Expanding foam??????

[Doug Smock]

I wish I had a dollar for every time I see a post on expandable foam.

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

The heavier the foam the stronger. But remember it does make the hull heavier. It comes in useful for when you have too light of a hull like one of my 1/8th scales. You don't need alot of it either. It does not absorb water. I have used the 2 and 4# mixes. Oh and make sure you use it where you want it because it is a bear to get back out. Dremeling nightmare. This stuff does not keep expanding like some can brands do.

I have used it several times and it works great. Follow the instructions and work fast!

Doug

[HOTWATER]

lol! I was just thinking about your Rico (and the two part foam you used in it) as I was reading this! Too funny!

[monojeff]

No it doesn't.

Well from my experience & from other threads I have read elsewhere it DOES!

I used the large gap great stuff on a mono I was building before I put on the deck and then put water in the boat. Let is sit for a few minutes then tipped over the boat and squeezed the foam some. It DID absorb water so I took it out.

Not trying to argue about just just saying from my experience it did.

[LiPo Power]

What is wrong with swimming pool noodle????
They are cheep too !!!

[jcald2000]

Don't use Great Stuff in any flavor it is a humidty cure product!
Use the 2 part foam.

[HOTWATER]

I wish I had a dollar for every time I see a post on expandable foam.

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

The heavier the foam the stronger. But remember it does make the hull heavier. It comes in useful for when you have too light of a hull like one of my 1/8th scales. You don't need alot of it either. It does not absorb water. I have used the 2 and 4# mixes. Oh and make sure you use it where you want it becouse it is a bear to get back out. Dremeling nightmare. This stuff does not keep expanding like some can brands do.

Thanks for the link Alan...I'll be putting this on my shopping supplies list....

-Kent

[dano1]

Thanks for the advice gang, very helpful as usual, ok.....what the heck is pool noodles? sorry, have no clue what this is and to lazy to google it...ha ha, love the inputs anyways, dont get that from google!!

[m4a1usr]

I've tried great stuff but it absorbs water A LOT of it!

I think what you meant to say is it traps water. Not absorbs it. And you are correct. It does allow moisture to remain trapped behind it. Since expanding foam does not move symmetrically it allows gaps and open areas to form where moisture can remain as natural convection does not allow for water to escape.

If you come from the nitro/gas world of boating (much longer history of do's and donts) its well known to not to use expanding foam in single pour applications. If I can find the links I will post them. I do like to use non expanding foam in certain hull builds but its got certain implications users should be aware of. And trapping moisture inside is not a myth.

John

[HOTWATER]

This is from the USCOMPOSITES site (2 part Urethane Pour Foam)......

"This two-part liquid, expanding rigid urethane foam is a closed cell, pourable foam, which will resist the absorption of water."

...Sounds good to me!

Oh yeah....Pool Noodles....Here you go dano1....

---> http://en.wikipedia.org/wiki/Pool_noodle

[LarrysDrifter]

Heres my thought.Everyones opinions are very valuable.I say try something once.If you dont like it dont do it again.I was always afraid of expanding foam(Great Stuff),then I heard the window and door doesnt expand as much as the regular-so I tried it.And I like it.Its cheap,can be bought locally and if you take your time,all will be well.
As far as trapping water-Im sure it does.I used G.S. in my Triple Cat with great results.I also let it cure fully then sealed it with epoxy.Now it shouldnt trap water or even touch water.
Pool noodles do hold water.This coming summer,sit on one or just play with one in general the pool.Then after its been wet for any amount of time,you can literally wring the water out of them.

[HOTWATER]

I wish I had a dollar for every time I see a post on expandable foam.

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

The heavier the foam the stronger. But remember it does make the hull heavier. It comes in useful for when you have too light of a hull like one of my 1/8th scales. You don't need alot of it either. It does not absorb water. I have used the 2 and 4# mixes. Oh and make sure you use it where you want it becouse it is a bear to get back out. Dremeling nightmare. This stuff does not keep expanding like some can brands do.

What is better to use in my 31" mono...2# or 4# mixes? also, i'm looking at 1/2 gallon kits...how much do I need to use/mix of that to use in the nose of my mono hull?

Thanks!

-Kent

[D. Newland]

How much of the nose do you want to fill?

Use the 2 lb stuff.

Maybe start with 2 oz each (4 oz total), mix fast and dump right into the nose. Point nose downward and move it around as it starts to expand to make sure it's laying down as evenly as possible.

It will end up looking like the photo on the composite site, specifically the top of the foam. When expanded, it will be rounded. You can then mix up another 2 oz's (total) and pour it into the cracks/crevacies that are left behind (between the original foam job and the hull) to help even out the job.

To get a good feel of it, mix thoroughly 1 oz each part and pour into a plastic cup or a milk jug w/the top cut off. This will give you an idea on it's expansion rate, and how fast you have to work w/the stuff.

[Jesse J]

I just used some 4# in my super light Cyklon and it is as solid as a rock!! I would like to experiment with lighter stuff, but really like the density. I also used it in my balsa cat - sandable and very rigid. I had a crooked frame, straightened it on the building board, filled up the framing with 4# and now it is super straight and true. I could use it as a weapon now.

So my $0.02: if you have a strong hull and just want some flotation - 2# or less
if you want to rigid up an abs or super light fg/gell coat hull then probably 4# (would like to try 3# and 2# just to see. My buddy and I were even thinking we could make a plug with this 4#, glass it and call it done!

[Jesse J]

yep fast and have the place/product over 75deg F. you get about 20 seconds to mix and 30 seconds to pour. then don't touch for 20 minutes and violla - solid, ready for next layer.

[dasboata]

I use the 8lb USCOMPOSITES site 2 part Urethane Pour Foam . In my mean machine I used 1OZ of each for both sponson tips I also heat the boat with a hair dryer and heat the foam to help it expand I have had for the most part good luck But I have had a seam open just a little and some sucking down on the sponson tips but it will deffently add strength