"fiberglass over Styrofoam" | SouthernPaddler.com

"fiberglass over Styrofoam"

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oldsparkey

Well-Known Member
Aug 25, 2003
10,479
123
Central , Florida
www.southernpaddler.com
Here is an interesting idea for a really light weight Pirogue and one that would never sink when flooded. :D

Been chatting about some wild ways to make a boat on the back channels and one person brought this up.... Not just an idea but an actual boat.

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Here is a short explanation of what he did..................

"fiberglass over Styrofoam".

At one time I designed a Gothic boat for an art student. Basically it was a coffin, "Moby Dick" ring a bell? Epoxy resin will adhere to but not dissolve Styrofoam. So a coffin was built from 3/4" Styrofoam and glassed. Oh yes, half the lid opened to create a cockpit. Handles down the sides of course. Surf boards have a foam core and are very strong. So why not a boat. Should be a very light boat. Styrofoam blocks can easily be carved. So, if you had a large enough piece you could sculpt the entire boat. Not a wooden boat but you could build shapes not easily attained in plywood.

Does that get your grey matter churning???????????

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Hummmmmmmmm.... Get a 16 foot by 30 inch chunk of Styrofoam , do some carving like you would do with a Cypress log to make a boat from it. Then cover it inside and outside with glass and epoxy.

Chuck.........
 
J

JEM

Well-Known Member
Dec 27, 2003
2,467
1
54
Greensboro, North Kacalacky
jemwatercraft.com
The biggest issue with foam sandwich hull (fiberglass skins over foam core) is building up puncture resistance. By the time you get the fiberglass skin strong enough, the hull weight surpasses wood or wood composite. Surf boards use around 2 pound density foam and the thinnest are about 1". Great info here: http://www.flyingfoam.com/FoamTypes.html

EPS foam doesn't bend very well. It snaps WAYYYY sooner than plywood or timber. The types of foam that will bend are expensive and they tend to be floppy and bend too much requiring a more complex jig to build off of. But like Chuckles said: If you have a big enough chunk, it could work. Lots of scrap, though.

As boats getting bigger, the benefit of foam core grows because bigger boats need thicker hulls to withstand increased stress. At a certain point, a foam core hull with sufficient strength for safe operations becomes lighter than a wood cored boat. I know the theory but not specifics. I do know foam core starts to make more sense (from a hull weight perspective) on hulls over 28'.

Wenonah uses some foam in their hulls for each stiffness: http://www.wenonah.com/craftsmanship/composite_canoes_structure.php

But note it's not 100% foam core.

It certainly can be done. But I think mother nature provides the best core material. :D
 
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tx river rat

Well-Known Member
Feb 23, 2007
3,043
2
Waco Tx
They have been building aircraft from foam for a lot of years, Lets see I think it was k r rand
it can be done. they use them in the bigger 6 man boats in the yokon race and the Texas water safaria.
I am probably going to build a 16 fter for that light boat competion on another forum
Ron
 
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beekeeper

Well-Known Member
Mar 4, 2009
1,917
59
If I don't have a big block (dug-out construction), can I use sheets and do a "plank build"? I like the traditional chine log construction. Would ring nails hold or would I have to use screws? Does anybody know the mix ratio of styrofoam peanuts to epoxy needed to glue the joints together?:wink:
Lots of possibilities a thinking person could come up with. :roll:

beekeeper
PS I'm jokeing, but I bet someone can do it.
 
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oldsparkey

Well-Known Member
Aug 25, 2003
10,479
123
Central , Florida
www.southernpaddler.com
Looks like the biggest problem would be finding a chunk of the Styrofoam large enough to be used for carving out and shaping. Then as Matt said and I was thinking the same thing .... You sure would be filling some large garbage bags with the refuse of the carving and shaping.
The upside is it sure would be easier then the Cypress log Friend Keith and seedtick carved out to make that one pirogue but it would weigh a lot less. :D
 
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tx river rat

Well-Known Member
Feb 23, 2007
3,043
2
Waco Tx
In the builds I have followed they used guerrilla glue for the joints and the blue foam sheets 3/4 thick. I think on mine there will be some strips of wood 1/8 thick turned on edge in some strategics points.
Ron
 
S

seedtick

Well-Known Member
Jul 22, 2006
1,161
7
Denham Springs, LA
seems like i remember Oyster doing something similar - maybe using coated foam as a deck, on another forum

he's done a bunch of outside the normal box stuff

might want to ring him up, if he's not on hurricane watch
 
L

lil'moe

Active Member
Jan 8, 2009
38
0
Lapland, IA
Back in about 78 or 79, I bought a used "Sunfish" sailboat that was styrofoam covered with ABS plastic. It had a molded centerboard well. a piece of ply on the transom for the tiller and a piece up front for a bow cleat. It saw a lot of use for several years, then went to shed. Later, I traded a single shot .22 for another that was just styrofoam. Alas, it has never been in the water. I think fiberglas would be much stronger than the plastic, and probably work out well.
 
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Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
171
87
Okemos / East Lansing Michigan
I sailed a Sunfish in Okinawa. As I remember, if you get it going good in a broad reach, and kick the tiller over hard, the nose would dive.

My wife never could figure out why she kept getting washed overboard. "Darned controls seem to have stuck here. I'll get it fixed; climb back on."
 
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beekeeper

Well-Known Member
Mar 4, 2009
1,917
59
Will styrofoam used for house construction work, or we talking another form of foam?

beekeeper
 
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