Styrofoam

[werwer6969]

I'm interested in building a boat out of rigid styrofoam and covering it in fiberglass. I was wondering if anyone can tell me if this would work or will the fiberglass eat away at the styrofoam, any help anyone can give me would be greatly appreciated.

Greg

[SamSam]

Fiberglass won't bother it but polyester resin will melt it. Epoxy resin will work. Sam

[frosh]

Greg, there have been a number of threads in the past about the compatibility of resins and styrofoam. Ditto about the structural qualities of styrofoam and other core materials Ditto again about the water penetration issues of the various foam materials.
Suggest you research them yourself, and you will answer your own question.

[Ike]

plus all that, and penetration by gasoline, other petroleum product, and alot of cleaners, will dissolve styrofoam. You would be better off using polyurethane foams, They are resistant to gas, oils and solvent, as well as resins.

[JR-Shine]

Polyurethane foam makes for a very poor hull core also, mainly due to its peel and shear strength (or lack thereof). Low density PU can be used for insulation and flotation or as a “form” over which you laminate fiberglass. This is not the same a core it does too participate in the structure - it just takes up space. Higher density PU foam is OK for areas of high compression like a transom.

PVC foam (Divinycell and the like) are what you need for a hull core, or Corecell. I know the DIAB site (maker of divinycell) has a page on how to build a boat by strip planking a jib with foam, then glassing

Their site is www.diabgroup.com

Good Luck,

Joel

[werwer6969]

Thanks to everyone for there input. I was interested in building a kayak or canoe out of styrofoam, then covering it with fiberglass. maybe I should just consider doing one out of door skin and covering it with fiberglass.

Greg

[rgranger]

Greg

All the things these guys said is basically true but I feel you were asking a different question than the one they answered for you.

Look at this site.

http://homepages.paradise.net.nz/garyd/quikama.html

This is a commercial boat builder using styrofoam core.


You can use closed cell styrofoam covered in epoxy based fiberglass with no problems. It is rigid and resists water penetration. If the foam is completely covered then there is not an issue with solvent degradation. The blue foam pictured in the above link is nice but DuPont makes a 3" pink version of the same stuff. Home Depot caries it in 3'x8' sheets. A kayak would make a nice project and two layers of epoxy glass and you would have a light an strong boat.

One more thing. PU foam will handle polyester resins but it does not like epoxy. PU foam core is what surf boards are made out of. If you want to go PU look up some sites for surf board foam.

Some people like polyester and others like epoxy.

C-ya on the water.

rob

[apex1]

Sure you did notice that this thread died already three years ago!?

And for a good reason: Styrofoam has nothing, absolutely nothing to do with boatbuilding! There is not a single application one could use that stuff.
And what you call a "commercial builder" is just a backyard tinkerer.

Regards
Richard

[gonzo]

Styrofoam works well as insulation. We have also used it extensively on hard tops and decks as a core between thin plywood. We used epoxy as an adhesive. The close cell polyurethane is rated for ground contact.

[apex1]

Styrofoam works well as insulation. We have also used it extensively on hard tops and decks as a core between thin plywood. We used epoxy as an adhesive. The close cell polyurethane is rated for ground contact.

Poor choice Gonzo! I regret to say that, there is better stuff around at almost the same price.

[gonzo]

Name one better material at the same price. Also, please explain why it is a poor choice. Have you done any testing? Commercial boats have been working for years with decks and hardtops built like that. It seems like your opinion is not based in facts but preferences.

[apex1]

Almost the same price I said! We are talking insulation and we are talking sqare meters not acres right? Then the close cell Cyclopentan expanded PU is the far superior choice. You are too professional that I must declare why!
And of course it´s my opinion, based on technical properties not preferences. Professionals do´nt have preferences, they strictly use the best material available for the job, or they are not long amongst the professionals.
But as a structural member (and that was the original question) even that PU foam is not the best choice, let alone the white crap.

Regards
Richard

[gonzo]

It pink or blue not white. I am talking about the closed cell foam. In spite of your rather emotional posts, you are not naming any material at about the same cost as the close cell polyurethane that is better.

[Steve W]

There are applications where styrofoam will do the job ok,an example where i have used it was on a 24ft ULDB which i designed and built in 1987,the hull used klegecell and vinylester,the decks were ply/klegcell/glass but as i was installing full foam floatation under the berth tops i made them of 1 inch pink foam with a layer of glass cloth /epoxy on each side,peppered them with 2inch holes and glued them down and poured 2 part bouyancy foam thru the holed and let it foam out the holes like cupcakes and then cut them off and put light glass over,a lot lighter top than plywood or any other foam for that matter and laughably cheaper,has worked great for 20 yrs.I have also used it as a core in a doghouse top glued with resorcinal which i think works better than epoxy for this application(for many other too)but i also included WRC 1x around the perimeter and as beams across so it was 4mm ply as the bottom skin,wrc perimeter and as beams on maybe 16in centers,styrofoam glued between and 4mm ply top skin dynel sheathed,worked well.
Russ Bowler built the 18footer "Benson and Hedges" in my shop 30 something years ago out of polystyrene/epoxy with an aluminum space frame to take the huge rig and daggerboard loads. CSK built a small bridgedeck cat back in the 1960s appropriatly named Foamy which was raced in west coast races down to mexico. Malcolm Tennant regularly speced ply/foam/ply with polystyrene for bridgedecks.I personally wouldnt use it for hulls as it has very low peel and sheer strength, but as with everything it does have its uses.
Steve.

[boat fan]

It would not really make much sense using it for a canoe. or kayak.

Much easier to use single skin plywood and you can always add floatation with water tight compartments or foam.

[gonzo]

They use to make sailboats made out of solid styrofoam. The softboards (surfboards) are styrofoam covered in some kind of fabric. I saw a kayak carved out of a huge block of styrofoam. I think it gives you an cheap and easy way to experiment with shapes. You can glue more foam or carve some off.

[boat fan]

They use to make sailboats made out of solid styrofoam. The softboards (surfboards) are styrofoam covered in some kind of fabric. I saw a kayak carved out of a huge block of styrofoam. I think it gives you an cheap and easy way to experiment with shapes. You can glue more foam or carve some off.

Yes it would shine if you wanted to alter shapes quickly and easily.
Carve away as much as you want.......
Often it`s used for prototype development for those reasons.

Surfboards do use styrofoam cores but not all .Quite acceptable for something that does not spend that much time in the water after all.
Styro cored surboards do break easier than the polyurethane cored ones. Stringers are sometimes placed in the centre.

I would rather still choose a well designed kayak for my needs and build in a more conventional method.

[Herman]

And about polyester resin and styrofoam: There are certain types of polyester resin that will work. They are not common, you will have to search for them, but there are some available.

In Europe, I know of 2 places to get it: Nord Composites in France, and Brands Structural Products in the Netherlands.

[frankseales]

I tried the method you were thinking of but i covered the styrofoam with epoxy and micro-baloons first to try to protect the styrofoam fro the polyester resin. The polyester resin still managed to get through the epoxy and attack the foam but all in all it worked. I think a better idea would have been (and ill try that next time i build a kayak) to make a mould with ply in roughly the shape of the kayak and use the 2 part PU foam. This way you can make the foam whatever density you want and use straight polyester resin. Also i did the volume calculations and it would be cheaper to get the core this way rather than buying a block of styrofoam as i did. Also epoxy resin is much more expensive than polyester resin so cut costs again.
Here is a link to the photos of the build process
http://www.facebook.com/album.php?aid=570838&id=669530715&l=3e4e01d5c0

[Steve W]

Herman is right, duratec is one maker of a polyester for use on styrofoam.
Steve.

[ondarvr]

You can also buy it from Composites One, the demand for products like this is low, so it will need to be ordered.

[pcfithian]

Styrofoam works well as insulation. We have also used it extensively on hard tops and decks as a core between thin plywood. We used epoxy as an adhesive. The close cell polyurethane is rated for ground contact.

Thought it might help to link this thread, http://www.boatdesign.net/forums/fiberglass-composite-boat-building/extruded-polystyrene-xps-24213.html

to this discussion. XPS foam is available in green as well as blue and pink.

[Mr Efficiency]

Discussing the utility of various foams is advanced somewhat by more attention to the densities that are available, low density may be of no use in some applications but perfectly adequate in others, condemning a type of foam without reference to grade ( read density ) is often misleading.

[grigerar]

Hi, I had once a high density styrofoam sailboat (8 foot or so) I bought second han and it was great!

[tunnels]

I'm interested in building a boat out of rigid styrofoam and covering it in fiberglass. I was wondering if anyone can tell me if this would work or will the fiberglass eat away at the styrofoam, any help anyone can give me would be greatly appreciated.

Greg

USE EPOXY RESIN !!!:idea:

[rasorinc]

Stryofoam does not react to epoxy. It is OK to coat it with epoxy. Stryofoam does react to direct sunlight. It needs to be protected from [UV] rays and epoxy does not do that-but paint over epoxy can.

[tunnels]

Stryofoam does not react to epoxy. It is OK to coat it with epoxy. Stryofoam does react to direct sunlight. It needs to be protected from [UV] rays and epoxy does not do that-but paint over epoxy can.

Paint the epoxy with a barrier coat then a top coat !! :D

[PAR]

USE EPOXY RESIN !!!:idea:

Did I read this right?

[tunnels]

Did I read this right?

Ummmm not sure !:confused:

[waikikin]

Ummmm not sure !:confused:

It quite plainly & noisily suggests to use epoxy resin on styrofoam the way I read it, thats what you wrote, I'd use it too:cool:

[tunnels]

It quite plainly & noisily suggests to use epoxy resin on styrofoam the way I read it, thats what you wrote, I'd use it too:cool:

Messy but it is possible to spray candle wax over the surface of the Foam and then use Polyester resin or even Vinylester . Have to have everything warned including the air to the gun is best warmed . Take your time and let the wax harden a little and spray again and again . till it is sealed . Naturaly the resin wont stick to the wax but it is possible to cover it with Glass !!.
Epoxy is much more simple and less hassle so why bother with the hassles !!:o

[Steve W]

Using epoxy over styrofoam seems like a waste of money me as the only reason you would chose styrofoam as a core in the first place is to save money and then you spend a lot more cash for epoxy? it makes no sense. Lets ne clear,THERE ARE POLYESTER RESINS THAT DONT MELT STYROFOAM that can be used as a first coat. Dont waste epoxy with a styrofoam core, use a proper core. I have used styrofoam as a core several times sandwiched between 4mm plywood for a hard dodger top and in a catamaran center pod build, in both cases i used WRC around the perimeter and as transverse beams, the dodger top was glued with resorcinal, the other epoxy(obviously you would not use polyester for this use.
Steve.

[Steve W]

Back in the 60s CSK built a 24ft bridgedeck cat out of strip planked 4 lb density styrofoam glue and glassed with epoxy, the boat was named Foamy, she was 1800lbs at launching in january 1968 and was raced two weeks later to Acapulco with a crew of four, they were ballsy back in those days. I wonder if she is a survivor somewhere.
Steve.

[L'eau.Life]

I'm tinkering with the idea of adding a flybridge to my powercat and even though the cabin top easily takes the weight of 4+ people, using built-in furniture to provide extra strength. To keep weight down (essential on a cat) I'm looking to use epoxy glass over foam so have been searching this and other threads for ideas to keep costs as low as possible . Other than windage and residual spray there should be no real loads so was planning to construct solid sides from 70mm "goldfoam" XPS (http://www.composite-nz.co.nz/dynamicPage.asp?pageID=21) and laminate 10mm sheets of the same to form the curved front combing. For the furniture - essentially boxes glued and laminated onto the roof - the same company has a product called e-board (http://www.composite-nz.co.nz/uploadfiles/E-Board%202.pdf) where I reckon a mix of 13mm for general use and 43mm for built-in ice-chest should work well.
My questions:
a. Does anyone see problems with this as a product?
b. What sheathing (cloth, weave, mat etc.) would be appropriate and how many layers?
Thanks, Alan