[bolger] Re: Michalak butt joints
jmbel-@...wrote:
My windsprint has the 4" wide plywood butt blocks hel in place by epoxy
only and a strip of 6 oz FG tape on the outside. Works well. I tried to
clinch the nails as specified by Payson but like you I found it was a
mess. So, I pulled them.
My other boat has a piece of lumberyard 1x4 as butt blocks. They are
glued with epoxy and secured with brass screws. This was what was
recommeded by Michalak in the plans. It didn't tape anything in the
butt, but the outside of this boat is glassed. Again, no problems. It
does make more of a flat spot on the topsides than a thinner butt block
might.
JB
original article:http://www.egroups.com/group/bolger/?start=212
My windsprint has the 4" wide plywood butt blocks hel in place by epoxy
only and a strip of 6 oz FG tape on the outside. Works well. I tried to
clinch the nails as specified by Payson but like you I found it was a
mess. So, I pulled them.
My other boat has a piece of lumberyard 1x4 as butt blocks. They are
glued with epoxy and secured with brass screws. This was what was
recommeded by Michalak in the plans. It didn't tape anything in the
butt, but the outside of this boat is glassed. Again, no problems. It
does make more of a flat spot on the topsides than a thinner butt block
might.
JB
original article:http://www.egroups.com/group/bolger/?start=212
> I was looking at Jim Michalak's site and his essay on plywood butt
> joints. Thinking about using his joint in the sides of the folding
> schooner. The plans call for an 8" plywood butt plate glued and
> fastened with clinch nails. I did the clinch nails on the Gypsy and
> they never did finish out neatly. Wondering about using screws, epoxy
> and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
> made tape joints for the six hour canoe we built. They have worked
> well but it was finicky and as Jim says it is hard to get everything
> perfectly flat and smoothed out. Taping the outside face of the side
> panels after they are in place looks a lot easier to me. What do you
> think?
> Leander
>
I just built featherwind using Dave Carnell's glass tape only butt
joints and found it pretty straight forward. I tested all the trimmed
strips for strength and none broke the joint - rather the ply to either
side.
David
harding2@...wrote:
schooner. The plans call for an 8" plywood butt plate glued and
fastened with clinch nails. I did the clinch nails on the Gypsy and
they never did finish out neatly. Wondering about using screws, epoxy
and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
made tape joints for the six hour canoe we built. They have worked
well but it was finicky and as Jim says it is hard to get everything
perfectly flat and smoothed out. Taping the outside face of the side
panels after they are in place looks a lot easier to me. What do you
think?
Leander
Simplicity Boats (mirror sites - if one doesn't work...)
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http://members.xoom.com/simpleboats/
Here's my latest boat:
http://members.tripod.com/simplicityboats/featherwind.html
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joints and found it pretty straight forward. I tested all the trimmed
strips for strength and none broke the joint - rather the ply to either
side.
David
harding2@...wrote:
>joints. Thinking about using his joint in the sides of the folding
> I was looking at Jim Michalak's site and his essay on plywood butt
schooner. The plans call for an 8" plywood butt plate glued and
fastened with clinch nails. I did the clinch nails on the Gypsy and
they never did finish out neatly. Wondering about using screws, epoxy
and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
made tape joints for the six hour canoe we built. They have worked
well but it was finicky and as Jim says it is hard to get everything
perfectly flat and smoothed out. Taping the outside face of the side
panels after they are in place looks a lot easier to me. What do you
think?
Leander
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Simplicity Boats (mirror sites - if one doesn't work...)
http://members.tripod.com/simplicityboats/
http://members.xoom.com/simpleboats/
Here's my latest boat:
http://members.tripod.com/simplicityboats/featherwind.html
Quasi esoteric musical instruments
unicornstrings.com
bianc-@...wrote:
Leander,
there's a lot of info around on plywood backed butt joints, but not
always coherent. I have two books treating the matter rather
extensively, i.e. "BOATBUILDING WITH PLYWOOD" by Glen L. Witt and "A
MANUAL OF MODERN SMALL PLYWOOD BOAT CONSTRUCTION TECHNIQUES" by Paul
Fisher.
Witt gives the following guidelines:
1)use screws (nails only on the smallest boats) on 2" centers,
staggered;
2)the width of the backing plate should be 15 times the thickness of
the plywood.
He says that this butt joint is as strong as a scarfed joint.
Fisher gives indications on how to avoid the flat bump: use a 4"-5"
wide back plate for 1/4" ply, 6" for 3/8", 8" for 1/2".
Dave Carnell is a strong advocate of FG splices and details the matter
in his web pagehttp://home.att.net/~DaveCarnell/.
I'll use FG splices for my Micro. Best, Pippo
original article:http://www.egroups.com/group/bolger/?start=212
Leander,
there's a lot of info around on plywood backed butt joints, but not
always coherent. I have two books treating the matter rather
extensively, i.e. "BOATBUILDING WITH PLYWOOD" by Glen L. Witt and "A
MANUAL OF MODERN SMALL PLYWOOD BOAT CONSTRUCTION TECHNIQUES" by Paul
Fisher.
Witt gives the following guidelines:
1)use screws (nails only on the smallest boats) on 2" centers,
staggered;
2)the width of the backing plate should be 15 times the thickness of
the plywood.
He says that this butt joint is as strong as a scarfed joint.
Fisher gives indications on how to avoid the flat bump: use a 4"-5"
wide back plate for 1/4" ply, 6" for 3/8", 8" for 1/2".
Dave Carnell is a strong advocate of FG splices and details the matter
in his web pagehttp://home.att.net/~DaveCarnell/.
I'll use FG splices for my Micro. Best, Pippo
original article:http://www.egroups.com/group/bolger/?start=212
> I was looking at Jim Michalak's site and his essay on plywood butt
> joints. Thinking about using his joint in the sides of the folding
> schooner. The plans call for an 8" plywood butt plate glued and
> fastened with clinch nails.
On my Tennessee, I used ply butt plates, and epoxied them on. Later they
opened up on the outside, so I went back and taped the crack. Right now, I
am building Jim Michalak's Jonsboat, and I am just using tape. So far it
seems pretty easy. I used a disk sander to make a shallow cove at the
joint, then glassed with tape cut on a bias. When I sanded the extra down
with a belt sander, I discovered some low spots, so I glassed again. That
seemed to do it.
Chuck
opened up on the outside, so I went back and taped the crack. Right now, I
am building Jim Michalak's Jonsboat, and I am just using tape. So far it
seems pretty easy. I used a disk sander to make a shallow cove at the
joint, then glassed with tape cut on a bias. When I sanded the extra down
with a belt sander, I discovered some low spots, so I glassed again. That
seemed to do it.
Chuck
> I was looking at Jim Michalak's site and his essay on plywood butt
> joints. Thinking about using his joint in the sides of the folding
> schooner. The plans call for an 8" plywood butt plate glued and
> fastened with clinch nails. I did the clinch nails on the Gypsy and
> they never did finish out neatly. Wondering about using screws, epoxy
> and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
> made tape joints for the six hour canoe we built. They have worked
> well but it was finicky and as Jim says it is hard to get everything
> perfectly flat and smoothed out. Taping the outside face of the side
> panels after they are in place looks a lot easier to me. What do you
> think?
> Leander
>
>
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I was looking at Jim Michalak's site and his essay on plywood butt
joints. Thinking about using his joint in the sides of the folding
schooner. The plans call for an 8" plywood butt plate glued and
fastened with clinch nails. I did the clinch nails on the Gypsy and
they never did finish out neatly. Wondering about using screws, epoxy
and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
made tape joints for the six hour canoe we built. They have worked
well but it was finicky and as Jim says it is hard to get everything
perfectly flat and smoothed out. Taping the outside face of the side
panels after they are in place looks a lot easier to me. What do you
think?
Leander
joints. Thinking about using his joint in the sides of the folding
schooner. The plans call for an 8" plywood butt plate glued and
fastened with clinch nails. I did the clinch nails on the Gypsy and
they never did finish out neatly. Wondering about using screws, epoxy
and a 1/8 for backing as per Jim's essay. Would it be too stiff? We
made tape joints for the six hour canoe we built. They have worked
well but it was finicky and as Jim says it is hard to get everything
perfectly flat and smoothed out. Taping the outside face of the side
panels after they are in place looks a lot easier to me. What do you
think?
Leander