In article ,
"Allan" wrote:

Hi. I'll probably get some thoughts on this. I built a 20' Osprey Triple
kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident Power
Cat ( johnsboatstuff.com ). He's recommending epoxy for structural work and
polyester (either orthothalic or the other one, I can't remember right now,
would have to look at my plans) for glassing up. Anyway it's the "better"
polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

experience varies. on some surfaces polyester is fine. some builders have
been using is successfully for decades. but as there is no experimental
data a lot of builders pay extra and use epoxy. if your designer
recommends polyester you might want to contact him or her to find out what
feedback he is getting from builders.

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

Allan,

Thirty five years ago, when epoxy was hundreds of dollars a gallon, we
used poly for glassing, never as an adhesive (it was not as strong as a
good glue). The general consensus of the experts was that It should
only be used for glassing on a virgin, stable, substrate which was
mostly plywood back then. NEVER on planking, strips, etc or previously
painted wood, because the bonding strength and sheer strength would not
hold up to the forces which resulted in the expansion of these
substrates or the poor penetration of the previously painted surface.

The first coat of poly was thinned with styrene (the base solvent of
polyester) 30% as I recall, immediately followed by a straight coat that
the glass was laid into. The rest of the buildup was as with epoxy
except you had to work your ass off if the job was of any size. This
method worked ok and some of it lasted at least several decades. The
ones that failed were usually the ones that violated the rules above or
were boats that were grossly mistreated. For instance, acetone was
substituted for styrene which reduced the mechanicals of the poly by
about 20% to 30% as I recall.

About the same time I was introduced to epoxy in the lab at GE (they
could afford it). For the next twenty or so years I waited for the
price of epoxy to come down to my recreational budget level. That was
about 15 years ago and I have not used poly since. As far as I am
concerned, the only justification for poly is in high volume production
molded parts (unfortunately like boat hulls). But even there you will
see the highest quality products using epoxy.

Bottom line. With epoxy at $40 to $50 a gallon, I wouldn't use poly if
it were FREE!

My opinion, worth what you paid for it.

Regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Michael O'Dell wrote:

In article ,
"Allan" wrote:

Hi. I'll probably get some thoughts on this. I built a 20' Osprey Triple
kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident Power
Cat ( johnsboatstuff.com ). He's recommending epoxy for structural work and
polyester (either orthothalic or the other one, I can't remember right now,
would have to look at my plans) for glassing up. Anyway it's the "better"
polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

I guess that's why all my 30 year old poly boats just collapsed
into piles of hairy dust in my backyard, eh? Zero strength, eh?

How do you calculate the cost benefit from this supposed longer
life for epoxy, given that the life span is still generally
indeterminate for both types under reasonable stresses? I have
heard of very few poly boats disintegrating in any remarkably
shorter time than epoxy, even in contests involving rocks and
stuff.

Such extremeist statements suggest you must be a berserker stock
market manipulator with interests and positions in the epoxy
chemicals market bordering so extremely on the insane as to
suggest you sell epoxy mainly to be able to continue to dispose
of toxic chemicals added in small amounts to the resins, just
like some shampoo vendors I suspected of doing just that until
your arguement was so strongly stated and foolishly revealed ;-)

Now, as far as skin irritation and developed allergies and
consequent lifetime sensitivities and costs associated with
respirators, deformed babies, etc, I would favour poly quite
strongly for a hobby builder, especially a relatively
inexperienced one, especially for a first build. Commercially,
the evidence is overwhelming. I cannot imagine anyone smart
enough to be able to afford the costs of epoxy being insensitive
to those cost benefit analyses so evidently performed and adhered
to by professional builders.

You just try to get an informed professional to build in epoxy
and then count the costs.

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

As one who has need for some poly glassing I have often thought there should
be another news group for "ordinary" people.
My whole boat is poly so why do some alterations in epoxy?
BruceM


"Terry Spragg" wrote in message
...


Michael O'Dell wrote:

In article ,
"Allan" wrote:

Hi. I'll probably get some thoughts on this. I built a 20' Osprey
Triple
kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident
Power
Cat ( johnsboatstuff.com ). He's recommending epoxy for structural
work and
polyester (either orthothalic or the other one, I can't remember right
now,
would have to look at my plans) for glassing up. Anyway it's the
"better"
polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

I guess that's why all my 30 year old poly boats just collapsed
into piles of hairy dust in my backyard, eh? Zero strength, eh?

How do you calculate the cost benefit from this supposed longer
life for epoxy, given that the life span is still generally
indeterminate for both types under reasonable stresses? I have
heard of very few poly boats disintegrating in any remarkably
shorter time than epoxy, even in contests involving rocks and
stuff.

Such extremeist statements suggest you must be a berserker stock
market manipulator with interests and positions in the epoxy
chemicals market bordering so extremely on the insane as to
suggest you sell epoxy mainly to be able to continue to dispose
of toxic chemicals added in small amounts to the resins, just
like some shampoo vendors I suspected of doing just that until
your arguement was so strongly stated and foolishly revealed ;-)

Now, as far as skin irritation and developed allergies and
consequent lifetime sensitivities and costs associated with
respirators, deformed babies, etc, I would favour poly quite
strongly for a hobby builder, especially a relatively
inexperienced one, especially for a first build. Commercially,
the evidence is overwhelming. I cannot imagine anyone smart
enough to be able to afford the costs of epoxy being insensitive
to those cost benefit analyses so evidently performed and adhered
to by professional builders.

You just try to get an informed professional to build in epoxy
and then count the costs.

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

BruceM wrote:

As one who has need for some poly glassing I have often thought there should
be another news group for "ordinary" people.
My whole boat is poly so why do some alterations in epoxy?

And be chained to epoxy therever after?

When I moved the head intake aboard my "The Penny Louise" HR28
sloop to make room for monkey feet under the new saloon booth
table decoratif, I used a one piece 3/8" solid plug of poly glass
tapered to fit the ground out hole, pressed between thin plywoods
lined with waxed paper. It never even needed sanding after it
cured. After vandals burned my boat, while the insurance
swindler was viewing the wreckage, I bashed in the speedo sensor
to allow the water to drain. We came back after a few beers so he
could check out the remains of the hull interior (?) I paid for
the lunch. It seems to me now that I could have tried to bash in
the 3 year old patch, but I didn't think of it then.

After this long, I think that the cradle, hull, engine, gas fuel
tank, boom, ballast, shaft and rudder were useable, (I had just
re-glassed the shaft log using epoxy), I just didn't have the
heart to rebuild. After a year of arguing with Parizeau et bureau
legal d'assurance, I accepted 14,500 and carriage for a boat that
was insured and not replaceable for 18,500, it's purchase price.

I maintain perfect faith that it would have been one hell of a
job to bash in that plug.

Wanna buy a 2 cylinder, 2 cycle gas 20 hp Lloyds Mariner (German)
inboard with electric start, reverser, shaft and prop? It did
well on the 'penile ooies', as we called her.

Terry K

BruceM

"Terry Spragg" wrote in message
...


Michael O'Dell wrote:

In article ,
"Allan" wrote:

Hi. I'll probably get some thoughts on this. I built a 20' Osprey
Triple
kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident
Power
Cat ( johnsboatstuff.com ). He's recommending epoxy for structural
work and
polyester (either orthothalic or the other one, I can't remember right
now,
would have to look at my plans) for glassing up. Anyway it's the
"better"
polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

I guess that's why all my 30 year old poly boats just collapsed
into piles of hairy dust in my backyard, eh? Zero strength, eh?

How do you calculate the cost benefit from this supposed longer
life for epoxy, given that the life span is still generally
indeterminate for both types under reasonable stresses? I have
heard of very few poly boats disintegrating in any remarkably
shorter time than epoxy, even in contests involving rocks and
stuff.

Such extremeist statements suggest you must be a berserker stock
market manipulator with interests and positions in the epoxy
chemicals market bordering so extremely on the insane as to
suggest you sell epoxy mainly to be able to continue to dispose
of toxic chemicals added in small amounts to the resins, just
like some shampoo vendors I suspected of doing just that until
your arguement was so strongly stated and foolishly revealed ;-)

Now, as far as skin irritation and developed allergies and
consequent lifetime sensitivities and costs associated with
respirators, deformed babies, etc, I would favour poly quite
strongly for a hobby builder, especially a relatively
inexperienced one, especially for a first build. Commercially,
the evidence is overwhelming. I cannot imagine anyone smart
enough to be able to afford the costs of epoxy being insensitive
to those cost benefit analyses so evidently performed and adhered
to by professional builders.

You just try to get an informed professional to build in epoxy
and then count the costs.

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®


--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

BruceM wrote:

As one who has need for some poly glassing I have often thought there should
be another news group for "ordinary" people.
My whole boat is poly so why do some alterations in epoxy?
BruceM

So they will stick together?

Just a thought.

For more than twenty years, we did almost all the fiberglass work that
we did with one or the other kinds of polyester and then a little bit of
vinylester. These were the industries lead materials. Epoxy was
reserved for high temperature and polystrene foam assemblies largely
because of cost.

In that time I did experience several dozen mix failures (where the pot
kicks too soon or does not harden correctly) and all mixing was done on
a balance - no by guess and by gosh.

Also, while working with polyester, we (my father and I ran the boat
shop) had numerous bond failures in the work we had done. We also
repaired a significant number of bond failures in other people's work -
four that I remember were factory jobs. Two of those factory jobs were
conversions to wheel steer that lost cable turning point anchors.

Shortly before my father died in 1980, we started to change to epoxy.
This was mostly driven by the little pumps that could be used measure
the material for mixing. We soon discovered that, except for large
builds where material was a big part of the overall cost, the epoxy jobs
were at least no more expensive because of the lack of lost material.

I have one mix failure (caused by a helper that did not understand the
mix ratio was 1 pump stroke to 1 pump stroke), and have never been able
to identify a bond failure in my own work.

We now do all or clean up with white vinegar and reserve acetone and MEK
for work outside.

Matt Colie www.southpointechandler.com

BruceM wrote:

As one who has need for some poly glassing I have often thought there should
be another news group for "ordinary" people.
My whole boat is poly so why do some alterations in epoxy?
BruceM


"Terry Spragg" wrote in message
...


Michael O'Dell wrote:

In article ,
"Allan" wrote:


Hi. I'll probably get some thoughts on this. I built a 20' Osprey

Triple

kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident

Power

Cat ( johnsboatstuff.com ). He's recommending epoxy for structural

work and

polyester (either orthothalic or the other one, I can't remember right

now,

would have to look at my plans) for glassing up. Anyway it's the

"better"

polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

I guess that's why all my 30 year old poly boats just collapsed
into piles of hairy dust in my backyard, eh? Zero strength, eh?

How do you calculate the cost benefit from this supposed longer
life for epoxy, given that the life span is still generally
indeterminate for both types under reasonable stresses? I have
heard of very few poly boats disintegrating in any remarkably
shorter time than epoxy, even in contests involving rocks and
stuff.

Such extremeist statements suggest you must be a berserker stock
market manipulator with interests and positions in the epoxy
chemicals market bordering so extremely on the insane as to
suggest you sell epoxy mainly to be able to continue to dispose
of toxic chemicals added in small amounts to the resins, just
like some shampoo vendors I suspected of doing just that until
your arguement was so strongly stated and foolishly revealed ;-)

Now, as far as skin irritation and developed allergies and
consequent lifetime sensitivities and costs associated with
respirators, deformed babies, etc, I would favour poly quite
strongly for a hobby builder, especially a relatively
inexperienced one, especially for a first build. Commercially,
the evidence is overwhelming. I cannot imagine anyone smart
enough to be able to afford the costs of epoxy being insensitive
to those cost benefit analyses so evidently performed and adhered
to by professional builders.

You just try to get an informed professional to build in epoxy
and then count the costs.

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

"BruceM" wrote in message ...
As one who has need for some poly glassing I have often thought there should
be another news group for "ordinary" people.
My whole boat is poly so why do some alterations in epoxy?
BruceM

No reason at all! But I still say for new construction, epoxy is just
easier to use, guess I am just lazy and want the boat to come out
right the first time without the unaviodable waste of material,
sanding off early cured material, scraping off material that did not
"like" the ambient temp, humidity, or mixing ratio you have chosen to
address the same.
I did build several boats in poly in the beginning, when I finally
broke down and used epoxy, it was a life altering experience, kinda
like going from a tricycle to a Porche...


"Terry Spragg" wrote in message
...


Michael O'Dell wrote:

In article ,
"Allan" wrote:

Hi. I'll probably get some thoughts on this. I built a 20' Osprey
Triple
kayak using epoxy resin. Nice boat. Now I'm building an 18' Trident
Power
Cat ( johnsboatstuff.com ). He's recommending epoxy for structural
work and
polyester (either orthothalic or the other one, I can't remember right
now,
would have to look at my plans) for glassing up. Anyway it's the
"better"
polyester. I like the price of the polyester, but..................

Anybody have any thoughts on why I should go all epoxy or use the
epoxy/polyester combo??? Thanks for any comments, thoughts.

Amateur 2nd boat builder in the Great White Frozen North,

Allan



build in epoxy - period.

polyester has no secondary bond strength and not
a lot of primary bond strength. epoxy is not
that much more expensive and could well save
your boat. epoxy actually sticks to the glass
where polyester does not; it merely hardens
*around* the glass fibers. that's why a polyester
laminate peels apart along the surface of the
reinforcement when it goes into failure.

-mo

I guess that's why all my 30 year old poly boats just collapsed
into piles of hairy dust in my backyard, eh? Zero strength, eh?

How do you calculate the cost benefit from this supposed longer
life for epoxy, given that the life span is still generally
indeterminate for both types under reasonable stresses? I have
heard of very few poly boats disintegrating in any remarkably
shorter time than epoxy, even in contests involving rocks and
stuff.

Such extremeist statements suggest you must be a berserker stock
market manipulator with interests and positions in the epoxy
chemicals market bordering so extremely on the insane as to
suggest you sell epoxy mainly to be able to continue to dispose
of toxic chemicals added in small amounts to the resins, just
like some shampoo vendors I suspected of doing just that until
your arguement was so strongly stated and foolishly revealed ;-)

Now, as far as skin irritation and developed allergies and
consequent lifetime sensitivities and costs associated with
respirators, deformed babies, etc, I would favour poly quite
strongly for a hobby builder, especially a relatively
inexperienced one, especially for a first build. Commercially,
the evidence is overwhelming. I cannot imagine anyone smart
enough to be able to afford the costs of epoxy being insensitive
to those cost benefit analyses so evidently performed and adhered
to by professional builders.

You just try to get an informed professional to build in epoxy
and then count the costs.

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

Bruce,

The "ordinary" people are the ones that can best justify epoxy because
the quantity they typically us is small compared to the production user.

To answer your question about why to use epoxy instead of poly is, that
it makes a better repair.

Regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.