Extremely disapointed in US Composites foam!

[Waternut]

I bought 3lb expanding foam from US composites and defoamed my entire ski over the winter. Figuring I couldn't seal the ski perfectly, I decided to install drains. Well a month ago I put it in the water for the first time and lightly rode it while breaking in the engine but the back end stayed in the water for about 2 hours total. Then when I got home and pulled the drain plugs and some water dribbled out. I continued the break in process last weekend (3 weeks later) and did roughly the same thing but rode a little more aggressively. Today, (4 weeks after initial water test) I rode for about 15 minutes and the ski was in the water for 30 minutes.

Here's the crappy part: I noticed the sealant around my scupper was gone so I pried it off to refit and reseal it. Seeing the amount of water sitting where the scupper used to be had me concerned about the foam. So far I've dug out 6-8 inches deep and 3 inches up and it's completely soaked like a sponge! :261: Less than a month of minimal water entrapment and less than 5 hours of ride time and the foam is waterlogged. :aargh4:

How is that closed cell foam?!?! I should've just used newspaper. The whole reason I bought the 3lb foam over the 2lb was because the 2lb was supposedly 3-5% open cell foam and the 3lb was supposed to be 100% closed cell. Great Stuff holds out water better than that!! :soapbox:

 

[ADDict]

Dang man that sucks. Unfortunately I bet mine is the same way.

 

[Matt_E]

It ain't closed cell foam. :biggrin:

 

[stanton]

who told you it was closed cell? lol

 

[Ericfox]

yeah... but isnt it only supposed to absorb like only a very small amount of water per year?

 

[Shonuff]

Dude, go get some Kawasaki styrofoam and fill it all in.

 

[Big Kahuna]

uh, sounds like your seals where your drains were leaking, what about around your footholds and plumbing at the bulkhead.

Regardless about the foam being saturated. If no water was leaking in (must be a big leak to have that much water in there as it is) then wet foam would not be an issue.

 

[Matt_E]

yeah... but isnt it only supposed to absorb like only a very small amount of water per year?

No. It sucks it up like a sponge.

 

[Ericfox]

really? thats weird... I thought it was water resistant... like it would break-down and soak up water over time...

Guess next time I do foam I will be doing the dow foam... dang.... hope Pauls ski will be water free for a while! We tried to seal it up... but we used 3lb 2 part foam...

 

[Waternut]

No. It sucks it up like a sponge.

Then why is everyone using it? Everyone talks about it like it's the greatest stuff ever and the whole point of using US composites expensive foam over great stuff or any other random cheap foam from walmart was because it was water resistant. Obviously it can't be water proof but the site indicates, "This foam is approximately 95-98% closed cell which resists absorbing water, however continuous water submersion can eventually lead to loss of buoyancy over a period of years." ....YEARS!!! not days.

 

[keefer]

Dude, go get some Kawasaki styrofoam and fill it all in.

I have used some planks of polyproplene true closed cell foam that I carved up to fit. This is the same type of foam that the insert in the front of a SJ is made of. It is light and takes up space in the bottom so you don't use so much pour in foam.

 

[Matt_E]

Everyone talks about it like it's the greatest stuff ever

Who is? :biggrin:


People use it because it's convenient and easy to apply.

 

[Waternut]

Dude, go get some Kawasaki styrofoam and fill it all in.

Where can you get that stuff? My 750 was wide open to water for a while and that foam was dry as a bone after I vacuumed up the standing water and let it sit for a couple days.

 

[Matt_E]

Any bigger hardware store will have sheets of building insulation foam - extruded polystyrene.

They cost about $5 bucks. You carve it up into pieces that fit.
Check out my build thread for details

 

[Speedfreak]

Just use great stuff foam and when the water gets in which it will it drains right back out. It is only needed for a tempoary folation. If you sank your ski and it was under water for a month then that foam is what you need. But for 10 minutes or so I still say GreatStuff is great stuff.

 

[butti]

if you tried to foam a whole ski with great stuff it wouldnt be cheap either

 

[Waternut]

Well I guess it's a live and learn process and various people recommended polystyrene squares because it was lighter but no one said use it because expanding foam absorbs water.

One question that continues to boggle my mind though... Why does everyone defoam their ski if they're just going to put a foam back in that will reabsorb the water faster than stock foam?

 

[Matt_E]

Well I guess it's a live and learn process and various people recommended polystyrene squares because it was lighter but no one said use it because expanding foam absorbs water.

Who said that?

The ONLY reason people use polystyrene is precisely because it doesn't absorb water.
It's harder to work with, though.

 

[Kennay]

Well I guess it's a live and learn process and various people recommended polystyrene squares because it was lighter but no one said use it because expanding foam absorbs water.

One question that continues to boggle my mind though... Why does everyone defoam their ski if they're just going to put a foam back in that will reabsorb the water faster than stock foam?

Making you ski watertight isn't exactly rocket science. If it's watertight. it won't matter if you used an actual sponge. It's going to stay dry.

 

[Waternut]

Not sure how to make a ski waterproof... I tried to use at least 2-3 layers of fiberglass cloth and resin on all non factory seams, 4-6 layers of paint, and seal up both sides of every plumbing connection with 5200. I'm sure there were areas that I messed up but lets face it...liquid has a fantastic way of finding even the smallest pin hole.

I don't mean to be bitter but since there are countless threads about using expanding foam, I'm obviously not alone in thinking that this stuff is fairly resilient to water. Just wanted to ensure that people are aware that this stuff is not even close to waterproof.