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Re: Strip: Butt joint issues?
By:Bill Hamm
Date: 12/29/2010, 8:28 am
In Response To: Strip: Butt joint issues? (Darel)

: Hi all,

: After 3 months of work I'm finally laying my first strips on a Fire
: Star.

: I quite literally found it impossible to find full-length lumber.
: Local, internet, you name it. There was one possibility that
: would have doubled the cost of the project.

: So, I decided to scarf boards together as suggested in Rob's plans.
: Built the jig, and also built a clamp jig to hold them square
: and tight while drying. Did a couple boards at an 8:1 scarf.
: Glued them up with TB III and let them dry for a week.

: As soon as I picked them up they broke at the joints. All of them.
: The one that didn't break, when I ran it through the table sw
: each individual strip broke as it came off.

: After much searching, I figured butt joints would have to do. To my
: (admittedly faulted) logic, the end result is the same product.

: Sidebar: when I design and build things there are always
: compromises. As a matter of habit I generally try to turn my
: compromises into "design elements".

: One idea I had for a design element would involve lining up all of
: my butt joints in a line from shear down about 4". My
: (admittedly faulted) logic tells me this is not a good idea for
: structural reasons. A little voice also tells me that most of my
: strength comes from glass.

: Question #1: Will lining up these butt joints create a weak
: "seam" in the finished kayak? Like, will it break in
: half when I pick it up? Strap it to a car?

: I laid my sheer line to see what it looked like. I like it. What I
: did was cut several 2" pieces of strip and (permanently)
: glued them to the back of the butt joint. I can either sand
: these off or leave them in place and glass over them. Question
: #2: Thoughts? Leave in place? Sand off? Will they actually do
: anything to reinforce the joint? I rounded off the corners so
: they look like little pills and I think I could live with them
: in the finished boat if they do actually do anything.

: Like I said the line of butt joints will be from the sheer line
: about 4" down. There will be hardwood pinstripes running
: between the butt-jointed strips. No more than 3 butt joints will
: be lined up without a hardwood pinstripe between them. Does this
: help any?

: Anyone have any thoughts? Bill, I know you have no issues with butt
: joints. Rob, it's your kayak and I know you DO have a problem
: with butt joints. Anyone feel like chiming in? I don't want to
: do anything that will compromise the integirty of my kayak.

: Thank you,
: Darel

Btw, the problem of using butt joints on the boat, was mentioned by someone else, is they don't bend the same as a full length strip so you can get bumps where the strips join. I solve this using a backing block behind each butt joint, just a tiny piece of strip, maybe 2" long, that's hot glued in place (as little glue as will hold) to hold the strips in plane with each other. These have to be popped off when you do the inside of the boat later on. Prying them usually will break the joint with little wood loss, unless you use a bunch of hot melt glue, then it'll pull wood loose. This would be far more difficult if the joints were all lined up btw. Problem pieces that won't pop off can be ground off with course grit on your sander.

Btw, if you don't use hot glue to put the butt blocks on it's a heck of alot more work to finish the inside of the boat.

I suppose this my method is about the same amount of work as scarfs, but works ok for me.

Bill H.

Messages In This Thread

Strip: Butt joint issues?
Darel -- 12/28/2010, 10:03 pm
joints of many kinds *PIC*
Paul G. Jacobson -- 1/2/2011, 12:02 pm
Re: Strip: Butt joint issues?
Fred Gasper -- 12/30/2010, 7:57 am
Re: Strip: Butt joint issues?
Paul G. Jacobson -- 12/30/2010, 11:54 am
Re: Strip: Butt joint issues?
G New -- 12/29/2010, 8:07 pm
Re: Strip: Butt joint issues?
Eric -- 12/29/2010, 7:14 pm
Re: Strip: Butt joint issues?
Rob Macks / Laughing Loon CC&K -- 12/29/2010, 2:16 pm
Re: Strip: Butt joint issues?
Dean -- 12/29/2010, 12:40 pm
Re: Strip: Butt joint issues?
Joy -- 12/29/2010, 9:43 am
Butt joints NOT over forms are bad
Paul G. Jacobson -- 12/29/2010, 1:43 pm
Re: Butt joints NOT over forms are bad
Al Edie -- 12/30/2010, 12:06 pm
Re: Butt joints NOT over forms are bad
Bill Hamm -- 12/30/2010, 1:48 pm
Re: Butt joints NOT over forms are bad
Bill Hamm -- 12/29/2010, 3:02 pm
Re: Strip: Butt joint issues?
Randy Echtinaw -- 12/29/2010, 10:56 am
Re: Strip: Butt joint issues? *PIC*
Joy -- 12/29/2010, 10:09 am
Re: Strip: Butt joint issues?
Bill Hamm -- 12/29/2010, 8:28 am
Butt joint boards or strips? *PIC*
Jay Babina -- 12/29/2010, 8:19 am
Re: Butt joint boards or strips?
Bill Hamm -- 12/29/2010, 8:30 am
Re: Strip: Butt joint issues?
Bill Hamm -- 12/29/2010, 8:07 am
Re: Strip: Butt joint issues?
Les Cheeseman -- 12/29/2010, 5:03 am
Re: Strip: Butt joint issues?
Randy Echtinaw -- 12/29/2010, 7:00 am
Re: Strip: Butt joint issues?
Darel -- 12/29/2010, 5:36 am
Still got that bottle of glue?
Paul G. Jacobson -- 12/31/2010, 7:22 am
Re: Still got that bottle of glue?
Darel -- 12/31/2010, 11:31 am
buy new glue
Paul G. Jacobson -- 12/29/2010, 4:27 am
Re: Strip: Butt joint issues?
Dave Houser -- 12/29/2010, 12:46 am
Re: Strip: Butt joint issues?
JohnK -- 12/29/2010, 2:23 am
Re: Strip: Butt joint issues?
Charlie -- 12/28/2010, 11:20 pm
Re: Strip: Butt joint issues?
Bill Hamm -- 12/29/2010, 8:16 am
Re: Strip: Butt joint issues?
Allan -- 12/28/2010, 10:36 pm
Re: Strip: Butt joint issues?
Stephen Troy -- 12/28/2010, 10:13 pm
Re: Strip: Butt joint issues? *NM* *PIC*
Darel -- 12/29/2010, 12:43 am
Re: Strip: Butt joint issues?
Bill Hamm -- 12/29/2010, 8:33 am
Re: Strip: Butt joint issues?
mark j -- 12/28/2010, 11:19 pm
Re: Strip: Butt joint issues?
Darel -- 12/28/2010, 10:22 pm