"Ed Edelenbos" wrote
Hmmm.... I guess it must be different for working people. I've known
several boat yard operators and pile drivers who use this method (for
their own boats). Actually, the most common way is to use regular epoxy
resin and thin it with acetone to the right consistency. I know of a
couple rib repairs that are about 25 years old and still in place.


It depends very much on what the original structure was like (ie massive
workboat construction or slender scantling yacht type); and what stress
it's put under.

From an engineering standpoint, Glenn's comments are 100% accurate.
Epoxy saturation restores much of the strength in compression of the
original wood, some of the shear strangth, and very littl of the
strength in tension (which is wood's strongest point).



Glenn Ashmore wrote:
Epoxy stabilizes the wood and prevents further rotting

Note- in the original part... it does little or nothing to stop leaks
and prevent further rot around the margins of the saturated area!

.... but it has much lower
tensile strength than the wood and is considerably less resiliant. Unless
the part is reinforced with carefully aligned glass fiber it will not be up
to the task.


This correspnds exactly with my experience. I've seen mooring cleats
pull up out of rot-doctored decks which were hard as a rock from the epoxy.

When fresh out of the military and needing something to do, a friend and
I "restored" (or butchered, depending on who you talk to) an old classic
racing yacht. The planking was sound but the structure and deck was
spongy. We built a 6 point cradle with shaped frames, epoxy saturated
much of the interior structure, and laid up an internal truss mimicking
the original ribs & floors with some diagonals added. The boat had no
stiffness or strength in the hull until we added fiberglass cloth along
the truss members. After that, it was very strong & we raced the heck
out of it.

A few classic boat purists were upset at what we'd done, two or three
even threatened us. But the boat would have become a mulch pile and we
did this work in about 3 months instead of seven years to rebuild it the
"right" way.

YMMV

Fresh Breezes- Doug King

"DSK" wrote in message
...
"Ed Edelenbos" wrote
Hmmm.... I guess it must be different for working people. I've known
several boat yard operators and pile drivers who use this method (for
their own boats). Actually, the most common way is to use regular epoxy
resin and thin it with acetone to the right consistency. I know of a
couple rib repairs that are about 25 years old and still in place.


It depends very much on what the original structure was like (ie massive
workboat construction or slender scantling yacht type); and what stress
it's put under.


This is exactly what I said... it depends on the task. For the statement
"Unless the part is reinforced with carefully aligned glass fiber it will
not be up to the task." to be made, it assumes that either it is unsuitable
for ANY task, or that ALL tasks are the same. Neither of these assumptions
are correct.

I'll stand by what I said... it is a rediculous assertion.

Ed

And I stand by what I said. I doubt that there is anyone on this newsgroup
working with timbers and anyone relying on soaking a rotten frame or
stringer with Rot Doctor is asking for trouble. The only way they will get
the same strength is to replace it, sister it or glass it after stabilizing
it.

A sound piece of clear fir has a tensile strength of about 12,600 PSI.
CPES, the most commercially available epoxy wood stabilizer, has a tensile
strength of around 4,500 PSI and, for fairly obvious reasons, there is no
ANSI standard tensile strength of rotten wood. Even Rot Doctor recommends
glass reinforcement for members subject to tension or shear.

Rot also occurs primarily at the joint with another member. On an interior
member like a frame or stringer that is usually the outboard side which is
normally subject to the greatest tension. Unless the tensile strength is
restored in one way or another the treated member will be a weak point and
risks becoming the starting point for failure.


Please pardon a short rant:
I have been participating in this news group for 7 years and in that time
have seen people espousing everything from antifreeze to aspirin to cure rot
and curtain liner to wheat flour to save a few pennies on GRP lay-ups. It
irritates me no end to hear people insisting on short cuts and off the wall
ways to save a few bucks and screw up a job.

I would guess that about half the participants in this news group are first
time boat builders/restorers looking for advice. We have succeeded in
chasing off all the pros so it is up to those of us with a little experience
to guide them. That is a responsibility that should not be taken lightly.
End rant:

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Ed Edelenbos" wrote in message
...
"DSK" wrote in message
...
"Ed Edelenbos" wrote
Hmmm.... I guess it must be different for working people. I've known
several boat yard operators and pile drivers who use this method (for
their own boats). Actually, the most common way is to use regular epoxy
resin and thin it with acetone to the right consistency. I know of a
couple rib repairs that are about 25 years old and still in place.


It depends very much on what the original structure was like (ie massive
workboat construction or slender scantling yacht type); and what stress
it's put under.


This is exactly what I said... it depends on the task. For the statement
"Unless the part is reinforced with carefully aligned glass fiber it will
not be up to the task." to be made, it assumes that either it is
unsuitable for ANY task, or that ALL tasks are the same. Neither of these
assumptions are correct.

I'll stand by what I said... it is a rediculous assertion.

Ed

"Glenn Ashmore" wrote in message
news:GGB2f.306$Kp4.137@lakeread08...
. We have succeeded in chasing off all the pros End rant:

With pointless little self serving rants I assume.

Ed

"Ed Edelenbos" ) writes:
"Glenn Ashmore" wrote in message
news:GGB2f.306$Kp4.137@lakeread08...
. We have succeeded in chasing off all the pros End rant:

With pointless little self serving rants I assume.

Moulded fibreglass has made of boatbuilding a very competiive low-margin
business. Boatyards are not even located on high priced waterfront
property anymore, but in municipal industrial parks. The pros who posted
here may very well have gone out of business or got tired of people
questioning the obvious self-interest of some in posting here. Others have
their own websites with forums where they control the content.
Contrary to GA's rant not all of the people who make a living off
boatbuilding have desterted the newsgroup. There is not the voume of mass
produced wooden boats to support a whole wooden boatbuilding industry any
more. It's very low volume. The economics of moulded boats supports mass
production, not custom work. In fact the economics of mass production has
also eliminated a lot of custom building in such areas as automobiles and
houses. You can still save money building your own house or boat, or spend
a lot of money on having one custom built if you can afford it. But it's
not like it used to be or like nostalgic sentimentalists like to believe
it still is.

--
------------------------------------------------------------------------------
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

What Glenn said.

There are good ways to do a repair and there are half-assed ways.
For structural repairs to boats where people will be in water too deep to
walk home when it sinks, methods like infusion with solvented epoxy are
irresponsible.

BS

--
When replying via email, replace spam with speak in the address.
"Jim Conlin" wrote in message
...
What Glenn said.

There are good ways to do a repair and there are half-assed ways.
For structural repairs to boats where people will be in water too deep to
walk home when it sinks, methods like infusion with solvented epoxy are
irresponsible.

On Tue, 11 Oct 2005 00:53:58 -0400, "Ed Edelenbos"
wrote:

BS

Pretty much looks like you are a minority of one 'round here, my
friend.

Why don't you try an experiment on rotten wood and restore it to its
original strength.....or any sigificant strength.That'll be a stronger
argument than name calling.

After that you could raise a few of my dead relatives. I've got some
old scores to settle.

"P.C. Ford" wrote in message
...
On Tue, 11 Oct 2005 00:53:58 -0400, "Ed Edelenbos"
wrote:

BS

Pretty much looks like you are a minority of one 'round here, my
friend.

Why don't you try an experiment on rotten wood and restore it to its
original strength.....or any sigificant strength.That'll be a stronger
argument than name calling.


Being in the minority doesn't make one wong. Especially with the
statistically small sampling of boat repairers here. Get out in the real
world, friend. There is life beyond the computer screen. And, I have yet
to call anyone a name brother.

After that you could raise a few of my dead relatives. I've got some
old scores to settle.

I guess next you'll tell me they all died on boats repaired with epoxy
saturated wood.

Ed

"Glenn Ashmore" ) writes:

Please pardon a short rant:
I have been participating in this news group for 7 years and in that time
have seen people espousing everything from antifreeze to aspirin to cure rot
and curtain liner to wheat flour to save a few pennies on GRP lay-ups. It
irritates me no end to hear people insisting on short cuts and off the wall
ways to save a few bucks and screw up a job.

Could you please elaborate on the use of asprin for boat repair, assuming
it is being applied to the boat and not the boatbuilder? That's a new one
on me.

By curtain liner do you mean the polyester fabric? I've tried the
ployester drapery moulding, the stuff they use to stiffen the top where
they put in the hooks. It's okay for some places but not as flexible to
apply as fibreglass tape. There is a mix of the drapery tape and
fibreglass cloth imbedded in the polyester resin on my 12 foot, 25 pound
plywood Delta boat. Neither fibre has given any trouble so far.

I've never actually built a carboard boat but if you could somehow get
hold of waterproof cardboard I bet it would make a great boatbuilding
material for lightweight canoes and kayaks.

By way of a reminder, we are not all building 50 foot offshore cruisers
costing more than the average family residence to pass on to our
granchildren as artifacts of consicuous consumption. Or making our living
off people who do.


--
------------------------------------------------------------------------------
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