Tell me about polyurethane foam.

[turfman]

I'm getting geared up to put a new deck in my 81 cobia 180 CC. While doing some preliminary ramblings a thought crossed my mind. " If I'm going to redo the deck, might as well redo the foam too.."

Question is; I have a supplier(mcmaster carr) for two part poly foam that's closed cell and decently priced. I asked the guy if it was coast guard approved. ( Blank stare) I'm wondering if this two part poly closed cell foam would be ok or do I have to get a marine spec.

thanks all
turfman

 

[60 grit sandpaper]

Re: Tell me about polyurethane foam.

sounds good.polyurethane products are good.Closed cell so it won't absorb moisture.Normal foam used for insulation is strong enough to walk on'but ofcorse must be covered.A 2 part poly might have a lower density,and not sutiable to lay floor on.You would have to level it after poured.Can you use the ridgid stuff?Check on the price difference too.

 

[TerryMSU]

Re: Tell me about polyurethane foam.

If you talk to the right person at McMaster-Carr, you should be able to get an answer. If nothing else, they should be able to get the manufacturers spec sheet from them.

Thanks,
TerryMSU

 

[turfman]

Re: Tell me about polyurethane foam.

On their website its page 3382. The foam comes in two canisters. The density is 1.75lbs/ft, that doesn't seem enough. But then again I don't know.

turfman

 

[wire2]

Re: Tell me about polyurethane foam.

That's the same stuff used in new cars for sound deadening and sealing. Temperature has a large effect on expansion speed.

If you spray some in a small box first, you'll get an idea of expansion rate. Then spray it into cavities in boat, place decking in place, and it will slowly expand to completely fill the void. No cutting or leveling required.

 

[60 grit sandpaper]

Re: Tell me about polyurethane foam.

In small voids- -yes but for larger areas the floor may have to be strong enough so it is not dependant on the foam for good support.

 

[Bondo]

Re: Tell me about polyurethane foam.

Tell me about polyurethane foam.

It'll hold Water,+ Rot your boat....................

 

[wire2]

Re: Tell me about polyurethane foam.

It'll hold Water,+ Rot your boat....................

Aha! So it's not closed cell then.

I dunno if they still do, but ~25 years ago Four Winns used black poly oval "balls", stacked end to end along the stringers. Seemed like a good idea then, and now.

 

[turfman]

Re: Tell me about polyurethane foam.

I thought closed cell poly foam is what boat mfg's used. If they do not; what do they use.


turfman

 

[Nova II 260]

Re: Tell me about polyurethane foam.

It'll hold Water,+ Rot your boat....................

Spot on. Don't give mold/rot a home. What do you need foam for? If you feel you must have it, foam your gunnels and super structures, not your bilge. In an swamping, your boat is ruined (repairable) with or without foam. The damage is the same.

 

[Mr Hands]

Re: Tell me about polyurethane foam.

see here for info on foam and coast guard regs:
http://www.uscomposites.com/foam.html
I used it thinking I had to comply, but I will only be on inland waters so it won't be an issue.
The way I used was in combination with lots of pop, water, bleach bottles, etc.
They are lighter and far more buoyant than foam. The foam was used to fill in all the voids and keep the bottles in place. If you go this route, be aware the bottles will float in the foam, so use very little foam to start.

 

[watermellonI]

Re: Tell me about polyurethane foam.

I ve read and read about foam or not to foam, ping pong ball soda bottle etc, and decided for me, I want something a little larger to hold onto should something happen to the boat, no foam, well it will sink. if there is foam and just in case something happens, I have something to cling to that the Coast Guard can see real good, foam will hold moisture but it takes years for it to absorb.
I just redid a boat made in 90 and all the wood was rotted but the foam was actuallly good.

 

[Tail_Gunner]

Re: Tell me about polyurethane foam.

It'll hold Water,+ Rot your boat....................

Bondo you are a master tech and give insight to repairing motor's few can do........and free i might add. But are you so sure foam could not or would not save a life, and are you so sure mfg's did not use a really inferior foam...you know corporate greed.

I am no means busting on what your contribution's are, actually i am asking you to take a very close look at what has been done, (10 yrs ago) and the new closed cell foam that is being distrubted now.

One last thing........ there are no atheist's in a fox hole or going down in the big blue drink............

 

[Maj Easy 1]

Re: Tell me about polyurethane foam.

I'm getting geared up to put a new deck in my 81 cobia 180 CC. While doing some preliminary ramblings a thought crossed my mind. " If I'm going to redo the deck, might as well redo the foam too.."

Question is; I have a supplier(mcmaster carr) for two part poly foam that's closed cell and decently priced. I asked the guy if it was coast guard approved. ( Blank stare) I'm wondering if this two part poly closed cell foam would be ok or do I have to get a marine spec.

thanks all
turfman

thanks for bringing up this topic...
for the past 10 to 15 years i had a 2 part poly foam sprayed in my cargo trailers, even had it sprayed in a couple of cargo vans..... this is same stuff they use for insulating roofs and in between studs in your home...
it never held any moisture but it was never permanently submersed either...

i always thought this was the stuff that made boston whalers unsinkable.....

 

[turfman]

Re: Tell me about polyurethane foam.

I ask this question because there is foam under my deck. The stringers are good and the foam is mostly dry; but is deteriorating. I don't know if the foam is oem or not; but its there and the boat handled fine before I tore up the deck. I'm sure there is foam in the gunwales ans possibly between the layers of the hull. I don't know if I need it or it was overdone by the previous owner thinking he doesn't want to go down in a storm or something.

But it is indeed there below the deck. So I figure why not replace it while I'm at it.

turfman

 

[Bondo]

Re: Tell me about polyurethane foam.

I used it thinking I had to comply, but I will only be on inland waters so it won't be an issue.

Ayuh,.......... You're Not an OEM,......
You have to comply with basically None of the "Rules",...........
It's Your Boat,+ you can do as you Please..........

I just redid a boat made in 90 and all the wood was rotted but the foam was actuallly good.

The Foam doesn't allow proper drainage,+ drying,........
It Rots your Boat..............

But are you so sure foam could not or would not save a life, and are you so sure mfg's did not use a really inferior foam...you know corporate greed.

Ayuh,............ Exactly..............

PFDs save Lives,...........
And,..
It helps quite Alot if somebody onboard at the time of an Incident happens to have a working brain cell or 2..........
Ya know,........ Plain ole Common Sense..............

I also don't Doubt that,....
All that mushy waterlogged Crap you guys are pulling out of these project boats,........
Was Waterproof Closed-Cell Foam when it was Installed.........

i always thought this was the stuff that made boston whalers unsinkable.....

Ayuh,...........
That's Why a shrewd Buyer of Boston Whalers always Weighs a boat before making an Offer,........
I remember a 13'er That was drilled,+ stood on end to Lighten it's load,.....
It was Wet under that boat for over 6 months,..... It never did quit Leaking,....
It was patched up,+ unloaded......

I ask this question because there is foam under my deck.So I figure why not replace it while I'm at it.
turfman

Ayuh,.......... As you can see Turfman,.........
To Foam or Not to Foam is a rather Personal Choice.................................................

 

[turfman]

Re: Tell me about polyurethane foam.

O.k That didn't help. If I can read between the lines, you're saying not to put the foam back in because it probably isn't original to the boat and will eventually rot something out.. Got it!


turfman

 

[Mr Hands]

Re: Tell me about polyurethane foam.

One of the problems my boat had was there was no drainage built in to prevent water from soaking into the old styrofoam blocks that were there. From what I read here, that seems to be a pretty common oversight by boatbuilders.
If you opt to use foam as a safety measure and/or structural reinforcement, I suggest you design in a way for water to get out. No soaking foam = no rotting.

 

[Tail_Gunner]

Re: Tell me about polyurethane foam.

Drainage is a very hard fact of life, however i for one did foam. I did put my floor down first and then poured the foam in letting the foam expand into all the nook's and cranny's and it does expand with considerable force. I drilled escape vent's for the foam to vent out hopefully there are no void's for any future water to get into....

Ohh i also used 9lb foam and my deck is as hard as a rock, and one side benefit two part foam has enourmous adhesion quality's, the deck is glued to the foam core and the core is glued to the hull like making for one very solid hull, deck combo.

 

[Nova II 260]

Re: Tell me about polyurethane foam.

Here's the manufacturing problem with 2 part foam, you don't really know until you open her up.

close up
more
I don't like foam and I don't have the answer. I like the coke bottle with sheet foam idea for sound deadning and floatation, but never used it.