Deck Delamination / Core Problems

[mbd]

I called Noah's Marine last week and asked about Corecell and what they recommended. I just ordered 6 sheets of CoreCell A500 (B) 9MM PL 23"x48" for $73.14, so that must be close to the same stuff Jeremy used.

[Sprite]

You can buy

by the gallons exact gelcoat and anti skids from spectre or spector products.
They are located in Florida and Washington state. They have anti skid patterns
for Pearson Boston Whaler with the correct color for gelcoat. They have a catalog. If you are looking for an anti skid pattern another place was treadmaster and they are based out of England they were in Good Old Boat
Their stuff is cool.


John

[mbd]

- from Noah's Boat Building Forum Admin in reply to someone's query about materials for a recore:
Foam core (Corecell) will not be affected by water, and installation is about the same (as balsa). One disadvantage is, unlike balsa, foam does not have good compressive strength so it will be necessary to insert plywood under winches etc.

Oy. I guess it goes without saying then that I should pre-plan where all my deck hardware will be re-installed and put something more solid in those locations? Lay-up with fiberglass or use solid epoxy or what?

[ebb]

We obviously have the experts here.

But here's my thought, since I've been messing with the deck on 338.
I'd have to know where all the fittings are going,
and as I don't really really know exactly,
I would proceed with the core and deck lamination and then when it got to placing the fittings, do the oversized holes*, fill with epoxy mush and redrill for exactly where the fitting goes - with a substantial backup plate. It's would be a pain to cut all those pieces of matt and buildup squares of solid glass everywhere in the recore. Yes?
I really like maranti marine plywood, think it's good to bed in epoxy as a backer, and seal with epoxy too.

Some places, like under the mast, I would argue that solid core is best, no foam.

* the divinyl-cell foam I use is closedcell and very non-compressable - so one may not have to clean out holes with a bent nail and fill with epoxy and redrill for a fitting. This is after all the balsa core fix.
But I'd argue that it makes a completely rigid installation of a fitting that way. Because the bolts cannot in any way compress anything. For Instance the lever bending force that can happen with a stanchion base.

[commanderpete]

Interesting. I wonder what the specs are for different core materials.

Might be more of a concern on a larger boat with higher loads.

I agree with ebb. Epoxy plugs would give you pillars of strength.

[mbd]

I suppose I'll have at least a general idea of the location of cleats, stanchions and other hardware and can "block out" a nice sized square for solid material between the skins. But what would that be? Expoxy plus micro balloons, coloidial silica (sp?), cloth fibers, wetted out fiberglass ???

...
OK, I seemed to remember Mike G's response to "mix-ins" for epoxy and found it in Post #131 of this thread: Thanks Mike. (Still waiting on that DVD to come out.)

[ebb]

When you get over to the sheer there is some shaping of the core to do. Why not go with one o Mike's Mixes and trowel in your solids? And fair at the same time. Cabosil with 1/4" or 1/2" chopped strand would be plenty strong. even stronger if you also used flox. Wouldn't have to make squares, eg for the stanshion bases they could be half rounds. Long strips of matt for the track bolts.... etc.
Personally I'm believes in mat and cloth for unadulterated strength and you still could level things up with any mix (not micro balloons in the composite) so your top layer goes on smooth.