Deck Recoring Material

[sailingdog]

Normally, I'd recommend Divinylcell for a foam core for use in a deck, but divinylcell is too stiff to bend and conform to the curvature of the deck in this case more likely than not... so recommended airex, which I normally would recommend for hulls, rather than decks.

Originally Posted by boatpoker

While balsa is fine if installed properly it can deteriorate quite rapidly if the skin is punctured by fasteners. Neither am I a fan of Airex as I have seen it deform in very hot weather. My money is on Core-cell.
Core-Cell

[pearson30sailor]

when the deck is slightly sunk under the mast where mine is, what is the best material to us when I step and do this repair? I was considering glassing in a large aluminum plate. would be a wise way to repair this? i will be repairing my compression post as well.

[mitiempo]

It has to be uncompressable and bond well and aluminum would work. But I'd use solid glass, multiple layers of 1708 biax and epoxy which will build up thickness fairly quickly. Don't lay up too many layers at a time though or it will get too hot. There's a lot of force on this part of the deck and if you use epoxy and glass there's no reason for it to ever be an issue again. By using different materials you introduce a possible future problem.

[sailingdog]

Second what Mitiempo said... a solid glass plate would be better than aluminum, especially if you have fasteners going through the mast step and cabin top. Aluminum can have corrosion issues with stainless steel fasteners, which are not an issue with a fiberglass plate.

[eherlihy]

IF you are interested,

My friend's company has been providing the core material for the Composite Deck House of the US Navy's new DDG Destroyer. I know that they went through an exhaustive certification and qualification process. This material "is a completely isotropic material that provides excellent strength and stiffness, finding use in critical areas where the performance of lesser core materials such as Balsa, Honeycomb or blown foams may not be sufficient." I know that it is a resin/macrosphere matrix, and that its characteristics are not affected by the presence or absence of water. If I have to do a re-core, I plan on using it (good enough for the USN is good enough for me!)

The material is available in different densities, each with different compressive strength and shear characteristics:
Density (lb/ft3)
19 (± 1) 23 (± 1) 28 (± 1) 33 (± 1)

Compressive Strength ASTM D 1621
1,400 psi 2,100 psi 3,200 psi 4,700 psi

Compressive Modulus ASTM D 1621
53.1 ksi 81.3 ksi 86.1 ksi 90.3 ksi

Shear
600 psi 900 psi 1300 psi 1600 psi

If you would be interested in trying this material, PM me.

[Keldee]

Dont forget, after you have repaired the coring, to correctly bond the hardware fittings to prevent leaks from seeping into the new coring and also able to withstand compression loads exerted by the fittings through- bolts and nuts. This process is explained in the West System booklet "Fiberglass Boat Repair & Maintenance"