Foam suggestions

[littlehero]

Hi, I've been reading on the best solution for replacement foam and there are quite a few non-iboats forums that suggest hardware store bought yellow closed cell construction foam over the two-part marine uber expensive foam.

Thoughts?

 

[Bob_VT]

Re: Foam suggestions

Yellow???? What material is the yellow? We have many that have used 2" blue board or pink board...... some have used dollar store pool noodles.

Welcome to iboats!!

 

[saildan]

Re: Foam suggestions

Hi, I've been reading on the best solution for replacement foam and there are quite a few non-iboats forums that suggest hardware store bought yellow closed cell construction foam over the two-part marine uber expensive foam.

Dow Great Stuff
home insulation foam**
12 oz can
Cost (online) $5
Contents (expanded) - 250 ft of 1/2" diameter bead (Dow Web Page)
Density - 1.5 lb / cu ft (not marine compliant)

(in round numbers)

r = 0.25
Pi * .25^2 = 0.2
250' = 3000"
3000 * 0.2 = 600 cu in
600 cu in = 1/3 cu ft
One Can = 1/3 cu ft

did I get that right​

Cost per cubic foot ~$15




US Composites uber expensive foam
http://www.uscomposites.com/foam.html
Marine Grade Urethane Foam
1.7 Qts
Cost (online) $20.50
Contents (expanded) - 2 cu ft
Density - 2 lb / cu ft (US Coast Guard Minimum Requirement***)

Cost per cubic foot ~$10.25



** GREAT STUFF? ? FAQ
http://greatstuff.dow.com/literature/index.htm

The foam does not cure properly if it is used to fill large voids unless it is put down in layers and allowed to cure before the next layer is applied. Do not use GREAT STUFF? to fill enclosed voids such as behind drywall or under tub surrounds.

*** USCG BOATBUILDER'S HANDBOOK
http://www.uscgboating.org/regulations/boatbuilder_s_handbook/flotation_part1_d.aspx

.

 

[bananaboater]

Re: Foam suggestions

I would avoid the expanding stuff. Hard to control and it finds small drainage areas needed to drain boat.

 

[littlehero]

Re: Foam suggestions

Hhhhmmm, thanks Saildan, especially the link to the USCG regs. And Bananaboater, The expanding problem is why I was looking for options. The boat is small (15'x72") and cramping the drainage would counter the whole point of replacing the deck.

All in all it's good to know I have options, thanks everyone

 

[saildan]

Re: Foam suggestions

Hhhhmmm, thanks Saildan, especially the link to the USCG regs. And Bananaboater, The expanding problem is why I was looking for options. The boat is small (15'x72") and cramping the drainage would counter the whole point of replacing the deck.

All in all it's good to know I have options, thanks everyone

It's so odd nobody has made rough molds from trash bag lined plywood for the spaces in the boat where replacement is needed, pour in 2-part marine foam, let it set, trim it up and add drain channels, glue the pieces in place with small pours of 2-part. Custom fit - solid - well draining - compliant

 

[Boater45]

Re: Foam suggestions

Or line your void with plastic......pour in two part foam......pull out your void form.....notch for drainage.....re-insert

 

[North Beach]

Re: Foam suggestions

Or don't use that crap poured in foam. Half the time it doesn't set up right and the rest of the time it causes about a hundred other problems.

Manufacturer's use this stuff cause it's easy and they want to sell you another boat in a few years.

 

[CheapboatKev]

Re: Foam suggestions

Daddy always said "Beware of Yellow foam" or was that snow?

 

[North Beach]

Re: Foam suggestions

Frank Zappa

 

[ghamby]

Re: Foam suggestions

that canned foam absorbs water and is totally non- structural.
http://www.mertons.com/Floatation/index.html

http://www.clarkcraft.com/cgi-suppl...foam&*******=69471dd48ade5b7ef9a05736711315e6

Take a look at these sites.No recommendations, just a place to start

 

[Boater45]

Re: Foam suggestions

Or don't use that crap poured in foam. Half the time it doesn't set up right and the rest of the time it causes about a hundred other problems.

Manufacturer's use this stuff cause it's easy and they want to sell you another boat in a few years.

I have to disagree on the two part foam.....it is very easy to work with and you get an outstanding result.....just follow the instructions. I like to use Polygard Hi-Bond poly-u-foam.

 

[CheapboatKev]

Re: Foam suggestions

I have to disagree on the two part foam.....it is very easy to work with and you get an outstanding result.....just follow the instructions. I like to use Polygard Hi-Bond poly-u-foam.

Have ya ever dug and scraped and cussed that stuff out of a project after sitting for a few years?

 

[ghamby]

Re: Foam suggestions

Could you apply mold release wax to the bilge surfaces prior to foaming so you
could pop out the cured foam?

 

[Boater45]

Re: Foam suggestions

Have ya ever dug and scraped and cussed that stuff out of a project after sitting for a few years?

No not really, I haven't had to pull the deck or replace a transom from any boat I have ever built. Best way to get around that is to make them so that they don't leak!

 

[North Beach]

Re: Foam suggestions

I have to disagree on the two part foam.....it is very easy to work with and you get an outstanding result.....just follow the instructions. I like to use Polygard Hi-Bond poly-u-foam.

Here's what I don't understand. why would you use something that's so danged hard to remove? and something that's so dependent upon field mixing/install proceedures when you can purchase extruded polystyrene from a big box store that was manufactured under ideal manufacturing conditions that you can just cut, lay in and it will allow the water to move around it and drain to where it's supposed to drain to?

Just because something is touted as the latest, greatest thing since sliced bread doesn't necessarily make it so. And I'm sure all the boat manufacturer's jumped on the poured in place. Whole lot easear to ship and store a few cans of crap than those big sheets of insulation.

Now maybe we're talking fiberglass vs tin here and the problems I'm experiencing with my 89 Mariner won't present themselves in your glass construction. But I can say that the expanded polystyrenes won't absorb moisture and the poured in place (I assume open celled) foam I took out of my Starcraft was thoroughly saturated. From my experience working with the various foam insulations in the roof consulting end of things, we know that expanded and two part mixed foams absorb moisture at a very high rate when exposed to high temps. That's not something I want in the bilge of any boat I'm tryin to cross the bay in.

Plus it looks like all the areas where the foam mixure ratio wasn't perfect, the chemicals ate the aluminum. Not good!

 

[jasoutside]

Re: Foam suggestions

 

[Boater45]

Re: Foam suggestions

To each his own!!! I prefer two part foam some don't. I have never had any problem with it and I don't buy manufactured boats.

 

[North Beach]

Re: Foam suggestions

Boater 45, the problem is boats get hot and bilges get wet. The name of the game here is to get the wet out of the hot. How many years have these boats been getting serious usage out in the elements?

I'd like to know how long these boats you've been getting these great results out of have been in serious service. See, I can pour foam in a boat and next week say it works just great, but I'm working on an 89 aluminum boat that had poured in foam and it caused a lot of problems. There are several in the restore forums that exhibit the same issues. There are lots of boats in the restore forums that have water soaked poured in place and we should learn from that.

We need to look at forensic history here.

 

[Boater45]

Re: Foam suggestions

Oh yeah....another reason to use a two part marine foam is that it meets the US Coast Guard flotation requirements. I don't think pool noodles do. Here is the Coast Guard link: http://ecfr.gpoaccess.gov/cgi/t/tex...iew=text;node=33:2.0.1.8.45.6;idno=33;cc=ecfr