Joint method for Coosa

[msteimer]

Guys,

Just received 2 sheets (5'x12') of Coosa for the cockpit sole. Does anyone have recommendations on a joining method? Will a butt joint do or do I need to do something like a scarf joint?

Plan on glassing after joining, so not sure how much strength the joint needs. Advice appreciated.

Mark

[CamB25]

On my deck we used a rabbit joint made with a router. Pre-glass the top and bottom surfaces off the boat, leaving a 6" or so wide open area on the top surface covering the joint. Bond the panels together on the boat and glass over the joint. This kept the finished deck "reasonably" flat and reduced the amount of grinding required before fairing. I forget if we used two layers of 1808 on the bottom and one on the top, or visa-versa. Regardless, the coosa deck is absolutely solid and stiff.
We used polyester resin and added some gel coat to the top layer to pre-fill the weave. Not a great shot, but you can see the joint area.



Good Luck!
Cam

[Marlin]

What's your final deck finish going to be?

[msteimer]

Open to suggestions, but was thinking paint with nonskid.

[JimmyG]

I also did this and used a rabbit joint, worked great then I ruffed the surface and glassed over it with a sheet of biaxel with polyester laminating resin and the problems started, i faired then epoxy primed and painted it and once out side in the sun big blisters appeared so i ground them out and did it over, a few weeks later more blisters! I gave up for now... some kind of gassing problem I think

[Marlin]

Maybe way out thinking from your plan, I fabricated deck supports from 3/4" coosa, kinda like an I beam that was held up from the stringer with coosa vertical studs. If I were going after the finish product u described, I would then epoxy the decking onto the top of the 4" I beam I described, strb, middle and port sections, fasten with some waxed drywall screws ,remove them the next day,add a layer of 1708 on top of that, fair out the entire surface with thickened epoxy/cabosil,paint out with the non skid process. This system isn't easily removable but that should not enter the decision making process, when the boats were built, no one anticipated they would be going thru major surgery 50 years later!

[John Vyn]

For your sub structure I would fiberglass "c" channel from McMaster Carr. I removed all wood and build 4 longitudinal stringers and bonded them to the stern of the boat. Forward I used a channel and cut to dove tail to the main channels bonded to each main channel so I had a bonded box. Vertices were "c" Channel bolted to the framework on top and to the boat reinforcements below. Makes a strong solid structure for the deck.