Deck core material question??

[JohnC]

I am planning my deck build and I’m a bit confused about some of the core material options. I want light & strong (me and everyone else!) and there are a few ways to get there. My plans it to cut & dry-fit the core material then layup on a flat table. I would like to vacuum infuse but I’m a bit intimidated when I add the cost of core material, glass, epoxy!!! That’s a lot riding on one error free VI pull.

Single level deck for a 20ft SeaCraft is (4) – 4 x 8 sheets (I’m using 1” thick core).


Core options:

Divinycell H-80, 5# density foam; 4’ x 8’ x 1” sheets are $425
Corecell M80, 5# density foam; 4’ x 8’ x 1” sheets are $320
Nida-Core 5# density honeycomb; 4’ x 7’ x 1” sheets are $75
Coosa Bluewater 26# density foam; 4’ x 8’ x 1” sheets are $400

And for comparison!
Marine Grade A/B fir plywood (about 45# density); 4’ x 8’ x 1” sheets are $230


First question – what’s the difference between Divinycell and Corecell. Doeas the added cost for Divinyvell buy you anything?
I have heard that one is better in the South Florida sun than the other but I can’t find anything concrete to support this. I also can’t recall which is one more heat tolerant. Both manufactures state that their 5# core is suitable for decks, fatigue areas, etc. If I decide to VI my deck it will be one of these cores.

Second question – Is there an advantage/disadvantage with honeycomb over the foam cores. Nida-Core is not suitable for VI but if I do a hand layup, it’s an option that would save about $900+. The weight isn’t really any different according to the PDS.

Regardless of what I use I plan to buy 1 sheet of Bluewater 26 to use in the areas under the console & leaning post & around the bilge hatch. Nothing would be screwed to or thru-bolted to a low density foam or honeycomb deck.

Long winded I know!!!

[jorgeinmiami]

I did mine with 1/2 NIDA core, don't remember the density, and the areas where the console leaning post etc was also blue water.

I'm a sorta heavy guy and my 2 boys are extra large, and I see zero flex on the deck. Laid up glass on both sides ..so far so good

For the transom I went with Arjay and it solid as a rock

[FishStretcher]

I have used divinycel and nidacore. Neither will hold screws. Both work great for seats and decks. I used pre-skinned nidacore for seats because it’s easier for shapes like that. I am happy with both after several years of abuse. Remember that topside needs glass to resist a penetrating injury to the deck. The underside can be lighter

[dirtwheelsfl]

Those prices for divinycell and corecell seem backwards. Corecell is better for heat/impact (better everything really). Dark nonskid could become a worry with heat but no one in their right mind would do that…

Any of those cores will be just fine for that purpose. Coosa makes a 15 and 20lb too, but I wouldnt use coosa if i was tryin to save pounds.

Ive done decks in all those materials but for my money itll be handlaid honeycomb. Its got good compressive properties which is what ya want. You wont notice any difference in the boat between honeycomb and the foams to justify the cost. The foams might be a bit quieter but not enough to notice. More work to deal with the open cells when ya cut for a hatch but not much in the grand scheme.

They make the honeycomb with and without a membrane underneath the scrim on top of the open cells. Get the one with the membrane as it blocks resin from draining into the cells.

[kmoose]

Originally Posted by dirtwheelsfl

Those prices for divinycell and corecell seem backwards. Corecell is better for heat/impact (better everything really). Dark nonskid could become a worry with heat but no one in their right mind would do that…

Any of those cores will be just fine for that purpose. Coosa makes a 15 and 20lb too, but I wouldnt use coosa if i was tryin to save pounds.

Ive done decks in all those materials but for my money itll be handlaid honeycomb. Its got good compressive properties which is what ya want. You wont notice any difference in the boat between honeycomb and the foams to justify the cost. The foams might be a bit quieter but not enough to notice. More work to deal with the open cells when ya cut for a hatch but not much in the grand scheme.

They make the honeycomb with and without a membrane underneath the scrim on top of the open cells. Get the one with the membrane as it blocks resin from draining into the cells.

100% Yep!

[JohnC]

Thanks for the feedback.
After some trial and error, every part I've made with infusion has been lighter than I can make with hand layup. I don't know the glass to resin ratio but I definitely use less resin to saturate the glass. I have this fantasy of making a hundred-pound deck and gluing it in. That being said, hand layup seems like a safer bet when I add all of the cost of the parts. I'm not confident that I can do a part that size perfectly the first try.
With no good reason for foam core, I'd rather save the cash and buy Nida-Core. I gave up on my budget a long time ago but every little bit helps. Hopefully I'll be shopping for deck hardware soon. I can blow several hundred on the Gemlux website without breaking a sweat!
The Nida-Core at Merritt Supply has a plastic membrane under the scrim. Thanks dirtwheels for the heads up to look for that.

[jorgeinmiami]

I bought my NIDA core and resins at FGCI I in Ft Lauderdale. Not.a far drive from Miami

[dirtwheelsfl]

The one i put in my 19 weighed 85 before i set it in. But it was 1.5”, and got another layer of 17oz and a layer of some tight woven after it was in the boat. It was a bit shorter too due to the casting decks. 100 will be in the ballpark i think.