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Foam Core FS14

Posted: Thu Feb 05, 2015 9:14 am
by bainley
Is it possible to build a FS14 using the scored type of construction foam using the same process as you would with marine ply? Only reason I ask is because it would be way easier and less time consuming than cutting the foam into strips and doing it that way.

Re: Foam Core FS14

Posted: Thu Feb 05, 2015 9:21 am
by topwater
Why would you cut it into strips ? If you can form the hull panels with plywood panels foam would form
the same panels no problem. You will need more molds for the foam to support it . Why foam ?
Don't think you will save much weight in a boat this size and it will cost more to build .

Re: Foam Core FS14

Posted: Thu Feb 05, 2015 9:32 am
by tech_support
bainley wrote:Is it possible to build a FS14 using the scored type of construction foam using the same process as you would with marine ply? Only reason I ask is because it would be way easier and less time consuming than cutting the foam into strips and doing it that way.
what foam? Do you have a link or description?

Unless it is a structural foam for composite sandwich composites, then it will not work.

Re: Foam Core FS14

Posted: Thu Feb 05, 2015 10:06 am
by jacquesmm
The comments above are correct:
- no significant gain in weight
- no need to cut strip or use scored foam
- use only true marine foam like the Divinycell sold at BoatBuilderCentral.com:
http://boatbuildercentral.com/products.php?cat=10

I must add the following:
It is possible to build the FS14 in foam sandwich. I am currently building a GF16 using that method in order to produce a tutorial.
The ideal method is to fabricate flat panels of foam sandwich that replicate the bending properties of the plywood.
This means fiberglass the panels with a minimum of glass before assembly.
The tricky part is to specify exactly how much glass to use before bending. Too much and the panel will not bend, too little and it will be flimsy and produce an unfair hull.
After assembly, the hull is fiberglassed with the final layers of glass, more than in the plywood-epoxy version.
I have tested panels and know the bending radii and compounding. For each boat, I can specify how much glass to use.
All our boats can be built that way but I did not calculate the specifications for each of them.
The first small boat plan for which I give foam sandwich specifications (as an alternative to plywood core) is the WE12:
http://www.bateau.com/proddetail.php?prod=WE12
I can give foam sandwich specifications for the FS14 right away.
Keep the following in mind: foam sandwich requires more fiberglass than plywood-epoxy. The materials cost will be double.

Re: Foam Core FS14

Posted: Thu Feb 05, 2015 8:58 pm
by bainley
Ok thanks, I'll keep my eye out for the tutorial. I wasn't looking to save weight, just wanted to try it with a smaller boat before going bigger. Thanks again fellas.

-Brian

Re: Foam Core FS14

Posted: Fri Feb 06, 2015 8:29 am
by jacquesmm
I need about 2 or 3 months before I post that tutorial but there is almost no difference with our current method.
It is an excellent idea to build a small foam sandwich boat to evaluate and learn the technique.

Re: Foam Core FS14

Posted: Fri Feb 06, 2015 2:49 pm
by Marshall Moser
I am also interested in building my FS14 plans in foam sandwich. Once you calculate the lamination schedule/specifications, I'd like a copy to supplement my FS14 plans.

Re: Foam Core FS14

Posted: Fri Feb 06, 2015 3:14 pm
by jacquesmm
I was going to sell that version as a separate plan but if you are serious about building in foam, I will do the calculations next week with some tips. Not a real detailed tutorial but enough to build the boat.

Re: Foam Core FS14

Posted: Mon Feb 09, 2015 11:35 am
by Marshall Moser
The main difference is the lamination schedule for the outer glass, correct?

Yes, I am serious about building in foam and would certainly purchase another set of plans if necessary. Life changes have made building the boat a very near reality. I would like to start once the weather warms up enough to work without heating my garage.

The eventual goal is to build a CS25 in foam core, but I want to start with something manageable to learn on.

Do the pre-laminated panels need to be vacuumed?

Re: Foam Core FS14

Posted: Tue Apr 14, 2015 10:24 am
by jacquesmm
Did anything happen to that project?

Re: Foam Core FS14

Posted: Wed Apr 15, 2015 9:57 am
by Marshall Moser
Were you talking to me?

Well, mainly you designed the FS19. It will be a much more usable boat to me. The reason for me buying the FS14 plans was because the FS17 wasn't really ever big enough for me and I was worried about building the CS25 as a first boat. Plus I would teach my son and daughter to operate a boat using the smaller craft. Now, I feel like the FS19 would be a better candidate. It is a good size for me.

But yes, I would like to learn to use foam core because I feel like the difference in a foam core composite versus plywood core composite completely changes the attitudes surrounding the method and is the difference in a home-built boat and a custom boat. I am undecided on whether or not I would rather build the FS19 in foam or plywood core. I realize this may be confusing, but the hull cost is significantly more in foam, so I'm weighing my options.

I realize that practically, there is not much actual difference in the two composites, but there could be a perceived difference.

Re: Foam Core FS14

Posted: Thu Apr 16, 2015 10:48 am
by jacquesmm
If you decide to build the FS19 in foam core, I will give you the specifications.
First, I must finish the standard FS19 plans.

Re: Foam Core FS14

Posted: Fri Apr 17, 2015 9:18 am
by Marshall Moser
I gave it serious thought last night. If I'm going to build it, I'm going to do it the way I want to. I have decided on foam core. I will also be purchasing the materials from you. I think the pre-laminated panels will be the way to go though. I don't have the nerves for infusion.

Re: Foam Core FS14

Posted: Fri Apr 17, 2015 10:55 am
by jacquesmm
I will post some tutorials about foam sandwich applied to this type of boat. You'll see that you don't need infusion.

Re: Foam Core FS14

Posted: Tue Aug 25, 2015 12:38 pm
by MarkOrge
When I did mine there was no mention of pre-finished panels? I followed the instructions given, using a ribbald mold for the hull. Screwed the foam to the strips using drywall screws with pancake washers, filleted and applied tape to the seams, removed the screws and filled the holes, laid up my full lengths/widths of cloth per the schedule and had my basic hull. Has something changed?

Re: Foam Core FS14

Posted: Tue Aug 25, 2015 1:48 pm
by jacquesmm
The new method is different. We fiberglass one or two sides of the foam panels flat on the floor, in one piece. Then, we use those panels exactly as we would use plywood panels, stitched at the chine.
Fiberglass the chine, bow, transom in and out and depending on the boat, add a layer of glass where needed.

There are several advantages:
- we can control the stiffness of the panels with the first layer of glass.
- compared to other foam sandwich methods, we need less molds

We completed a GF16 that way and the boat is light and stiff.

I am very busy with some other projects but I will post a tutorial one day . . .

Re: Foam Core FS14

Posted: Fri Nov 18, 2022 9:13 am
by shickapooka800
jacquesmm wrote: Thu Apr 16, 2015 10:48 am If you decide to build the FS19 in foam core, I will give you the specifications.
First, I must finish the standard FS19 plans.
Hello, I have purchased the FS19 plans and am interested in fully budgeting out the foam core version. I tried to send a private message however the message is still in the outbox and the webpage shows some php error messages up top. I can provide my purchase information if necessary.

Thanks