recoring a TRIPLE layer flybridge floor

I cut off the top layer of glass on my 1978 Silverton 34C flybridge floor, and found that it has three layers of glass - the top layer, or floor, 3/4" balsa coring, second layer of glass, then what appears to be an air space of less than 1/2", and finally the ceiling of the cabin below.

My probem is that the middle layer of glass, the one that I need to bond new balsa to, is warped. The deck is about 8' wide and I've opened up about 50 sq. ft. of it, as the balsa was rotten and or soaking wet.

I cut open a hole in the second layer, and in one spot I found there is some gray hard putty that appears to have been put in as a spacer.

I want to repair this mess, but if I just bond the new balsa to the middle layer, I'll end up with a warped, wavy floor on my flybridge.

Any one seen anything like this, construction wise? Is there suppose to be an air space between the middle and bottom layers of glass?

I suppose this was done because the ceiling in the cabin is a gloss gelcoat, and the floor of the flybridge is gelcoat also - both surfaces were next to the mold.

Any suggestions on the best way to repair this to keep the flybridge floor at it's original contour?

 

has anyone seen a triple layer flybridge floor? the boat was probably made with a cored flybridge floor, then inside the cabin a "drop" ceiling was installed. anyone done any repairs like this?

 

I had to rebuild the rotten core on my F-36 Trojan. After hacking out all the rotten and mildewed balsa, I realized it was more hassle to patch or save parts of it than a total rebuild. So, I made 5 little jigs with a 3" camber the width of the flybridge and made a new deck out of closed cell foam. It was pretty easy and save a lot of time. I just cut the old deck out all the way to the frames around the edge, dropped the new one in there and glassed it in.

 

Did you make a form and build a sandwich deck - glass/foam/glass? that might be easier for me -hmmm... I have several irregular patches - across the front of the flybridge - about 8 ft. wide by about 2 ft. and a couple more near the back. My flybridge floor isn't flat - it has a slight curve port to starboard. I suppose I could build a form and drop that in. Do you have the extra glass ceiling below the floor?

 

Yes. I nailed 4'x8' foam sheets to the jigs I made. (just cut 2"x4"s to curve a 3" camber for the bridge deck width) Then I glassed over the top and yanked the nails when the glass hardened. Let the nails stick up a couple inches! Then wet it and add another layer of foam sheets and glass over them the same way. Then turn the whole shebang over and glass underneath.

It was pretty easy. 3 of us lifted it up there and set it into place. Where it touchs the wood framing all the way around I generously applied 5200 (around edge) to that wood wouldn't ever get wet. Then I poured West System around the edge and eventually rolled gelcoat on the deck. Instead of painting nonskid on top, I applied a layer of the nonskid that comes in a big roll from Nautilex. But I wish I hadn't...it seems to mildew and get dirty much more quickly than fiberglass surfaces.

I wish I had pictures...but it went so much quicker than expected I never thought of it.

 

hmmm.... about 3/4 of my flybridge coring is in great shape - I just have two areas, one in the front and one in the back that are about 1-2 feet wide, and go the width (about 8 ft.). I want to just repair these areas and leave the rest as is. I think that I'll have to straighten out the bottom layer of glass somehow, as if I remove it and build the whole thing over like you did, I can't figure out how to bond the bottom layer of glass at the edges of the patch.