About Coring Materials

Types:

Plywood

Generally prefer fir plywood, or modern marine plywoods (ex. Meranti). Do not use pine or pressure treated, the resin content or water content will interfere with resin adhesion or curing.

Coosa Board (Urethane Coring Boards)

Excellent, no rot replacement for plywood. Very flat, very good for screws, very good for resin bonding.

Availible in a number of thicknesses and densities, from a few different vendors even.

Divinycel H (PVC Structural Core)

Curved surfaces

Plastic Honeycomb (Nidacore)

Flat parts or minor shape, quite light weight, no rot, slightly more difficult to work with. Has the appearance of plastic honeycombs, or bundles of soda straws. Traps and holds air so quite low density and good for things that need to float, roofs, decks, etc.

PET

Made from PET plastic (the same plastic as is used for soda bottles), PET foam is a very economical choice for structural coring while being almost as good as polyureathane for insulation ability. Excellent economical choice for stringers (if you don't want to use coosa), decks, etc.

Poly-Urethane

Really mostly useful for insulation foam, ie. coolers fish boxes that sort of thing. Old school choice for stringers, but difficult to work with and fragile.

By: Capt. Ken