Great Stuff for flotaion

[T.S.Davis]

Why would you use that stuff when they make 2 part polyurethane foam for exactly this purpose. They use it for real boats. Lighter and lot's stronger than the spray.

Either one will expand and shrink with temp change. So you leave it out in the sun too long one day and it cracks a seem OR it doesn't crack the seem but when it cools down it warps the hull. Been there done that. Yes, I've tried it all and don't use expanding foam anymore. That's how my whip made it to 9.5 pounds.

Pool noodles or blue foam for me. I've made sponson out of some stuff callled sign foam too. I think that's urethane. Crazy park your car on it strong.

[steve-b]

" if done right" hmmm, Lets call NASA.

[Doby]

" if done right" hmmm, Lets call NASA.

Hmmm,,lets read instructions.

[T.S.Davis]

Well, I used the right product in my first Whip. 2 part pour in. With that boat I won an IMPBA National title, a Michigan Cup, an MMEU club points championship, took second at the NAMBA nats, and set a 2 lap oval record.

When I built the replacement boat I didn't put the foam in it. I really don't think the weight is worth it. We'll see how it fairs in traffic. It's undefeated so far though.

My whole new fleet went pour foam free this season. For what that's worth.

[D. Newland]

I just got done cutting the entire top off of a Viper to clean out a Great Stuff job I did 18 months ago. It did not adhere very well and it's not that strong (as far as reinforcing the hull).

This is the 2 part foam that's been mentioned. It's not that expensive. It's a way better product, way easier to handle/manipulate, stronger and it's made for marine use.

I used 3-4 ounces per side for a 33" mono, then 2 ounces in the nose when the sides set up.
As mentioned, you will get some added weight with it, so use pool noodle if that's a concern.

http://www.uscomposites.com/foam.html

[T.S.Davis]

yep That's the exact stuff I used.

Be careful Dave. If it get's hot it will expand and then when it cools it will suck the deck with it. I've had it suck the ride pads out of shape on a Viper. Super strong though. I've got it in a scale boat that I can actually stand on the deck.

[Gary]

I always put my boats on the scale. My boat is 9lbs 13oz always ..give or take an ounce or two and has been upside down more times than not LOL Foam absorbing water never seem to bother it at all so i think it did not absorb anything.

[Rumdog]

I filled the entire sponsons on a 1/8 scale proboat ms. Elam with greatstuff. 0 problems. as long as there is somewhere for the foam to go when it expands, your fine. It does not expand a lot. Cures quite firm and does NOT absorb water. My hull is MUCH more rigid and will not sink. Read the directions, you cant go wrong that way. Also, how much does foam weigh? Really? When I filled my UL-1 sponsons, the weight of that foam was probably no more than the weight of a r/x pack, if that.

[m4a1usr]

I would love to see someone shoot an amount, let it cure fully, weight it, submerge it in water for 24-48 hours, and then weight it again...

THAT will tell you if it absorbs water..... Enquiring minds want to know

Later
Mike

Its not that the foam itself absorbs water. Its closed cell. I doubt it does myself. But what it does do is semi seal off areas of your hull where water can seep around and no air can circulate to dry that area out. When you pour or spray any of our prefered non expanding foam it doesnt glue itself to all the edges it touches. It might appear so but water, as many of you guys know with our issues with electronics, magically or not so magically, finds its water thru either in a vapor state or liquid. If theres a place for it to reside deep inside your hull its there whether you want to admit it or not. There doesnt have to be a problem if you have some stuck up front in the sponsons or where ever. The amount is most likely minimal. Its a Ford/Chevy thing. You like pool noodles use them. You like non expanding foam use it. I have both in my hulls. The hulls where I cannot gain access get foam. The ones where I can get a combo of blue board and noodles.

John

[Raydee]

I have seen Pool noodles come out of a boat, I think the Great stuff will stick mush better. I will weigh my Hatch and then put it in water overnight and weigh it again in the morning.

[Brushless55]

I'm not sure about anyone else, but when one of my boats flips, I'm not one to let it set upside down in the lake over night and into the next day or so, say like 24-48hrs!

and I always (pool noodles or spray foam), take the cowl off and set the hull in the sun to dry for a few before I take it out again..
and the cowl never stays on my boats when I bring them home from the lake
I dry everything out very well..

[T.S.Davis]

How much does foam weigh? Well, my foam filled Whip 20 was 9.5 something pounds and the new Whip 20 without the foam is 5 pounds on the button. So I guess in a 30 ish inch long boat about 4.5 pounds or very close to twice as much as a boat without it.

Foam it up if you want but I'm not going back. I gotta go fast. It's like heroin.

[Brushless55]

How much does foam weigh? Well, my foam filled Whip 20 was 9.5 something pounds and the new Whip 20 without the foam is 5 pounds on the button. So I guess in a 30 ish inch long boat about 4.5 pounds or very close to twice as much as a boat without it.

Foam it up if you want but I'm not going back. I gotta go fast. It's like heroin.

How in the world is this possible?
the can its self is only 16oz
lets see, each can holds 12oz so that would be 6 cans of foam?
I use this in all my boats and I think I added 2 to 4oz of weight

[T.S.Davis]

I just noticed something. This thread has 4 world/national record holders saying "don't use great stuff" and still some just gotta be right. Stubborn buggers yous's. haha

[Rumdog]

Hmm. Does the foam gain weight as it expands? I know a full can of Greatstuff no way weighs 4.5lbs. Not sure how it could possibly weigh more once expanded.