Deck Recoring Material

[Perithead]

I am working on recoring the foredeck on my little South Coast 22 project boat. I have the deck ripped off and the old rotten balsa core removed and I am ready to epoxy in the new core material, but I have thoughts about what material to use.

The deck isn't flat but has an arc to it so a sheet of plywood is probably out of the question. Originally the core was balsa so I could put that down, but I have read, it seems, about other alternatives to balsa and I was wondering if someone could shed some light on that for me?

Also, if I did go with balsa or some other material, where would I go about finding this stuff? I am not in a coastal town so there aren't any good marine stores around. Could the correct balsa be bought locally?
I know hobby shops have balsa for building models but I am not sure if that would be my best option.

So-
Balsa or is there a better alternative?
Where can I find the material?
What size balsa might I need? (3"x3", 4"x4", or something else?)

Thank you all and may winter pass us by quickly!

[Mechsmith]

There is a product that I think is called "Hollofill". Basically it is a mat of hollow fibers that are installed much like fiberglass. I saw it used at a boat building school in Wilmington NC as both stiffener and flotation for a small boat. I have seen it advertised other places. Try the MAS epoxies website for some ideas .

[sailingdog]

Perithead—

Marine Plywood is a horrible choice for core materials, as I've written about in this post.

I would recommend going with Airex, which is a ductile PVC foam. It is probably flexible enough to follow the curvature of the deck without having to resort to slicing kerfs into the material.

If you wanted to go with end-grain balsa, you'd probably want to get something like Baltek ContourKore.

I seriously doubt that anywhere local is going to have either material in stock. You will probably need to mail order it or have someone special order the material.

I would recommend using Progressive Epoxy Polymers products unless you have to work in colder temperatures. For that there is a special purpose cold-temperature curing epoxy made.

[Perithead]

Can't seem to find Hollofill for some reason on Google.


SD- Thank you for the suggestion, it looks like the Airex is more than twice the price of the end grain balsa and I don't see a real need for anything more than that on my little South Coast 22 sailboat.

It looks like both products don't soak up much resin so that is a good thing. It looks pretty straight forward though, puchase enough square footage, prep my surface, wet out the surface, lay my core, then fill the kerfs?

Since there is an arc like a rainbow I am thinking my kerfs need to be up to let the material bend. I read about the installation of the product and I interpretted that you don't neccisarly have to fill the kerfs so I could just wet out the outer surface and apply my layers of fiberglass to form my deck surface?

All done with the repair with only painting left?

[sailingdog]

You really should fill the kerfs with thickened epoxy if you can. It will make the repair a good deal stronger.

As for wetting out the surface... you should wet the prepped deck inner laminate with unthickened epoxy and then put on a thin layer of thickened epoxy to help the balsa bed properly. The balsa should also be pre-wetted with unthickened epoxy to prevent it from stealing epoxy from the thickened epoxy bedding layer and causing it to not bond properly from insufficient epoxy.

Then the upper surface of the core material (assuming you're using the balsa) should be wet out with unthickened epoxy and then coated with a thin layer of thickened epoxy and then the top layers of glass laid down over that. I hope you left enough of the top laminate at the edge for you to have something to tab the repair to.

The major advantage of airex is that it does not rot.

[mitiempo]

Second what sailingdog said above. I would use contourkore balsa which is light and strong. Balsa is a good core material as long as it doesn't get wet from bad hardware attachments. If water gets in any core is at risk.

[AHD]

I believe there's a product line with the generic name "c plex" Haven't applied it for some time but it consisted of a "mat" of fiberglass with "strands" of interwoven epoxy (material) type cording every c. 3 ". It came in 4' to ' sheets that could be cut and applied (by screws & epoxy to the 1st sheets, initially) and then gel coated over and process repeated. If available it should extend the "useful life" of your deck radically. Hope this helps.

[Perithead]

Thank you all for your advice, I'm going to get some of the balsa material and see how it works out. I will post how it ended up.

Thanks again...

[mitiempo]

Here's a link that might help. Tim Lackey does a lot of deck recores and they are all documented on his site. Click on recent work or current work and it will show step by step recoring and any other work a boat has needed.
Northern Yacht Restoration | Tim Lackey:* One Man, One Boat at a Time

[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