rd base forever if you just ride that hull.

Hope your mom heals up soon, that break is rough... (I threw up in my mouth a little.)

Mine mom is 70 something and rides motorcycles with my dad all over the country... I'm like "shouldn't you be knitting something?"
 

iangdesign

Cats, lots of cats!
Location
United States
That is a lot of work especially on a square but you have to start somewhere...is the rideplat really going to be that thick?

It looks close to 1/2 inch...

Lookin GREAT though! I could never focus on something that long.
 
I wouldn't jeopardize hull integrity over a few pounds. If your good enough rider that's not going to matter anyhow.

Nice budget build, your doing a bang up job.
 
Thanks swap, she's doing a lot better. She is pissed that she can't get on the water for another 3 months, but besides that she's good.

It is a lot of work, but I enjoy wrenching/modifying/building as much, if not more than riding. Definitely a labor of love. I am doing as much as I can to keep the weight down. Each section is only getting enough glass to tie it in and then the entire bottom and top decks will get reinforced with carbon. Still it is going to weigh a little more than a regular sj. More than likely there will be a mold. Haven't decided if I want to ride the plug around for a bit or just pull the mold while the decks are a part already.

Ian, thanks! It's not going to resemble a square much at all when it's done. As far as I know Yamaha didn't change the bottom deck until 08, and that's where most of the work is at. The top deck is going to be cut down and reshaped quite a bit as well. Going to finish the bottom before I dive into that.

Ride plate will be ~1/4". The recessed area will get a little more glass to bring it to the correct height.


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I wouldn't jeopardize hull integrity over a few pounds. If your good enough rider that's not going to matter anyhow.

Nice budget build, your doing a bang up job.

Thanks! Although budget went out the window... Originally it was just going to be a ported 61x. Then a Jetmaniac big bore was the plan. Then I figured if we are going big bore then why not resleeve a 62t to 89mm. Then I was thinking, if we are dropping in new sleeves then why not add in a 4mil php crank since we can get the port timing correct by changing the sleeve depth. Well you need bigger than 38s to feed that... Then the bpipe plan turned into a pfp and a stock 155 turned into a Solas mag. Etc etc

When compared to the $25k skis out there this is still quite a budget build. It's all relative I suppose.


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Glass set and foam mold off

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Time to do something about that ugly rear lip..

Measure back 2.5" in the center and 2.75" at the rails. Attached a 5/16th dowel to center with duct tape, then bent each side back and down. Secured with more duct tape. Marked the cuts and pulled out the sawzall.

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Reattached the dowel to the back of the hull in the same fashion as before. Cut out some 1" thick XPS and superglued wedges to them.

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30 minutes of 80 grit later...

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Glued down in place

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Filled in the gaps and transitions with clay.

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Wax paper cut and secured over the clay/XPS.

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Lay up for the lip:
1) 8oz tape 28x3 (x2)
2) 8oz tape 28x6 (x2)
3) 1708 biax 28x6 (x3)

Reinforced the new rear sections as well with a few pieces of 1708 and some 8oz 6" tape to tie them together.

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Once the glass cures, underneath the new lip will be cut out and sanded down. One or two more layers of 1708 will go down on the underside to help secure the new lip.


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