Joint methods

Has anybody tried other methods of joints then scarfing (i.e., finger joint or dovetail)? How did they work for you?

 

For wood or plywood?

 

For Stich & Glue plywood kayaks

 

You'll find the scarf is the best bang for the buck when edge joining plywood. Dove tails are nice, pretty things but hard to do on the edge of a sheet of ply with half of the grain running the wrong way. Plywood gets it's strength from the laminations of cross grain, this also makes it very stable. You'd defeat this trait if you routed out a tapered groove or tail on the edge. You'd also not have much gluing area in the joint and create a "hard spot" when trying to bend a fair curve with joined pieces. There are areas where both joints you've mentioned could be used, but the scarf is one of the best joints around. With a jig and well thought out planning they go together fine.

It takes some practice and setup to get the knack of them, but well worth the effort. Finger joints look like crap to my eye anyway . . .

 

I agree with all PAR says. However you seem to be seeking any easier alternative to a scarf joint. Try a butt joint, it is much quicker and easier. Make sure the overlap is right not too much not too little. Use epoxy. Accept a hard spot.
briany

 

What are you scarfing?

 

The butt joint is a poor substitute for the scarf, but can be made to suffice . . .

 

joints

Barbour Boat Works used butt-blocks in all of their boats from 1937 until production ceased in 1964.I restore these boats and am amazed that they hold up so well before the advent of high tech glues.The block usually consisted of a 5 or 6 inch piece of mahogany attached with well patterned screws(usually 8).I have no problem with butt-joints/blocks.

 

Is ther any reason not to use a half lap, as this would be a very simple set up with a router and straight bit?

 

I only use the ship's lap (half lap) for interior joinery, no topside or below waterline exposure. It's a poor man's joint, worth little compared to others and near as difficult to make to hold back water, so why bother.

If you can use a router and straight bit you can make a scarf, which is a much better joint, hands down.

Pungolee, the butt joint is for folks who don't have to bend stock around a boat. The butt can be made tight, but will create a hard spot on the material that can't be bend in the same fair curve as the rest of the material being used. It's a common repair technique, being down and dirty, quick to install, but I've seen little to beat a scarf to do the same task, show little to no repair in the area and offer the same material qualities.

Having just finished scarfing in 26 different frame repairs to a lapstrake powerboat with steam bent ribs. The owner (a life long wooden boat owner) couldn't find the repairs on the ribs in question, just before I planked her up. This is a testament to the type and quality of repair a scarf makes. Not only stronger, but easily hidden amongst the framing, because of the seamless nature of the repair. Try that with a sister or butt block and it'll stick out like a sore thumb.

 

JosephKeel,

You got replies and how and what. I would like to know which jointing methode you used and did it work?

Peter