spray foam?

[kevinpratt823]

Why would it be recommended to not use spray foam inside a hull, but only the 2 part epoxy foam(such as in the UL-1 modifications thread) Is it simply because there is no accurate way to measure the ammounts going into each side or is there some other reason?

[siberianhusky]

Over expansion with the spray foam, not sure how come the other stuff doesn't do the same thing. I've used spray foam before but it was just kind of a blob, didn't put enough in the fill the void in the nose of a mono.
That being said I'd personally never foam a hull again, if you ever have to repair a foamed hull you'll know why. What a mess!
Pool noodles or chunks of foam for floatation for me. Fiberglass of carbon if I have to reinforce. Still finding bits of ground up foam in that one boat a couple years later. I have no idea where it keeps coming from, I've rinsed that hull out a few times trying to stop it.
Some people also claim the expanding foam absorbs water over time, no idea, no long term results from my experience, I'm just passing along something I've read a couple times. Seems odd that closed cell foam absorbs water but I don't know and I've never used the expensive 2 part stuff.

[Jason4636]

Don't use the spray can foam, its open cell foam and will absorb water and start to smell funky and mold. Buy the 2 part foam and make sure its closed cell foam. Kintec sell it, stuff works great. It's closed cell foam, and it will not absorb water. But it will be a P.I.T.A. if you need to do any kind of hull repair. If you have a hull that is like the Motley Crew hull where they're is a tub inside, it works great in it. But I agree with the post above me. If you can use pool noodles, use them. If your hull is weak, reinforce it with FC or CF.

[Flying Scotsman]

All the above replies are on the button.

Douggie

[Jersey Crewmax]

Where do you guys find pool noodles this time of year?

[kevinpratt823]

Thanks for the input, guys, I will heed the advice and order some up. I was surprised not to find it on OSE Parts.

[Jason4636]

Looking for pool noddles if you can't find any left over at store like wal-mart from the summer. You can order them from pool supply places, just do a search. If all else fails, get you some PVC pipe insulation foam

On the 2 part foam, I know on the MC I did, I had ordered 3 sets of foam from kintec. I used about 2 to 2 1/2. Just mix 50/50.
Mix it up in small batches, and pour in the hull. If you have a way to heat the hull up right before and during the time the foam if setting up. The faster the foam will expand, plus the bubbles will be bigger and fill the area better. Just make small pours. What hull are you trying to fill? Is it like the MC with a tub? Or is it an open hull?

[Doby]

I've seen pool noodles make it back to shore....not always the boats though....been using low expansion "Great Stuff" in 17 boats so far, never any issues as long as you know how tho use it..adds flotation and strength with little to no weight and DOES NOT ABSORB WATER.

[tlandauer]

+1 on the stuff Kintec sells.
I do however have a boat I bought from a guy who spray foamed the entire front . ( Pursuit mono) He used something like the "GREAT STUFF" from Home Depot. I asked him why he did it and he was so sure that that stuff did not absorb water. He said he sprayed some blob and put it in a swimming pool for a few days and no water was absorbed. I have no evidence to proof him wrong so far. The problem with this like Siberianhusky said is that you can not reach far enough due to the length of the spray tube and the physical size of the can being in your way.
I do have a question, what do you guys mean by "close cell/open cell foam"? On the stuff from my Pursuit, the cured foam was smooth and very hard, had no surface holes whereas actually the Kintec 2-part foam has surface holes and is softer to the touch . I used that to repair my MG and found that if I poke it hard enough I can collaps the foam somewhat.

[kevinpratt823]

Ordered a couple kits from Kintec. I am using this for the front end of my UL-1. I put "Great Stuff inside the hull of my Impulse, and a bit in my Stiletto(more so to seal the leaks in the Stiletto), I have not seen any adverse effects yet.........

[JimClark]

I believe this type of foam has an expiration date plus you woudl want to repackage it in smaller quantities. I wouldn't blame Steve for not carrying it it would be a pain in the you know what. Plus plenty of places sell it.

[tlandauer]

I believe this type of foam has an expiration date plus you woudl want to repackage it in smaller quantities. I wouldn't blame Steve for not carrying it it would be a pain in the you know what. Plus plenty of places sell it.

I believe you are absolutely right! As I said, mine was weak/soft and "holy", I wondered if I kept it too long on my shelf? It was not willing to adhere to the hull either, second batch I put was way better, but that was more recent order from Kintec.

[96XP]

I'm considering doing this inside the sponsons on my own boat at some time. If/when, I will document the process.
With a 20 year background as prop maker in film and commercial installations (sculpting mold making and air brushing)
there are options when working with polyurethane foam. It will expand with great pressure, sometimes uncontrollable till it's too late, however if you want to experiment with a lighter friendlier version, A+B components are more controllable than the foam that comes in a prepackaged canister and some of you probably have some A/B in stock.
-Try adding a few drops of water when mixing your foam components in a Dixie cup. You can cause it to expand multiple times and create less pressure in the process, resulting in a lighter foam with less damage in the expansion phase. (same goes for the spungy type foam blends used in upholstery making)
Just place the two measured parts in a cup (start small, very small) and add 3, or 4, or 5, or 6 etc... drops/water, then hand blend your mix. It will 'kick off' faster. If using larger batches in winter conditions, pre-heat the two parts in separate containers in an old microwave oven for a few short seconds. You'll need to experiment with the ratios and measure the results to get a better feel of how the mix will work in a specific application.
The exposed end (if there is) can be sealed off with a thin layer of body filler or other if required.
There are various creative applications for the above, as well making it a good shortcut for quick crude impressions.
Attached are large sculptures I made (backing my claim to experience).

100_3078.JPG

Q68X.jpg

CUPCAKE3.jpg

iron_maiden.jpg

[tlandauer]

Wow! They look fantastic!
When you add water in the mix, I wonder if that water or moisture is then trapped in the foam? Just curious. I have no chemistry back ground, so please excuse my total ignorance!

[96XP]

Wow! They look fantastic!
When you add water in the mix, I wonder if that water or moisture is then trapped in the foam? Just curious. I have no chemistry back ground, so please excuse my total ignorance!

If the mix has just been injected, yes, there will still be whatever water you used in that blend. However, considering it only takes a few drops (which is barely nothing) a day in the sun or in front of a fan would pull that moisture back out as it is not a solid (locking) cell in this state. You can still apply glass resin over it or to brush it on as well for a tougher exterior with some penetration. Mixing in glass sphere (in the A/B mix) will create a more rigid result, and that is useful in some instances.