Monday, April 12, 2010

Spinning my Wheels

The frames are built, the strongback is assembled, the chines are 80% done, and now I need a bunch of things to move forward. 

First on the list is wood for the stem and transom.  The plans call for white oak for the stem and mahogany for the transom.  The stem is 2 1/4" wide, or 10/4 material....a look at the local hardwood vendors proves to be fruitless for anything that thick as a single piece, some guys have some 8/4 but that just won't do.  So the only choice is to glue up two or three pieces to get what I need, the problem is that oak is not a good candidate for gluing with expoxy because of the high tannins levels.  This leads to a long investigation into the merits of the various glues that are appropriate for below the water line useage.  Turns out that the choices are limited to epoxy and resorcinol. 

Resorcinol is the glue that is used to make marine grade plywood and what everyone complains about is the dark glue that it leaves and the fact that it is not a gap filling glue, in fact the surfaces need to be well-mated and clamped for the glue to do its stuff.  On the positive side it can be used with oak and no one has any horror stories to tell about failing joints--even after 20 years.

Okay I'm in, resorcinol it is then.  Here comes the spinning my wheels part...turns out that resorcinol is not easily available around here so now I'm back to square one.  But a little more knowledgable on glue!

Decided to try out a local hardwood wholesaler called PJ White that I had heard will sell retail also.  Turned out to be a good move, as I was pulling up to the yard I see a guy driving a fork lift with 8-10pcs of mahogany out to a contractor's truck.  Beautiful looking boards all between 10 & 14" wide, 4/4 material each board 16' long.   They carry two types of mahogany, african and honduras, african is about 1/2 the price of honduras.  Ended up buying a single 11" wide plank, 16' long with nice figure (thought it will look nice if left bright on the stern of Willy) that I cut in two with a handsaw in the yard before loading it into my Volvo wagon.

The 4/4 material turned out to be closer to 5/4 so my plan is to plane a little off one side, glue them together with epoxy and use one of the 8' mahogany boards for the stem.  I will have to find a use for the remainder of this board.  But, the price was so good from PJ's that I can't go wrong--about 30% cheaper than the other local suppliers.

Feeling pretty good about getting the wood and glue issues all resolved but then started thinking about that mahogany and wondering what the moisture content of that wood might be???  Don't have a moisture meter so I am a little resistant to start cutting it to size and thickness right away.  Besides, there are still more problems that I need to solve before I can go much further.

First on the list is to order fasteners.  The original plan was to use copper nails and burrs and silicone bronze screws.  Jamestown Distributors was the vendor of choice (seem to have the best prices) but when we went to place our order we discovered that the price of silicone bronze screws went up 80% (we were stunned!!!). 

This led to a massive internet search on the pros and cons of using either bronze or stainless steel.  Both seem to have there place in wooden boat building but the clincher for us was a post by a boat builder on Vancouver Island who was replacing the hull on his boat that spent the last 15 years in salt water and said that the stainless steel screws he was removing were all in excellent shape.  That is more than enough proof for us prairie boys that only have some fleeting hopes that our boat will get into the salt off Vancouver Island some year.

I also changed my mind and decided to use roves instead of burrs.  The nails for the roves are smaller in diameter than the nails I would have to use with the burrs and since our planking is 3/8" I was concerned that the larger holes would impact the structural integrity of the plank edges.

With all this time on my hands I decided to would be a good idea to mock up the stem and see if we really understand how to create the rabbet.  So we took a piece of spruce 2x10 and laid out the stem from our lofted pattern.  Really quite simple, we drew the stem up on a piece of 1/4" ply so we just put some nails through the key points along the perimeter and then using a batten re-drew the stem on the 2 by.  

Once we had the rabbet line and the bearding line (following the instructions from the "Boat Builders Apprentice") in place we made a fid (a fancy name for a piece of wood the same dimensions as your planking) we starting working away at chipping out the rabbet with our chisels.  

When we put the stem into place we were pleased and a little surprised to see that our rabbet was good ( a little rough but passable).  

All that chipping with a hammer led to another project--making a proper wooden mallet.  Found a great plan by Diego de Assis that provides all the proper dimensions --

I made mine from some scrap maple and consequently built the head up out of 3 layers rather than the single piece that Diego uses.  If you decide to build yours this way here are a couple of pointers that will save you some head scratching.  

1. Use an adjustable square to set the angle of the handle and the insides of the center mallet head pieces.  Once you set this angle you can easily lay out all these pieces and then cut them.
2. Glue up the head in sections, position and glue center head pieces (2) to one of the side pieces and let it cure.  Then glue the other outside piece in place. It is much easier to build it up in phases rather than dealing with a slimey, moving mess of all 4 pieces at once.

So far I have been really impressed with how well this tool works.  At first I thought the angle on the head might we too much but after using it for a while I can tell you it is perfect!


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