clamping the centerboard case sides together

With a record cold front on it's way to the Pacific Northwest, what is beginning to become the port side centerboard case is nice and warm inside the main bridge deck cabin. Notice  that the little 750W heater has kicked itself off and it is not having to work too hard to keep things tropical inside.  Outside, the first winters snow is beginning to fall on the metal roof of the shop. 

joining the centerboard cases sides

  To control the precise distance between the centerboard case sides, I've wrapped a 4 x 6 inch wood with tape so that I can use this as an internal spacer.  Next, the plan will be to lay glass and epoxy over the  spacer, add foam along the ends and clamp the centerboard sides in place. Once the epoxy cures. I'll remover the spacer.


Setting up the boards for some hand shaping

Here I am preparing to hand shape one of the centerboards. The Oregon sun was low and strong on this 2nd of December and in honor of such a beautiful day, I decided to set things up outside.

You'll notice the recessed spar which will be covered with 15 layers of 12 inch wide uni glass in between  two layers of 24 oz triaxial glass. Since the final external dimensions will be critical,  it will take a bit of skill to shape these blanks while taking into account the required schedule of glass. Not only will I need to achieve the perfect foil section, I'll need to be able to do that by anticipating the thicknesses of individual layers of glass that will be layed in various places throughout the board.  for example; the leading edge of this board will be covered with additional layers of glass so I'll need to create a recessed leading edge so that it can be built up and fared to the correct external final shape.....it's sort of like trying to work backwards in time.


checking the fit...

OK, since I had to cut the spar out of my blank, shape it, impregnate and glass it with epoxy then bond it back in, Here's the board blank with the spar core pressed into it's home again. Next step will be to bond it back in place using a good thick mixture of micro / cabosil and epoxy.

Tomorrow I'll have a go at these blanks with a power planer and shape them like two big long boards. That will make for a good day.......maybe I'll add a fin box and take one to the Oregon coast for a surf session. or....maybe mount a mast base and windsurf it here in the Columbia Gorge.....or give it to by buddy Cory to do some free style strapless kite boarding with it.......

de bagging the centerboard spars

Here's an interesting way to open a vac. bag.....

Fitting the centerboard spars

Originally, I created my centerboard blanks with the high density cores  (mahogany spars)  all in one. but I decided to laminate, shape then wrap the spar cores individually with glass, then insert them into my centerboard blanks before the final shaping.   Fortunately, I was able to utilize a good portion of my excess foam "cut offs" to create the centerboard blanks by cutting the smaller  foam  pieces into strips and vac bagging them all together.  Notice the board blank on the left is being fitted with the spar.  


a simple post cure oven

so here's a quick post cure oven that I put together to cure my centerboard cores. tomorrow I'll pop them out of the bag and you'll be able to see what this is all about. I placed both spars inside this foam box and used small blocks of styrofoam to close in the edges between two thick foil covered foam sheets. Notice the heater in place as well as the vacuum pump sucking away.

Centerboard spar cores

After laminating, planing, shaping and tapering the centerboard spars, I am preparing to glass them and insert them back into the centerboard blanks.  In this case, I chose to use a light weight mahogany core material as my "high density" spar core.  Once these spars are embedded into the centerboards and laminated with 15 layers of 12 oz unidirectional glass,  these spars will become the primary structural elements in the centerboards.  Here, I am simply pre fitting my glass in preparation of vac bagging the glass onto the cores.  In this case, I used 3M 77 spray adhesive to keep my glass in place then I mixed a whopping amount of epoxy and rolled it on thick.  I then wrapped the spars with peel ply and vac bagged them to insure that I would get good saturation and bond between the wood and glass.  If I do this right, the wood will never know it is part of boat.  ( Being fully encased in glass and epoxy,  hopefully this wood core spar  will never see one molecule of H20 as long as I sail )