Thursday, June 16, 2011

It's a Start

After a week of reading/researching and dredging up materials, I'm actually getting around to starting the Disko Bay. I easily managed to find some cedar at Home Depot that I can rip for the gunwales, chine and keel. Finding the plywood for the frames was another matter. Marine plywood cannot be gotten easily in this neck of the woods. I could order a sheet but the cost would be over 200.00 a sheet - eventhough I only need 1/4 of a sheet. Regular exterior grade plywood can be used but this wood tends to be very splintery when you cut it and often full of voids. I just find it nasty stuff to work with!!  I toyed with the idea of making the frames from solid cedar pieces lap joined together - but that was proving to be too complex a job and I'd be better off going with the exterior grade plywood for the amount of extra work involved.

One more trip to Home Depot yielded an interesting find - Russian Birch plywood. I had no idea if it was exterior/interior or what and the sales dude was not much help either. Interior/exterior plywood is classed by the waterproofness of the glue. Incidently, the standards for testing the glue involves boiling. There was no indication what type of glue was used. My frames call for 1/2". There was 11.5mm and 17.5mm (13 ply) available in 2x4 sheets. Always erring on the side of caution, I grabbed the 17.5mm 2x4 sheet and decided to give it a whir. Without going ahead willynilly and building a boat with plywood that could possibly melt once water hit it, I decided to give this stuff a test. And the test was as follows:

I cut off one corner (there goes any chance for a 33.00 refund from Home Depot), sanded one edge smooth (this stuff has incredibly hard edge grain)  and popped it into a pot of boiling water where it sat for a full hour at a rolling boil. At one point, about five minutes in, I thought the plys were delaminating but on closer inspection, it was refraction or the water distorting how it looked, After an hour I took the piece out and the plies were intact. I took a knife and tried to separate the plies but no go. They were stuck as fast as when they went in. Even the sanded surafce was still as smooth - with no rasied grain!  In a similar test, I dropped in a piece of "supposed" exterior fir plyood but it did not fare so well - I could split the laminations with the knife.

After the boiling I put the test piece in the freezer for a few hours. The dishwasher was due for a run, so, just for poops and giggles,  I took the wood and popped it in with the cutlery. After three water cycles with the water temp at 160, the wood was still intact.  I threw it in the freezer overnight just to be mean!!  The next day, I dropped it diectly from the freezer back into a pot of boiling water. After 20 minutes, I took the boilding water and wood and threw it in a thermos and took it off to work with me. At lunch time, I replaced the water with freshly boiled. After 8 hours in boiling/very hot water, there was still no delamination, nor could I separate the plies with a knife.  That's good enough for me!!   The only consequences of the exposure to boiling water were the facts that the wood swelled about 1mm in width and it went a dull gray-ish colour. Again, fine by me!!   As a footnote - I will be encapsulating the frames in epoxy for further waterproofness!!!

Let the games begin!!

Test piece after the boiling/freezing. Glue  intact and edge still smooth!!

Having determined that the plywood was suitable, I could move onto making the frames. The "plans" that Dave Gentry provides are simply a set of offsets (measurements) to make the frames. In the image below you will see these offsets. (I purposely blurred the numbers. If you want them you will have to contact Dave yourself).  This was just a test run of frame #3 marked (with an an extra 1" added to the masik - an idea later abandoned) and cut from plywood underlay - not suitable for boat construction.

Below is marking out on the "real McCoy" Notice the fine surface on the wood. It is like this on both sides - which means no splintery and  knotty side on the other!!

The first frame I cut is #3 or the masik. This frame is located right under the front of the cockpit rim. You will see that the height of the frame is 10". Add on another 1/2" for the deck stringer and that is the total height of this boat.  Obviously your feet have to fit through this opening which is a mere 7" high. I'll have to rejig the deck height at the footbrace - frame #2 (thanks to size 12 shoes) but it should work out fine!! It's going to be snug, though!! The boat should be 21" wide.

Partially completed frame #3.
I'm telling myself that I will not pull a blitzkrieg on this build - like I did with my last boat. There's a lot less work and because there's no urgency to complete the boat nor the contraints of working with epoxy, I'm looking forward to a more leisurely building pace. For the record, the first frame took about 2 hrs to complete (loft and cut) but the next one's will probably take half that time!!

Of course, the time frames may be all moot. My polyester fabric left San Francisco enroute to Canada on June 12th. With the current strike, gawd knows where it is and when it'll get to me!!!!

Thanks for dropping by!!!

1 comment:

  1. from the picture of the frame in your earlier post there looks to be a half-dozen of these frames - a day's work? Add in the bow and stern and the horizontal members and I expect (knowing you) you could have your boat framed up by the end of the weekend if you wanted to... you 'da man, Sean.