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Ookie Wonderslug
Guest
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 Posted: Wed Jan 05, 2005 8:43 am Post subject: foam vs luan |
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What is the cheapest foam sheeting that one can buy that will not
melt when you apply polyester resin to it? What is the best source for
this foam? How much does it cost? Would it better than using luan as a
core?
I need a bigger jon boat. Mine is 40 years old and starting to fall
apart. I am going to build one, but money is a deciding factor in
this. If I had the cash, I would just go to Outdoor World and buy one
of theirs for $500. But since I don't have that kind of green I guess
I can build one. I would like to use foam as a core because it is
light and easy to form. I could see glueing a boat together out of 1/2
or 3/4 inch sheet foam and then glassing it. It just feels like it
would be easier than building a frame and then attaching the luan and
then glassing that. However I have never built a boat. I have rebuilt
a couple, but never built one from scratch.
Any advice? Pointers? Suggestions? |
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MMC
Guest
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| Posted: Wed Jan 05, 2005 6:18 pm Post subject: Re: foam vs luan |
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Do a google search for "stitch and glue".
"Ookie Wonderslug" <ookie@my-deja.com> wrote in message
news:isnmt01ts1dhqr47eg8rf9geocmcst1l6q@4ax.com...
| Quote: | What is the cheapest foam sheeting that one can buy that will not
melt when you apply polyester resin to it? What is the best source for
this foam? How much does it cost? Would it better than using luan as a
core?
I need a bigger jon boat. Mine is 40 years old and starting to fall
apart. I am going to build one, but money is a deciding factor in
this. If I had the cash, I would just go to Outdoor World and buy one
of theirs for $500. But since I don't have that kind of green I guess
I can build one. I would like to use foam as a core because it is
light and easy to form. I could see glueing a boat together out of 1/2
or 3/4 inch sheet foam and then glassing it. It just feels like it
would be easier than building a frame and then attaching the luan and
then glassing that. However I have never built a boat. I have rebuilt
a couple, but never built one from scratch.
Any advice? Pointers? Suggestions? |
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William R. Watt
Guest
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| Posted: Wed Jan 05, 2005 7:02 pm Post subject: Re: foam vs luan |
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Plywood would be cheaper, lighter, and easier to build.
Like the fellow wrote "stitch and glue", also called "stitch and tape".
A cheaper building method is chine batten construction which uses strips
of wood along the seams instead of resin putty.
The foam boatbuilding I've seen described requires a building frame to which
a special boatbuilder's foam is attached. It's then covered on the outside
with lots of fibreglass for strength. Then it's femoved from the bulding
frame, turned over, and covered on the inside with more fibreglass. All
that fibreglass makes it heavy.
--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned |
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Jonathan W
Guest
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| Posted: Wed Jan 05, 2005 8:04 pm Post subject: Re: foam vs luan |
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William R. Watt wrote:
| Quote: | Plywood would be cheaper, lighter, and easier to build.
Like the fellow wrote "stitch and glue", also called "stitch and tape".
A cheaper building method is chine batten construction which uses strips
of wood along the seams instead of resin putty.
The foam boatbuilding I've seen described requires a building frame to which
a special boatbuilder's foam is attached. It's then covered on the outside
with lots of fibreglass for strength. Then it's femoved from the bulding
frame, turned over, and covered on the inside with more fibreglass. All
that fibreglass makes it heavy.
|
And the cost of the resin in that glass makes it expensive :)
--
I am building a Dudley Dix, Argie 10 for my daughter. Check it out:
http://home.comcast.net/~jonsailr |
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Old Nick
Guest
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| Posted: Wed Jan 05, 2005 8:06 pm Post subject: Re: foam vs luan |
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On Wed, 05 Jan 2005 03:43:20 GMT, Ookie Wonderslug <ookie@my-deja.com>
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email
| Quote: | What is the cheapest foam sheeting that one can buy that will not
melt when you apply polyester resin to it?
|
urethane. see below
| Quote: | What is the best source for
this foam?
|
hardware stores. glass shops
| Quote: | How much does it cost? Would it better than using luan as a
core?
|
No.!!!!!
First, unless you _want_ to build a boat (a desire will not argue
with) look at secondhand stuff, pro built. You will probably not pay
more than building, and should you be one of those fortunate souls
that can sell stuff you have, you will get more for it.
OK. Wood cores vs foam cores.
(1) For a small knockabout, use ply core. It spreads (resists point
loads; rocks, feet, jetties, etc) the load far more than any foam. If
the skin is damaged, it still keeps some shape. Kayaks are built from
ply or strip wood, because the result is more bump resistant/kg than
foam/glass. The wood actually has a structural part to play. For
larger boats it's different. They need stiffness and are less likely
to encounter point loads. Even there, there have been arguments.
(2) I mentioned urethane. Avoid that crap. It crumbles unbder stress.
The ONLY foam worth using in boats is expensive PVC foam. For cost
check out Airex/Klegecell. (Am I showing my age?) For a normal use,
biggish boat, you can't beat it. For a boat that is light and tough,
for rowing and knocking about (less than 20') use ply/glass.
The only _possible_ advantage for foam is that it will not rot. But a
fracture of the glass skin can cause major problems anyway. So....
(3) Boats on a budget are always a problem. Boating above all others
brings out the "weep once" feature. |
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Guest
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| Posted: Wed Jan 05, 2005 11:42 pm Post subject: Re: foam vs luan |
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Foam compatible with resin will cost much much more than plywood.
We sell the foam and the plywood and everything else. We often say that
in small sizes, a foam sandwich boat will cost twice what a stitch and
glue boat cost.
Jacques from bateau.com
Old Nick wrote:
| Quote: | On Wed, 05 Jan 2005 03:43:20 GMT, Ookie Wonderslug
ookie@my-deja.com
vaguely proposed a theory
......and in reply I say!:
remove ns from my header address to reply via email
What is the cheapest foam sheeting that one can buy that will not
melt when you apply polyester resin to it?
urethane. see below
What is the best source for
this foam?
hardware stores. glass shops
How much does it cost? Would it better than using luan as a
core?
No.!!!!!
First, unless you _want_ to build a boat (a desire will not argue
with) look at secondhand stuff, pro built. You will probably not pay
more than building, and should you be one of those fortunate souls
that can sell stuff you have, you will get more for it.
OK. Wood cores vs foam cores.
(1) For a small knockabout, use ply core. It spreads (resists point
loads; rocks, feet, jetties, etc) the load far more than any foam. If
the skin is damaged, it still keeps some shape. Kayaks are built from
ply or strip wood, because the result is more bump resistant/kg than
foam/glass. The wood actually has a structural part to play. For
larger boats it's different. They need stiffness and are less likely
to encounter point loads. Even there, there have been arguments.
(2) I mentioned urethane. Avoid that crap. It crumbles unbder stress.
The ONLY foam worth using in boats is expensive PVC foam. For cost
check out Airex/Klegecell. (Am I showing my age?) For a normal use,
biggish boat, you can't beat it. For a boat that is light and tough,
for rowing and knocking about (less than 20') use ply/glass.
The only _possible_ advantage for foam is that it will not rot. But a
fracture of the glass skin can cause major problems anyway. So....
(3) Boats on a budget are always a problem. Boating above all others
brings out the "weep once" feature. |
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Jim Conlin
Guest
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| Posted: Thu Jan 06, 2005 1:28 am Post subject: Re: foam vs luan |
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Ookie Wonderslug wrote:
| Quote: | What is the cheapest foam sheeting that one can buy that will not
melt when you apply polyester resin to it? What is the best source for
this foam? How much does it cost? Would it better than using luan as a
core?
I need a bigger jon boat. Mine is 40 years old and starting to fall
apart. I am going to build one, but money is a deciding factor in
this. If I had the cash, I would just go to Outdoor World and buy one
of theirs for $500. But since I don't have that kind of green I guess
I can build one. I would like to use foam as a core because it is
light and easy to form. I could see glueing a boat together out of 1/2
or 3/4 inch sheet foam and then glassing it. It just feels like it
would be easier than building a frame and then attaching the luan and
then glassing that. However I have never built a boat. I have rebuilt
a couple, but never built one from scratch.
Any advice? Pointers? Suggestions?
Lauan is generally not water resistant. It'll fall apart very quickly. |
No part of a boat should be made of it.
The foams that have any structural properties and expensive, and the
cheap foams are weak.
The best material for building a small boat inexpensively is exterior
fir AC plywood and stitch & glue construction. A light sheathing of
glass in epoxy will stop the fir from checking. |
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William R. Watt
Guest
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| Posted: Fri Jan 07, 2005 8:54 pm Post subject: Re: foam vs luan |
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please note that we are discussing replacing a jon boat here, a small
boat. foam core gets "light and strong" as the hull volume increases.
for small boats like this jon boat it is heavier than plywood.
laun underlayment is okay for small boats that don't have to last a long
time and preferably can be stored under cover. I have two small boats made
of laun underlayment. The only finish on them is a 2 coats of exterior
grade latex house paint. I go over the finish a couple times a year. Laun
underlayment is 1/5 inch thick. Although the wood is rot resistant it's
only 3 ply and the face ply is thin. It weighs 17 lb per 4x8 sheet
compared to dougals fir at 22 lb. I'd use it for a small lightweight
cartop boat stored under cover when not in use, with some hull curvature
for strength and no long unsupported panels. I use skids on the bottom to
give strength (photos on my website below). There is a better grade of
underlayment called "meranti" that has replaced lauan here in Ottawa the
past 2 years. Personally, for a cheap jon boat which might get some rough
treatement I'd use painted douglas fir plywood and cover or store it out
of the sun so the surface doesn't check. I don't think anyone makes spruce
plywood any more. I have a few scraps of exterior grade spruce but have
not seen any for sale for years. Now they use that chip board and oriented
strand board to sheath houses.
--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned |
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Twilk
Guest
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| Posted: Tue Feb 01, 2005 7:54 pm Post subject: Re: foam vs luan |
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IMO a jon boat is perfect for plywood or aluminum construction and not a
foam core boat
which can be an expensive complicated project that leaves you with an
inferior boat. |
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