Paul Oman wrote:
Courtney Thomas wrote:

Dave W wrote:

They are different formulations. Follow mfgr. ratio data exactly.
This is not a place for experiments!
Dave

Thank you.

I can see I failed to adequately state my concern :-)

Chemically, what is the difference in the resins when using the
different formulations that require different amounts of hardener ?

If only the viscosities are different, how are these different
formulations attained ?

Also, what is the difference in the hardeners, if any ?

Is there a known website that fully delves into this without bias ?

Thank you,
Courtney


----------------
Hi Courtney


There are about three different epoxy resins (bis A, F, and novolac).
Just about everyone uses Bis A....
There are about 60 different curing agents that can be used.

So.... most epoxies are, or can be, a blend of different curing agents.
On top of that there are thinks like nonyl ... that can be added to part
A or B to even out the mix ratios, lower the price, change visc. etc.

The curing agents are a lot more expensive than the resins so
forumulating an epoxy with with a 4 to 1 or so mix ratio (instead of a 1
to 1 or 2 to 1 ratio) saves the formulator $$ (or increases their profits)
paul oman - progressive epoxy polymers, Inc.
---------------------------------------------------------------

Thank you Paul.

What's the difference between bis, A, F and novolac ?

What do the 'curing agents' actually do ? Catalyze the polymerization ?

Is the reason that everyone doesn't use the same 'hardener', because
different ones lend a different character to the curing process,
otherwise, the same end product... results ?

So, is the bottom line that....if you can find a 1:1 or 2:1 mix that
will satisfy your needs, that's the best way to go and the more exotic
formulations are also more circumscribed in terms of usage hence more
likely to be inappropriately applied, such as low temp applications,
etc., that ultimately don't properly cure due to a flawed application
process, hence fail ?

Would this be just one more example of vendors bamboozling customers
with attempts at masking a generic product with proprietary
'technology', witness the auto manufacturers and their glomming onto
electronics, or do some actually have worthwhile differences and related
costs and PERFORMANCE, that justify their claims and charges ?

Any online references that address this ?

Appreciatively,

Courtney

OPINION!

One size does not fit all. One design is not satisfying to all people.

I've gotten used to System Three which uses a 2:1 mix. West System (Gougeon
Brothers) uses a 5:1 mix. Both are vendors who have satisfied customers for
decades. Neither is bamboozling the customers. They use their own products
and document the results. IMHO, the lower the ratio, the less you
compromise the final product, but "acceptable" is a compromise and there is
a range of "good enough."

The stuff we used on the F-16, F-22, and A-12 was quite different from what
I use in the barn for my boat, and the difference didn't happen in the
user's shop. Are you prepared to use an oven and follow a careful post-cure
time/temperature schedule to achieve the results you want? Caution, it may
take several tries to get it right. On A-12, several LARGE center wing
assemblies were unusable because the thermostat wasn't accurate.

The stuff from Dow is not suitable for use in boat building. We typically
use a "room temperature" cure and want a bond which is compatible with a
wooden structure. Check out http://epoxy.dow.com/products/p-liquid.htm
Building an aircraft structure, repairing a china cup, patching an engine
block ... all require different additives.

Boat builders are not a stupid, uneducated group. Don't think you are the
first to wonder about "contributed value."

Roger (BSE-Physics, Univ. of Illinois)

http://home.earthlink.net/~derbyrm

"Courtney Thomas" wrote in message
ink.net...
Paul Oman wrote:
snip
So, is the bottom line that....if you can find a 1:1 or 2:1 mix that will
satisfy your needs, that's the best way to go and the more exotic
formulations are also more circumscribed in terms of usage hence more
likely to be inappropriately applied, such as low temp applications, etc.,
that ultimately don't properly cure due to a flawed application process,
hence fail ?

Would this be just one more example of vendors bamboozling customers with
attempts at masking a generic product with proprietary 'technology',
witness the auto manufacturers and their glomming onto electronics, or do
some actually have worthwhile differences and related costs and
PERFORMANCE, that justify their claims and charges ?

Roger Derby wrote:

The stuff from Dow is not suitable for use in boat building.

Not quite.

There are only 3-4 basic resin suppliers in the world.

Dow, Ciba-Geigy and Shell come to mind.

There may be another one or two.

Each of the major formulators works with typically only one resin supplier.

That's enough.

I know my suppliers are a Dow house.

They supply material to build more than one boat builder including me.

Lew

With the resources available in your VERY large home city and your skills at
purchasing, I'm not surprised. If I'm not mistaken, you're buying the resin
in 55 gallon drums.

Where do you get your hardeners and who supplied the formulae?

Roger

http://home.earthlink.net/~derbyrm

"Lew Hodgett" wrote in message
k.net...
Roger Derby wrote:
The stuff from Dow is not suitable for use in boat building.

Not quite.
There are only 3-4 basic resin suppliers in the world.
Dow, Ciba-Geigy and Shell come to mind.
There may be another one or two.
Each of the major formulators works with typically only one resin
supplier.
That's enough.
I know my suppliers are a Dow house.
They supply material to build more than one boat builder including me.

Lew

Roger Derby wrote:


Where do you get your hardeners and who supplied the formulae?


I use Diversified Materials Corp in San Diego.

The formulator supplies the chemistry.

Lew

On Thu, 10 Nov 2005 04:27:41 +0000, Lew Hodgett wrote:

Roger Derby wrote:

The stuff from Dow is not suitable for use in boat building.

Not quite.

There are only 3-4 basic resin suppliers in the world.

Dow, Ciba-Geigy and Shell come to mind.

[snip]

I think Shell sold their epoxy works to Resolution Performance Products.
There is a lot of information about various formulations at
www.resins.com, the Resolution website.

--Mac

Hey, nobody says you can't reinvent the wheel. What irritates me is that
the people who have spent years developing the proper formulations and
techniques are expected to work for free. Sort of like saying "Hey.
There's nothing in this book except the letters I learned in kindergarten.
Why should I pay the author?" If enough people adopt that attitude, no one
will bother publishing anything.

Maybe the rest of you find boatbuilding so easy that you can devote your
energies to doing the tasks that come bundled with a purchase from System
Three or West Systems; product support, trouble shooting, documentation,
storage, shipping and handling. I'd rather buy small quantities of
ready-to-use stuff in order to spread the cost over time and profit from
their mistakes.

A recurring theme in the criticism of technical reports is that they never
discuss the blind alleys, fires, explosions and other events that ran the
project cost up to two or three times what was expected. To read the report
or listen to the presentation one would think that it was just a matter of
doing X, then Y, and then Z; of course.

At GD it was common to see a gallon can of epoxy blazing away on the
apron -- thermal runaway. Another recurring problem was quality control --
how do you know that the "wet out" was complete when the exterior looks
fine. Ultrasound scanning of every square inch is messy and expensive. (To
couple the transducer to the skin being examined, one uses a gel.) It also
requires operator skills that take time to develop. ...

Ah, well. Sorry. Rant over.
Roger

http://home.earthlink.net/~derbyrm

"Mac" wrote in message
news
On Thu, 10 Nov 2005 04:27:41 +0000, Lew Hodgett wrote:

Roger Derby wrote:

The stuff from Dow is not suitable for use in boat building.

Not quite.

There are only 3-4 basic resin suppliers in the world.

Dow, Ciba-Geigy and Shell come to mind.

[snip]

I think Shell sold their epoxy works to Resolution Performance Products.
There is a lot of information about various formulations at
www.resins.com, the Resolution website.

--Mac

Courtney Thomas wrote:

Paul Oman wrote:

Courtney Thomas wrote:

Dave W wrote:

They are different formulations. Follow mfgr. ratio data exactly.
This is not a place for experiments!
Dave

Thank you.

I can see I failed to adequately state my concern :-)

Chemically, what is the difference in the resins when using the
different formulations that require different amounts of hardener ?

If only the viscosities are different, how are these different
formulations attained ?

Also, what is the difference in the hardeners, if any ?

Is there a known website that fully delves into this without bias ?

Thank you,
Courtney



----------------
Hi Courtney


There are about three different epoxy resins (bis A, F, and novolac).
Just about everyone uses Bis A....
There are about 60 different curing agents that can be used.

So.... most epoxies are, or can be, a blend of different curing
agents. On top of that there are thinks like nonyl ... that can be
added to part A or B to even out the mix ratios, lower the price,
change visc. etc.

The curing agents are a lot more expensive than the resins so
forumulating an epoxy with with a 4 to 1 or so mix ratio (instead of
a 1 to 1 or 2 to 1 ratio) saves the formulator $$ (or increases their
profits)
paul oman - progressive epoxy polymers, Inc.
---------------------------------------------------------------

Thank you Paul.

What's the difference between bis, A, F and novolac ?


********* Bis A resins are the most common. Bis F and
especially
novolac provide much better chemical (an a bit more
chemical resistance.


What do the 'curing agents' actually do ? Catalyze the polymerization ?


******** they are the other half the the equation needed
for the
reaction to happen the forms the complete epoxy


Is the reason that everyone doesn't use the same 'hardener', because
different ones lend a different character to the curing process,
otherwise, the same end product... results ?


******* yes pretty much the same end result, but yes
different ones do
have dif properties (cure rates, times, blushing
properties, etc.
Suspect $$$ is the controlling factor for some epoxy
manufacturers.


So, is the bottom line that....if you can find a 1:1 or 2:1 mix that
will satisfy your needs, that's the best way to go and the more exotic
formulations are also more circumscribed in terms of usage hence more
likely to be inappropriately applied, such as low temp applications,
etc., that ultimately don't properly cure due to a flawed application
process, hence fail ?

******* in a marine setting they pretty much all will work.
Boatbuilding, marine applications, etc. are not very
demanding for
epoxies, hence there are lots of them out their (we think
ours in one of
the best!)


Would this be just one more example of vendors bamboozling customers
with attempts at masking a generic product with proprietary
'technology', witness the auto manufacturers and their glomming onto
electronics, or do some actually have worthwhile differences and
related costs and PERFORMANCE, that justify their claims and charges ?


****** lots of ways to make an apple pie. It's all apple
pie but we
all have favorites (and some like it with raisins). Yes,
most if it is
very overpriced.


Any online references that address this ?


****** yes, but afraid they are all written and posted by
me! paul
oman - progressive epoxy polymers


Appreciatively,

Courtney



--


"Living on Earth is expensive, but it does include
a free trip around the Sun every year."


============================================
PAUL OMAN Progressive Epoxy Polymers, Inc.
Frog Pond Hollow - 48 Wildwood Drive
Pittsfield NH 03263
10:30-3:30 Monday-Thur EST 603-435-7199
VISA/MC/Discover/Paypal

http://www.epoxyproducts.com
============================================