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sternsailart3S.jpg (49905 bytes) Summer Breeze! - This is the story of an 11'8" long 50" beam 16" sides, 500 lb capacity skiff from two sheets of 1/4" 4x8 plywood. Award winning - She won the 2001 Duckworks design contest. 
   Butt block Skarfing:
Introduction
Getting started
Sides 
  Skarfing
Frame
Transom 
Stem
Bending
Chines
Bottom
Gunwales
Breasthook
Quarter knees
Seat
Mast Partner
Keel
Skeg
Mast & Spars
Leeboard
Rudder
Sail 
Floatation 
Painting 
Resources 

There are many ways to clamp butt block skarfs. (Scarfing is a fancy woodworking term used to describe making two shorter pieces of wood into one longer piece.) You can use weights or short #6 sheet metal screws, or even clinch bronze nails and leave them in place, but I prefer a staple gun with half inch staples. The staples are removed after the joint cures.

          Draw a center line down the butt blocks. This line will be above the joint of the ply pieces. A large flat surface is needed. It can be the floor or a table or workbench. I like to set up saw horses with a sheet of ply or OSB on some 2x4s. Use wax paper or plastic wrap to prevent gluing your pieces to the work surface.

Do a dry layout of the pieces and trim the butt blocks to clear the stem, chine logs or inwales if you plan to install them. Trace the butt blocks during the dry run. You can also round the edges and sand the blocks making them ready to paint, before gluing them.

Make sure you weight or tack your pieces so they donít slide around when they have the glue on them. Apply glue to the edges and the surfaces using your pencil trace lines as a guide. If you use PL Premium spread it with a notched trowel. If you use Titebond II you can spread it with a brush, roller or spatula or scrap of cardboard.

Position the butt blocks, drape twine over them and staple stradling the twine. A staple every couple of inches will do. Make sure you get the corners. The twine both prevents the 1/2Ē staples from going all the way through the ply and makes removal easier. I usually let my joints dry overnight.

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    Here is a tip on this scarfing method.  

 I learned this trick  while joining tops for musical instruments. Slip a small strip of wood (say a 1/2" thick) under the joining edges to hold them in a sort of tent position then clamp (or tack) both ends to your work surface. When that prop strip of wood is removed, and you flatten the "tent",  clamp pressure gets transferred inward, to the edges of the glued pieces. 

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This is a rather unconventional approach to scarfing, however if you read the fine essay by Jim Michalak on various joining systems he's used you'll see he concludes that all the systems have worked fine. He says:

"I've tried lots of different ways to make the joint in the 15 or so boats I've built
over the years. All the methods worked. I have a feeling that the butt joints on the
usual instant boat hull are not highly loaded and not too critical to overall boat
strength. "

So it appears that the stresses on these joints is not excessive. I've designed Summer Breeze so these joints occur where the bending is very gradual. If you lack my faith in PL Premium feel free to use any of the other approaches to joining wood outlined so well by Jim Michalak and others. If you decide to use PL Premium, here are some tips. 

   
 

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