Who's done a no foam refoam?

[SJBrit]

what ever happend to the ping pong balls idea.. ??

I think the trouble with that is that spheres only fill about half the available volume:

Sphere volume = 4/3 pi r^3
Cube volume that fits around the sphere = (2r)^3

The % volume filled by the sphere is therefore (4/3 pi)/8 which is about 50%.

 

[GDFL]

You're killing the environment. If you do it, then I'm going straight to AlGore. You had better be planning on buying some carbon offsets for this project. I can sell you what you need, but it won't be cheap. Carbon offsets for polystyrene foam are outrageous even if I give you a discount.

 

[GDFL]

I think the trouble with that is that spheres only fill about half the available volume:

Sphere volume = 4/3 pi r^3
Cube volume that fits around the sphere = (2r)^3

The % volume filled by the sphere is therefore (4/3 pi)/8 which is about 50%.

So what is your % fill after cutting to go around all the crap in the tray like the tubes and inserts and pump tunnel? :hitwithrock:

Do it if you want. You're right. It's cheap and easy. It's just :deadhorse:

 

[Matt_E]

Did you add layers of glass to the sides or tray as well

Oh yea.

 

[Matt_E]

I disagree. The poured in foam provides "some" structure. The polystyrene sheets will provide none so essentially you'll have equal structural strength whether you have sheets of foam in there or not. Your reinforcement more than makes up for any losses of removing the poured foam. Has anyone here or even your sister's friend's boyfriend's cousin ever heard of a catastrophic failure in the tray area? Not to my knowledge. Sure they crack (minimal chance after reinforced), but the cracks are never to such a degree that water comes flooding in at a rapid rate.

Put small drains in the back and run no foam or upper foam only. The water is going to get in there in small amounts whether you have sheets of foam in there or not. For the sheets to really be effective anyway in the extremely rare catastrophic failure scenario, you'd have to have enough sheet foam to displace virtually 100% of the tray cavity volume to keep it from sinking.

I think the sheet foam makes people feel good, but in actuality if you took an axe to the side of your tray for some reason, it would sink either way. I think the real worst case scenario for an average rider is that you get a crack under your bondline (very unlikely after reinforcing) and you get a slow trickle of water in there. It won't be enough to count unless you somehow were riding 10 hours straight without beaching to refuel and use the little drains you should put in to get what little water is in there out. If you were the lucky guy that somehow ended up with a massive hole in the rear of your ski while the engine simultaneously died, then the sheet foam you add will likely only slow the rate of decent to the bottom of the lake and make it drift around and harder to find later.

That's just my 2 cents.

My bulkhead separated from the bottom of the hull. I had about 1/2-3/4 gallon of water pour out after every ride, and I suspect that's as much voidspace as was available in the back.

So, I disagree with what you're saying. :arms:





(You're mostly right though)

 

[Rickster]

I did the same as Matt E, and have never looked back....

Styrofoam in the bottom, two part foam in the top, and drain plugs in the rear. I ran two layers of 1708 biax in the tray and up the sides...

It is light, the water drains out, and it was positively bouyant in Daytona when I sunk it.:dunce:

And I disagree about he styrofoam not giving structural integrity to the tray...

:27:

 

[the WaTeRhAwK]

just install air bladders and valve stems. fill them with helium.

 

[Dustin Mustangs]

I think the trouble with that is that spheres only fill about half the available volume:

Sphere volume = 4/3 pi r^3
Cube volume that fits around the sphere = (2r)^3

The % volume filled by the sphere is therefore (4/3 pi)/8 which is about 50%.

This is wrong. The "cubes" would overlap each other unless the balls are very carefully arranged. Realistically you'd be over 60% and potentially as high as 75%.

 

[SJBrit]

This is wrong. The "cubes" would overlap each other unless the balls are very carefully arranged. Realistically you'd be over 60% and potentially as high as 75%.

In practice you are correct. But I am wrong twice, because the spheres would pack hexagonally and that would put the fill % up more too. My over-all point was that ping pong balls would not be that efficient at filling the space, which is true compared to 2-part foam. Compared to polystyrene, I guess it depends on how much time you want to spend getting all the voids filled.

I like the helium idea best, although it could slow down rotation for backflips because all the lift is at the back of the ski. Front flip anyone...? :sneaky: Would make for great nose stabs too.

 

[SJBrit]

:deadhorse:

You have no idea how much pleasure that smiley gives me. I may go down to the barn and beat a horse right now.... :fing02:

 

[Big Kahuna]

Or the guy that does the odd jobs like fixing a water spigot!

 

[SJBrit]

Or the guy that does the odd jobs like fixing a water spigot!

He's already buried in the north pasture....

 

[Big Kahuna]

LOL
still cannot believe you got REV footholds. Ick.

 

[SJBrit]

LOL
still cannot believe you got REV footholds. Ick.

We'll see. They're cheap, so I'm not to worried if I don't like them when they arrive.

 

[GDFL]

LOL
still cannot believe you got REV footholds. Ick.

You're forgetting that he fell off the face of the earth for over a year and isn't quite up to speed on what all the cool kids are doing these days. He's a bit old school :dunce:

 

[McDog]

Polystyrene adds almost no weight. It saves the environment because it is sealed up in a jetski hull away from the environment. Ha Ha. Filling the upper gunwhales with pour in foam and locking the other polystyrene in place with some more 2 part will retain the structural integrity and still allow water to drain out with some plugs. Best of all worlds.

 

[SJBrit]

You're forgetting that he fell off the face of the earth for over a year and isn't quite up to speed on what all the cool kids are doing these days. He's a bit old school :dunce:

There's no school like it! :arms:

The only reason I want to replace my footholds is for more padding - I like everything about the ones I have except they don't leave enough room for a 25mm pad.

I looked for footholds for a long time, and pretty much decided just to build my own. That's a pain to do from scratch though, so I was going to hack my old Kickers around, except they are not very hackable. The REVs are cheap, close to what I want, and eminently hackable.

I'm not really a bandwagon kinda guy....

 

[SJBrit]

So, which drain plugs are you foam free types running?

 

[Matt_E]

Some generic plugs I got from Overtons.

 

[GDFL]

I've seen anything from stainless sheet metal screws and an o-ring to stock yamaha drain plugs from couches. You could affix some sort of plastic or metal backing inside the hull and tap it for a bolt of your choice too.