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Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
By:Bill Hamm
Date: 4/8/2011, 7:45 am

: Point taken. It is an easy test, though, and overkill... if it'll
: support my weight, it'll work in the kayak.

: I did test the new joint tonight, in that fashion. I figure if it
: broke, I learned something, and I can recycle it into deck
: stringers. My two tables were about 24" apart, so I moved
: the stringer along so the joint was not hung between the tables.
: I placed the stringer so the 3/4" wide surface was against
: the table, and put my ~170 lbs of weight on it. Took it without
: a problem. Then I moved the joint to the middle of the space
: between the tables, and did the same. No problems. Then I did
: the same, placing the wide face against the table. It flexed
: more (obviously), but held my full weight, even on the joint.

: What did I do differently? Cut and planed the joint better, applied
: more Gorilla Glue, clamped it less, and cut the joint at 12:1
: slope instead of 8:1. I figure all the above helped, but the
: 12:1 slope and paying better attention to the quality of the cut
: helped the most, probably.

: I'm wishy washy as to whether I want to use a scarf joint like this
: for the gunwales. Seems to me the joint would be stronger when
: the forces applied are acting to pry the joint apart
: perpendicularly to the plane of the joint. I'd imagine the keel
: would see these forces. The gunwales, though... because they're
: already bent to form the edge of the kayak, I see the joint
: undergoing more sheer force. Using a butt block like Tom Yost
: recommends would place that force against the screws. Failure
: would require stripping the screw holes, most likely... and
: would probably require a whole heckuva force. I'm not sure how
: the GG in a scarf joint orientated the way I made it would
: handle it.

: The formers in the Sea Tour 15 EXP are 2' to 2-1/2' apart, the same
: distance between supports as my little test tonight, so you
: could say the test approximated a ~170 load against the gunwale
: between the formers. It held... but my gut doesn't like it. But,
: like you say, under normal loads the forces are distributed
: along the frame of the kayak, and the sum of those itty bitty
: stringers handles it fine.

: ERG. I think I just need to build this thing and be done with it.
: If the joints don't hold, I get to build another one, right? ;oD

: Thanks to everyone reading, posting, and helping this newbie
: through his time of need, by the way. It's one thing to research
: this for a while (It's been months, with all the obstacles of
: real life), but it's quite another to actually start doing it,
: second guessing yourself, and trying to plan ahead so you don't
: screw up too badly. *grin*

All of my SOF's have scarfed stringers/gunwales/keels. A properly done scarf is generally as strong as the wood itself and shorter lengths of wood are much less expensive. Tom doesn't recommend butt blocks, only says they can be used if you're not comfortable making scarfs. They are no where near as strong as a scarf.

Bill H.

Messages In This Thread

Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/6/2011, 8:47 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
b stupak -- 4/6/2011, 9:23 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Kudzu/Jeff Horton -- 4/6/2011, 10:47 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/6/2011, 11:22 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/7/2011, 12:49 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Brian Nystrom -- 4/7/2011, 7:01 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Kudzu/Jeff Horton -- 4/7/2011, 8:45 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Mike Bielski -- 4/7/2011, 9:10 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 10:22 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
George in Va -- 4/7/2011, 11:59 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/7/2011, 2:09 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Justin -- 4/7/2011, 10:49 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 11:34 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
StephenHJ -- 4/7/2011, 12:11 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 11:50 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
StephenHJ -- 4/8/2011, 2:12 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/7/2011, 2:11 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 7:41 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/7/2011, 8:17 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 11:28 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel *PIC*
Don T -- 4/8/2011, 12:09 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Farback -- 4/21/2011, 10:03 pm
Off Topic: Fighting Fires *PIC*
Don T -- 4/22/2011, 9:00 am
Re: Off Topic: Fighting Fires
Farback -- 4/22/2011, 1:22 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/8/2011, 7:45 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/8/2011, 8:20 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/8/2011, 9:41 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Justin -- 4/8/2011, 2:29 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/8/2011, 3:30 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
StephenHJ -- 4/8/2011, 9:07 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/9/2011, 4:35 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Dan Caouette (CSFW) -- 4/9/2011, 7:26 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/9/2011, 8:14 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/9/2011, 8:18 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Dan Caouette (CSFW) -- 4/9/2011, 10:10 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/10/2011, 12:18 am
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel *PIC*
Tom Yost -- 4/7/2011, 3:44 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel *PIC*
Alan Kepler -- 4/7/2011, 4:16 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Alan Kepler -- 4/7/2011, 4:19 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 10:43 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Justin -- 4/7/2011, 7:49 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Bill Hamm -- 4/7/2011, 8:23 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 10:34 pm
Re: Skin-on-Frame: Scarfing Stringers/Gunwale/Keel
Noel Bennett -- 4/7/2011, 10:50 pm
Scarf better than butt in my test
Kocho -- 4/10/2011, 9:16 pm
Re: Scarf better than butt in my test
Kocho -- 4/10/2011, 9:21 pm
Re: Scarf better than butt in my test
Noel Bennett -- 4/10/2011, 10:41 pm
Re: Scarf better than butt in my test
Bill Hamm -- 4/11/2011, 12:37 am
Re: Scarf better than butt in my test
ancient kayaker -- 4/11/2011, 12:15 pm
Re: Scarf better than butt in my test
Bill Hamm -- 4/11/2011, 1:31 pm
Re: Scarf better than butt in my test
ancient kayaker -- 4/11/2011, 6:51 pm
Re: Scarf better than butt in my test
Bill Hamm -- 4/12/2011, 1:13 am
Re: Scarf better than butt in my test
Noel Bennett -- 4/10/2011, 10:30 pm
Re: Scarf better than butt in my test *PIC*
ancient kayaker -- 4/12/2011, 12:34 am
Re: Scarf better than butt in my test
Bill Hamm -- 4/12/2011, 1:15 am
Re: Scarf better than butt in my test
ancient kayaker -- 4/12/2011, 2:29 pm
Re: Scarf better than butt in my test
Bill Hamm -- 4/13/2011, 12:50 am
Re: Scarf better than butt in my test
ancient kayaker -- 4/13/2011, 11:17 am
Re: Scarf better than butt in my test
Bill Hamm -- 4/13/2011, 1:51 pm
Re: Scarf better than butt in my test
Kirk Fredericks - Farback Carpentry and Automation -- 4/13/2011, 3:34 pm