ngquail Posted September 22, 2014 Report Share Posted September 22, 2014 I recently started a curlew from the book. So far I have ripped and dressed w.r. cedar for the stringers and have cut out the frames from marine mahogany 12 mm and exterior 9 ply 12 mm baltic birch. I am located in B.C. Canada and found the exterior baltic birch in 4x8 sheets at Windsor Plywood (in case anyone else is looking for it). I boiled a piece of the interior grade baltic birch (sold in 5x5 sheets) but it delaminated with 1/2 hour of boiling. A piece of the exterior grade was still intact after about 45 min. of boiling along with being charred when my pot ran out of water. I figure that should be good enough for a kayak. I will post the odd photo as I build things - this forum has some great ideas that I'm likely to incorporate into the kayak - thanks to all who contributed and to Jeff for his work on the designs and book. Certainly looking forward to getting it onto the water in the spring. John. Quote Link to comment Share on other sites More sharing options...
Kudzu Posted September 22, 2014 Report Share Posted September 22, 2014 Welcome to the forum. Let me dispel the idea that boiling plywood has any bearing on the quality or suitable for kayak building. It is commonly thrown out in forums but how many times do you paddle over an underwater volcano? If I remember correctly this comes from a mil-spec. Epoxy, which is used in most wooden boats, can't pass a boiling test. Buying exterior grade is probably a good idea though. Quote Link to comment Share on other sites More sharing options...
labrat Posted September 23, 2014 Report Share Posted September 23, 2014 Hi there John, 1 thing that is worth doing is the modification to remove the section of frame that is under your calves. I suspect it is part of the plans now (could be wrong on that) but is not in the offsets provided in the first book. You might need to search through some Curlew build logs to see how others did it. There should be photos of mine and there must be others because I got the idea from someone else's build. I can take some measurements for you if it will help, just let me know. Good luck with the build, looking forward to some photos. Quote Link to comment Share on other sites More sharing options...
ngquail Posted September 23, 2014 Author Report Share Posted September 23, 2014 Jeff and Labrat: Boiling the plywood was an easy experiment - and I did want to see if there was an appreciable difference in the glue used in the exterior vs. interior grades. It appears there is. I have noticed the changes in the frame sections ahead of the seating area in a few photos on the forum. I figured I'd look at this further once I have the frame built and can sit in it. Thanks for the offer of measurements I may take you up on it. I was thinking of reducing the height of the lower part of the frame in that area and increasing the thickness but with the cutout for the floor pieces was not sure if that would work. John. Quote Link to comment Share on other sites More sharing options...
Kudzu Posted September 23, 2014 Report Share Posted September 23, 2014 Boiling the plywood was an easy experiment - and I did want to see if there was an appreciable difference in the glue used in the exterior vs. interior grades. It appears there is. I am going to stress this point again. heat was the difference and kayaks never get boiled. So yes there is a difference in the two plywoods, it doesn't have any application to a the real world use in a kayak. The plywood I use fails the boiling test very quickly but since I never paddle in boiling water it is mute point. Soaking a piece in water for a month, that is an applicable test to see how well it holds up. The plywood I use will stand up to that and I have left scraps outside the shop in the weather for months and all that happens is it changes color. I have used it in a lot of boat kits and never one problem. That is why I am stressing this. A perfectly acceptable plywood may not hold up boiling and boiling is not a condition it needs to stand up too. I was thinking of reducing the height of the lower part of the frame in that area and increasing the thickness but with the cutout for the floor pieces was not sure if that would work. That is asking for trouble. The boats you see without the center have different frame design that allows for the missing section. I only offer that on the my full size plans. Doing what your thinking about will weaken the frame and it could break, worse case trapping you in the boat. So don't do it. It took me a long time to figure out how to do that safely and not compromise the frame strength. That is something that is exclusive to my boat designs. Quote Link to comment Share on other sites More sharing options...
woodman Posted September 24, 2014 Report Share Posted September 24, 2014 I had the kayak built according to the plans..... Then I read that Jeff was cutting out the bottom section of the front frame that interferes with your calves, which made sense.... So I added a frame 7'' in front of the seat, I have done this to all my kayaks http://messing-about.com/forums/topic/9217-the-curlew/?p=82616 Quote Link to comment Share on other sites More sharing options...
jlt Posted October 31, 2014 Report Share Posted October 31, 2014 could one add apiece of foam to the seat behind the frame causing calf irritation? Quote Link to comment Share on other sites More sharing options...
Kudzu Posted November 1, 2014 Report Share Posted November 1, 2014 Unless you sit flat legged, legs straight out, the frames will not hit your legs. 1 Quote Link to comment Share on other sites More sharing options...
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