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If Schroedinger started with a dead cat . . .
By:Paul G. Jacobson
Date: 9/10/1999, 5:51 pm
In Response To: Re: Simply put . . . (daniel)

> But it's also true that "a chain is only as strong as its weakest
> link".

Even a weak chain can be stronger than a clothesline.

And if you use two chains they will share the load. Maybe the weakesk link will give out at 50 pounds. It is still strong enough to hold a 1 pound load for an eternity. We are talking overkill here.

If the boat breaks you will probably patch it by using duct tape. And the repair will probably last for weeks. Anything stonger than that will simply last longer. Butt or scarph joint -- or half lap, or clinker nailed joint -- once you embed these things between two layers of glass cloth and polyester or epoxy resin you have a reinforced joint that is far stronger than the original materials.

> Bram makes a good point, though: there IS one very good reason for using
> one over the other -- aesthetics. A scarf may be nearly invisible, where a
> butt might be quite visible. I hadn't been thinking along those lines at
> all.

I use butt joints in strip building, with the exception of about 7 strips that I scarph to make full length or longer. I use these as my starting pieces and I move them over the forms to make sure things are fair and properly situated before I put on the rest of the strips. I find that the ends of most of my pieces of wood are slightly discolored, so I may cut off a 1/4 to 1/2 inch from the ends of some strips to get a neat edge. I do see some light through these areas when the boat is over my head as I am carrying it to launch or cartop it. Big deal. If I disliked theis I could cut the strips at a 45 degree angle, which is not enough taper to qualify as a scarph, but it would make it more difficult to see through the joint. A half lap joint would probably be easiest to do. Set up a router table to cut the lap. No light shining through, plenty of glue surface, self aligning (if you cut it well) and only a thin joint line.

Butt, 45 degree cut, or scarph -- it makes no difference -- you will have a vertical line where one piece of wood ends and the next begins. if you are sloppy with a butt joint this will be wider, as it will soak up some glue in the end grain on the strips and appear a bit darker. Actually, this pattern dowe not bother me in the least. I have a very nice hardwood floor in my home, and ALL the pieces of wood butt together. The pattern is delightful.

> While this may be true for a strip-built, it's not true for a stitch&glue,
> correct? don't all the butt joints generally line up at midspan?

They shouldn't, but they might. If youscarph your plywood before cutting it, since the different pieces are a different length overall, you can cut them so the joints are staggered. On the other hand, you can make a boat that comes apart into two more more pieces. ALL the seams will be in a line, but the boat will still be strong enough for use, as the joint is supported on the inside by additional material.

> [ by the way, I'm not really hung up on this issue... just toying with the
> problem as a thought experiment... "Schrodinger's Kayak", say.
> :)

If Schroedinger had started with a dead cat . . .

> I've gotta have SOMEthing to do for the next couple months until I get
> this dang wedding out of the way (mine, that is) and have some free time
> to start building my 'yak. :) ]

Consider having your appendix removed. That will use up a week or two of your time. At least that has been my experience over the last two weeks. Congratulations on your upcoming wedding. Weddings are far less painful than surgery. In the meantime, read up on tech manuals on epoxy resin (West Systems has a nice set) and re-read the instructions and details on your building plans. Everytime you go through it you'll find somethng new. when you start to assemble things you'll have the concepts memorized and everything will go faster and more smoothly.

Best of luck to you and your fiancee on your live's voyages. Buy her a respirator and a PFD for a wedding present. Make sure both fit.

Paul G. Jacobson

Messages In This Thread

structural properties of scarf and butt joints
daniel -- 9/9/1999, 8:48 pm
Re: structural properties of scarf and butt joints
lee -- 9/13/1999, 9:22 am
Re: structural properties of scarf and butt joints
Bram -- 9/13/1999, 11:17 am
Re: test panels
lee -- 9/13/1999, 2:53 pm
Re: test panels
Bram -- 9/14/1999, 11:04 am
test swatches
Mike Hanks -- 9/14/1999, 9:49 pm
Re:subjecting test panels
lee -- 9/14/1999, 7:14 pm
Re:subjecting test panels
Don Beale -- 9/15/1999, 1:37 am
Re:subjecting test panels
lee -- 9/15/1999, 10:15 am
Re: structural properties of scarf and butt joints
Bram -- 9/10/1999, 11:35 am
Re: structural properties of scarf and butt joints
Bobby Curtis -- 9/10/1999, 9:25 am
Simply put . . .
Paul G. Jacobson -- 9/10/1999, 6:56 am
Re: Simply put . . .
daniel -- 9/10/1999, 5:07 pm
If Schroedinger started with a dead cat . . .
Paul G. Jacobson -- 9/10/1999, 5:51 pm
How Gestaltic!
Shawn Baker -- 9/10/1999, 2:39 pm
Re: The ignorant view...
Don Beale -- 9/10/1999, 12:17 am
Re: My Two-Cents
Jerry Brown -- 9/10/1999, 9:13 pm