"Dave W" wrote in message ...
I have used a joint that Dynamite Payson developed. It calls for making a
butt joint by scarfing both sides of the stock and using epoxy/glass for the
joint. Lay the pieces on a flat surface in position. Mark the length of
the scarf on both ends. Grind half way through both pieces where they meet
and tapering to nothing at the ends of the scarfs.

You don't have to taper it down that far. I just take the pieces
temporarily end to end and belt sand down about 30% of the way through
the pieces (6mm-1/4" material) making a slight trough about 4-5" wide,
lay in a couple of layers of fiberglass tape, say 6 oz, fill with
resin, and cover it with a sheet of wax paper to cure, flip and repeat
on the other side of the board. (note: it is easier to wet the
fiberglass material before laying it on the part, soak the part good
first too. Remember, it is easier to draw goo up through cloth, than
drive goo down into air under cloth I have even used a couple of
layers of 3.5oz tight weave right on the outside of the wood, both
sides, putty in the edges, paint. Although the joint you make has a
"bulge", it will also tend not to bend there. So when you bend the
part around the frames, the flatspot has a nice "bulge" to fair right
in and paint over... Hope that makes sence, it is the easiest of all
but should not be done without the advice of the designer.
Scotty


This results in a
shallow vee spanning both pieces. Fill the vee with glass cloth, roving and
epoxy. When set, grind the epoxy surface flat. Now, carefully turn the
assembly over and make another vee just like before. Fill vee as on the
other side. This makes a very strong joint and if done carefully is not
detectable (if painted). Email me if the method is not clear.
Dave
"Chalatso" wrote in message
. ..
Graduating to my first multi-sheet stitch-n-glue... butt joints with
blocks
are ugly, scarfing will throw off my sheet layout. Can I use a plain butt
joint, supported on both sides by glass and epoxy?

Chuck

About fiberglass splices.
Payson and Carnell miss an important point. They use plain woven glass
in which half of the fibers run paralell to the seam: a complete waste
of glass and resin.
The proper way to build such a seam is with biaxial 45/45. With that
type of glass, all the fibers work and it also adds a little torsional
strength.
I don't know why that point is not understood. I mentioned it for the
1st time here 12 years ago and designers still specify the wrong type
of glass for splices and stitch and glue seams.

Jacques from bateau.com

Jacques,
THANK YOU !!

Not for this particular boat/thread, but just in general for this specific
snippet of info . . .

It 'looked good on paper' and a LOT of 'the experts' recommended it.
However, for some reason I always had a feeling in the 'back of my mind'
{from my Textile Engineering Degree ?? An article I had read ??} that
something didn't quite fit.

Regards,
Ron Magen
Backyard Boatshop

"Jacques" wrote ...
About fiberglass splices. . . .{snip} . . .The proper way to build such a
seam is with biaxial 45/45. {snip}, all the fibers work and it also adds a
little torsional strength.

(Jacques) wrote in message om...
About fiberglass splices.
Payson and Carnell miss an important point. They use plain woven glass
in which half of the fibers run paralell to the seam: a complete waste
of glass and resin.
The proper way to build such a seam is with biaxial 45/45. With that
type of glass, all the fibers work and it also adds a little torsional
strength.
I don't know why that point is not understood. I mentioned it for the
1st time here 12 years ago and designers still specify the wrong type
of glass for splices and stitch and glue seams.

Jacques from bateau.com

With all respect and understanding of your considerable advantage in
experience and education, I question.
I think that they missed no point, as if done as reccomended, most of
these joints and seams have at least two layers of cloth on either
side creating an area that is much stronger than the material it holds
to. If designed and built correctly I think the cloth is actually
overkill, so the biax may even be more overkill. Granted, your theory
is spot on as to the strengh of the two in lamination but I don't
think it is necessary in standard construction in smaller "typically
engineered" stitch and tape boats.
Now, I have seen plans out there that only use one layer or even none
with epoxy, I consider those inferior and somewhat lazy...
Scotty, who will consider telling you who I am after Jaques makes me
look like a noobie..

(Backyard Renegade) wrote

I think that they missed no point, as if done as reccomended, most of
these joints and seams have at least two layers of cloth on either
side creating an area that is much stronger than the material it holds
to.

We are each correct in the sense that the weaker woven tape is often
sufficient for small boats seams.
As you write, as long as the joint is stronger that the parts, we are
OK.
For small boats, we often specify woven tape for the chine, keel and
bow seams because:
- it is sufficient
- it cost less
but for fiberglass splices, I prefer to alwasy use biaxial.

Now, if you build the whole boat with woven tape and need only 3 feet
for a splcie, it makes sense to stick to the woven tape that is
available.
For larger boats or, if I want a perfect job, I will not take that
shortcut.

(Jacques) wrote in message . com...
(Backyard Renegade) wrote

I think that they missed no point, as if done as reccomended, most of
these joints and seams have at least two layers of cloth on either
side creating an area that is much stronger than the material it holds
to.

Jaques
We are each correct in the sense...


How typically "Jaque'esqe"... You must be tough to work with, not that
I would pass up an opportunity. Let's all remember though, we are
still talking a two sheet canoe
Scotty

(Jacques) wrote in message om...
About fiberglass splices.
Payson and Carnell miss an important point. They use plain woven glass
in which half of the fibers run paralell to the seam: a complete waste
of glass and resin.
The proper way to build such a seam is with biaxial 45/45. With that
type of glass, all the fibers work and it also adds a little torsional
strength.
I don't know why that point is not understood. I mentioned it for the
1st time here 12 years ago and designers still specify the wrong type
of glass for splices and stitch and glue seams.

Jacques from bateau.com


I would ammend my question with the note that I was speaking, as was
the origional poster, to small, non planing, people powered hulls.
Scotty, knows his spelling and punctuation are outrageous.

Right on. In addition, the 45/45 biax is built from 2 layers of
unidirectional glass. This is stronger than a normal weave where the yarn
passes over and under other yarn throughout the material ...this naturally
puts a cutting force across the yarn and consequently unidirectional layers
in biax (etc) can take more tension before failing.

Brian D

--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project
http://www.advantagecomposites.com/catalog -- Discounted System Three
Resins products


..
"Jacques" wrote in message
m...
About fiberglass splices.
Payson and Carnell miss an important point. They use plain woven glass
in which half of the fibers run paralell to the seam: a complete waste
of glass and resin.
The proper way to build such a seam is with biaxial 45/45. With that
type of glass, all the fibers work and it also adds a little torsional
strength.
I don't know why that point is not understood. I mentioned it for the
1st time here 12 years ago and designers still specify the wrong type
of glass for splices and stitch and glue seams.

Jacques from bateau.com