Foam core, Roof

Roof Rim Foam Glued On

Posted by Paul

The intention of the foam to create a lip around the cockpit roof is threefold, so that rain will not drip randomly over the edge it should pool and be drained where it want it to or at least predictably, also so that I have a flat surface for attaching a hold rail that I intend to run around the entire roof all the way up from the deck and around to the other deck and to run a uni rope around angled from the front face over to the top face so that when set this uni acts like a girder to stiffen up the roof left to right, and hopefully a similar structure around a solar panel box and perhaps the uni around the sunroof cut-outs will stiffen the roof fore and aft.

I had already glued the front foam around the edge, today with the roof leaning up on the drums I was able to get under the roof to glue the edge strips on. To create the strips I ran the portable saw with a fence on along the edge of a foam sheet to create 40mm (the foam sheet thickness) by 20mm (the depth set to the fence) strips. They are fairly flexible buy not flexible enough to bend around the 2 curves across their fat side without some help. (The front strip could be bent around easily). The tight radius back corner bends I did with triangular kerfs cut into the inside of the bend about 35mm of the 40mm depth about 3mm wide at the inside edge down to a point. About 5 cuts like this spaced about 10mm apart was enough to create the bend.

Once I had these kerfs cut into small strips of the foam I dry fitted them, then dry fitted the long strip across the back edge, then finally I set about making the last strips one either side go from the back corner, along the side around the larger radius bend to the roof side. I had intended torturing this around and having Warren screw it in place for me while I held it bent around the corner which I could do. But he suggested a much easier way. Whilst I held the piece in place and slowly bent it around the corner it had to fit on he hit it with a heat gun. As the heat builds the foam becomes more pliable and once fully formed to the curve and cooled again it holds that shape for gluing. Much less work when actually gluing it.

With all the parts dry fit, starting at one end I removed them, buttered them with glue and re-attached them. I squeezed glue into any remaining gaps, cleaned up squeeze out and that was it for the day, or should I say half day. I dont think I will apply the uni before I get the roof on the boat. I am still in 2 minds. On the one hand the more I do on the ground the easier it will be once the roof is up, and the stiffer the roof the easier to handle and finally in the case for doing more on the ground, the foam is quite fragile and dents easily so as soon as the glass is on the structure is more secure. In the case for leaving it until the roof is on, is weight, the more I add now the heavier it is to lift, and if I do need any more minor bends in the roof it will be that much harder once the stiffening uni is on. I doubt I could influence a change in shape now but perhaps if I wanted to pull the middle down or the edges down a few millimetres and I could brace it in some way to set then perhaps doing this on the boat and then applying the uni might help a little.

I will decide which way I want to go in the next few days. I need to put together a roof lifting posse which might take a few days, and I have to set up my braces on the boat to hold the roof in place once it is lifted on, so there is still come work to do first. I am also running out of free weekends before Christmas. Next weekend is Jo’s family Christmas then the following weekend is mine so there wont be much more work done this side of Christmas. I would really like to get the roof on the boat this year though. That would be a nice way to round out the year.

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