# Core Material



## jonrconner (May 20, 2015)

Think about marine ply, 3/8” Okume is very light and if coated with glass and epoxy will last forever.
JC


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## Fishtex (May 10, 2014)

Marine ply, such as Okume is so much lighter than exterior grade and it’s free of voids. Exterior grade is full of voids, soaks up too much epoxy, will “check” if not really saturated with epoxy and glass. Also, I would not use polyester resin as it doesn’t bond well with wood, and you will end up using more glass/mat and end up heavier with a weaker structure. Go to Bateau.com, read some tutorials, go to the forum on boat repair and get some advice. If the boat is worth working on, then it’s worth doing it right.


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## CurtisWright (May 9, 2012)

Call a few fiberglass shops and see if they will lay up a front deck for you. Most have generic molds they can make work. Then you can cut/fit it and glass it in. It will probably only cost ~$100 over what the materials cost buying them at retail prices. Most places should have a basic right angle mold where they can make you something like the decks below. The majority of labor will be cutting to fit, glassing in, painting and non-skid. All the things that you can do easily.


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## Pole Position (Apr 3, 2016)

I would think 1/2" properly framed / glassed would be more than enough to hold whatever weight you put on it. Also, you may want to check out the Airex products; I dont know a damn thing about them other than they are substantially cheaper---usually @ $100.00 for 1/2".

That being said, Curtis probably has the best idea above....


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## Monty (Jan 10, 2018)

Thanks. I'll see if I can find 3/8 Okume. I'll also check with Mirage Boats in GV as Curtis suggested since they may have a mold and can build a deck with fiberglass. Last time I went down there, the shop foreman was nicknamed smurff or something like that. Super nice guy, really wants to help.


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## Pole Position (Apr 3, 2016)

Not sure how far you are from them, but BBC in Vero Beach has okoume and meranti at decent prices.

https://boatbuildercentral.com/?_ga=2.127718404.889763177.1518816320-1827291740.1518816320


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## seapro17sv (Feb 3, 2015)

Pole Position said:


> Not sure how far you are from them, but BBC in Vero Beach has okoume and meranti at decent prices.
> 
> https://boatbuildercentral.com/?_ga=2.127718404.889763177.1518816320-1827291740.1518816320


3/8" Okoume or Meranti from Boat Builder Central in Vero is all you need if you don't mind the drive, and you can afford either. Call Jeff and see if they'll ship 1 sheet, but if not, ask if he's doing any deliveries over your way any time soon, and I'm sure he'd be happy to drop off a sheet. For your purpose, a flat deck I'd use the Meranti at 37 lbs a sheet for $81.00, and only 7 lbs heavier than the Okoume at $96.00. You can use their Marine Epoxy, which is excellent, and they have a 3 quart kit for $51.00, and a 1 1/2 gallon kit for $96.00. You will need some framing underneath the deck for support, but 3/8" with 6oz. woven is what I've used on my 3 Bateau builds. Also buy a pound of wood flower for fillets, and some West System 410 fairing filler if you plan on doing a really nice finish. If you can't afford to go this route, or can't make the drive, pick up a sheet of 1/2" finished ply at Lowes or H. Depot, not the cheap CDX crap. They carry a pretty good sand ply that's very straight, and without all the plugs and voids, that properly sealed with epoxy will be fine, just a bit heavier. Whatever you decide, do not use polyester resin, epoxy only with wood construction. Good luck with whatever you decide.


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## topnative2 (Feb 22, 2009)

Nidacore. 

wood rots


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## seapro17sv (Feb 3, 2015)

topnative2 said:


> Nidacore.
> 
> wood rots


Wood rots? Really? Tell that to Spencer, Rybovich, Buddy Davis, Sonny Briggs. Paul Mann, etc., etc. Most of the multi million dollar custom sport fish boats are Okoume plywood and epoxy. Stronger, lighter, and quieter than an all fiberglass boat, and impervious to water intrusion forever, as opposed to polyester resin.


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## yobata (Jul 14, 2015)

I have also heard of people using baltic birch (although I have never used it myself in marine applications). I went to a local lumber yard and just ordered some for a ping-pong table I am building. It comes in 5' x 5' sheets only (which may be enough for your purposes) and it cost ~$34 for a 1/2" sheet. It is also 9 plies and zero voids!


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## Monty (Jan 10, 2018)

Thanks for the guidance. Its greatly appreciated.


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## topnative2 (Feb 22, 2009)

seapro17sv said:


> Wood rots? Really? Tell that to Spencer, Rybovich, Buddy Davis, Sonny Briggs. Paul Mann, etc., etc. Most of the multi million dollar custom sport fish boats are Okoume plywood and epoxy. Stronger, lighter, and quieter than an all fiberglass boat, and impervious to water intrusion forever, as opposed to polyester resin.


Different needs for different boats.All the above named boats go in for repairs to wood structures.I have seen it.
Great boats built the way they need to build them.
Wood is wood.


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## albrighty_then (Jan 11, 2017)

You can get 1/2 Airex sheets from gulfstream composites for a decent price if you want to go composites


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## predacious (Sep 1, 2016)

seapro17sv said:


> Wood rots? Really? Tell that to Spencer, Rybovich, Buddy Davis, Sonny Briggs. Paul Mann, etc., etc. Most of the multi million dollar custom sport fish boats are Okoume plywood and epoxy. Stronger, lighter, and quieter than an all fiberglass boat, and impervious to water intrusion forever, as opposed to polyester resin.



true,they're made from wood

false they last forever - lots of upkeep on those hulls,don't kid yourself...


wood is trouble ! CDX grade plywood,especially the pressure treated is the cheapest crap you can get...

composites are always a better choice


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## DuckNut (Apr 3, 2009)

IF your heart is set on composites a trip to Lakeland will save you some money.

Composites One or North American Composites carry a brand by the name of Polyumac. Polyumac aircell is an expanded foam and is completely compatible with your project.


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## WhiteDog70810 (May 6, 2008)

I think there needs to be a sticky ply vs composite thread.

Nate


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## seapro17sv (Feb 3, 2015)

predacious said:


> true,they're made from wood
> 
> false they last forever - lots of upkeep on those hulls,don't kid yourself...
> 
> ...


I'm not saying ply is better than composite, just saying they are both just the core of a fully epoxy and fiberglass encapsulated hull, and we're not talking about CDX, or pressure treated crap from a big box store. Okoume ply has to withstand a 30 min boil test, and in fact I submerged a 1" square piece in a jar of water for 4 months with zero change to the plywood, with only the water turning a little tea color. The only way water will ever touch either a plywood or composite core is if you put a hole in your boat, or through improperly installed bolts, screws, through hulls, etc. What I'm trying to say is there's no valid reason to be afraid of using wood in boat construction if done the right way. Also, when you say there's lots of upkeep on the boats I mentioned, please explain what upkeep you're talking about. These are not planked hulls with caulking between the planks, the hulls are completely encapsulated in epoxy and fiberglass, so there's no upkeep as far as the core material is concerned.


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## DuckNut (Apr 3, 2009)

WhiteDog70810 said:


> I think there needs to be a sticky ply vs composite thread. Nate


The truth is out there. One just needs to go find it and read it. There are many really smart scientists who have tested these products and have published volumes of proven data.

Each one has a place and use.

Creating a sticky would only garner opinions without any scientific data to back up such opinions.

As an example: 


seapro17sv said:


> The only way water will ever touch either a plywood or composite core is if you put a hole in your boat,


This statement is not true whatsoever but it has merit on the context. There is moisture in the sandwich whether it is wood or foam and will be trapped once sealed.

Florida Atlantic University performed research for the Navy and concluded neat epoxy absorbed much more water than neat vinylester.

Also: The coefficients of diffusion and moisture saturation values extracted from the curves are significantly greater for the water immersed condition than for the exposed to elevated moisture one, and point to the foam core as the most absorbing material in the sandwich structure.

Composite Structures Absorb Moisture • Moisture has detrimental effect on Composite Sandwich Strength

Both methods are generally accepted and can successfully be used. Not only both methods (wood/foam) but epoxy, polyester and vinylester can be teamed with the two cores to produce suitable products.


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## predacious (Sep 1, 2016)

seapro17sv said:


> I'm not saying ply is better than composite, just saying they are both just the core of a fully epoxy and fiberglass encapsulated hull, and we're not talking about CDX, or pressure treated crap from a big box store. Okoume ply has to withstand a 30 min boil test, and in fact I submerged a 1" square piece in a jar of water for 4 months with zero change to the plywood, with only the water turning a little tea color. The only way water will ever touch either a plywood or composite core is if you put a hole in your boat, or through improperly installed bolts, screws, through hulls, etc. What I'm trying to say is there's no valid reason to be afraid of using wood in boat construction if done the right way. Also, when you say there's lots of upkeep on the boats I mentioned, please explain what upkeep you're talking about. These are not planked hulls with caulking between the planks, the hulls are completely encapsulated in epoxy and fiberglass, so there's no upkeep as far as the core material is concerned.



you need to travel to a few yard in the OBX and the Deltaville VA region...


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## predacious (Sep 1, 2016)

DuckNut said:


> The truth is out there. One just needs to go find it and read it. There are many really smart scientists who have tested these products and have published volumes of proven data.
> 
> Each one has a place and use.
> 
> ...



"Composite Structures Absorb Moisture • Moisture has detrimental effect on Composite Sandwich Strength" - coosa board/Penske board will absorb less than 1.5%...http://coosacomposites.com/site-content/3-bluewater-panels



"Florida Atlantic University performed research for the Navy and concluded neat epoxy absorbed much more water than neat vinylester" - I think perhaps that's backwards ? epoxy is waterproof,vinylester isn 't....


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## seapro17sv (Feb 3, 2015)

DuckNut said:


> The truth is out there. One just needs to go find it and read it. There are many really smart scientists who have tested these products and have published volumes of proven data.
> 
> Each one has a place and use.
> 
> ...


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## DuckNut (Apr 3, 2009)

That was the point of my post. In addition if you read my other posts on the topic, I too am usually for quality marine ply (never outdoor or treated).


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## DuckNut (Apr 3, 2009)

predacious said:


> "Florida Atlantic University performed research for the Navy and concluded neat epoxy absorbed much more water than neat vinylester" - I think perhaps that's backwards ? epoxy is waterproof,vinylester isn 't....


 The equilibrium weight gain ranged from 1.8 to 3.8% for the resins. The long‐chain, low‐crosslink‐density epoxy system (SC11) absorbed the highest amount of water and was saturated first, and it was followed by the medium‐crosslink‐density (SC15) and high‐crosslink‐density materials (SC79). 

https://onlinelibrary.wiley.com/doi/pdf/10.1002/app.28076


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