Epoxy is really crap for homebuilding

good points, but I find the odor of vinyl ester no where near as bad
as that Aeropoxy I've been using, with it's amonia based hardener. Man
that stuff is nasty! The styene in the vinyl ester and poly ester has
a sort of sweet smell to it I find not that objectionable. Epoxy does
seem to be more of a universal bonding agent. It definitely sticks to
more substances than vinyl ester does. And it's strength is higher,
but the thing is, it's higher than it needs to be,. I remember when I
first learned about composites, and the rule was the strength is in
the fiber, not the resin. So once you get a resin that will cure hard,
it's done it's job, and the fibers are the strength, whether it be
glass cloth, kevlar, ect... Another annoyance with epoxy is it takes
forever to cure. What a pain to deal with that. The peeling that
vinyl ester does as it ages is probably due to it being outside in the
weather and water in a marine environment. A plane made from it,
protected with paint and in a hangar, would probably never encounter
those issues. So it's ideal for that environment. Plus it was
developed to make underground fuel storage tanks by Dow Chemical. So
it's use as a fuel tank should never be a problem. I've seen Lancair
builders having to coat the inside of their fuel tanks with some type
of reddish rubbery looking stuff. So I guess epoxy isn't go great for
fuel tanks. Another reason to stay away from the toxic stuff in
airplanes.

On Tue, 20 May 2008 09:19:25 -0700 (PDT), Reggie
wrote:



There are some reasons, this URL supplies some of them.
Especially note the repair risks and the liquid styrene risks


http://www.redrockstore.com/resin.htm


A short reprint of the major points follows, but a review of the total
article suggested


Epoxy resin is known in the marine industry for its incredible
toughness and bonding strength.
Quality epoxy resins stick to other materials with 2,000-p.s.i. vs.
only 500-p.s.i. for
vinylester resins and even less for polyesters.
In areas that must be able to flex and strain WITH the fibers
without micro-fracturing,
epoxy resins offer much greater capability.
Cured epoxy tends to be very resistant to moisture absorption.
Epoxy resin will bond dissimilar or already-cured materials which
makes repair work that is
very reliable and strong.
Epoxy actually bonds to all sorts of fibers very well and also offers
excellent results
in repair-ability when it is used to bond two different materials
together.
Initally, epoxy resin is much more difficult to work with and
requires additional skill
by the technicians who handle it.



Vinylester resins are stronger than polyester resins and cheaper than
epoxy resins.
Vinylester resins utilize a polyester resin type of cross-linking
molecules in the
bonding process.
Vinylester is a hybrid form of polyester resin which has been
toughened with
epoxy molecules within the main moleculer structure.
Vinyester resins offer better resistance to moisture absorption than
polyester resins
but it's downside is in the use of liquid styrene to thin it out (not
good to breath that stuff)
and its sensitivity to atmospheric moisture and temperature.
Sometimes it won't cure if the atmospheric conditions are not right.
It also has difficulty in bonding dissimilar and already-cured
materials.
It is not unusual for repair patches on vinylester resin canoes to
delaminate or peel off.
As vinylester resin ages, it becomes a different resin (due to it's
continual curing as it ages)
so new vinylester resin sometimes resists bonding to your older
canoe,
or will bond and then later peel off at a bad time.
It is also known that vinylester resins bond very well to fiberglass,
but offer a poor bond to kevlar and carbon fibers due to the nature of
those two more exotic fibers.
Due to the touchy nature of vinylester resin, careful surface
preparation is necessary if reasonable adhesion is desired for any
repair work.

Can't figure it out!!!?? you don't think the odor of amonia is stinky?
I hate to say it, but breathing that epoxy or some other substances
has burned out your olfactory nerves if you don't find Aeropoxy
objectionable. Although, I have used epoxies that smell like the stuff
in those 5 minute tubes. It;'s not that bad. And I just ordered a
different brand, hoping it will not have that amonia odor to it. And
my Aeropoxy has sat around for a while, and the hardner has turned a
deep red color, so all my layups are now deep red. I've read the
manufactures info on that, and they say that's a normal aging effect
of the hardner and dosen't affect the strength. But I wonder if it
make the smell worse.. hmm..

On Tue, 20 May 2008 13:34:58 -0700 (PDT), BobR
wrote:


I can't quite figure out what the heck you are talking about. I have
worked with epoxy for the last 10 years including Aeropoxy, E-Z Poxy,
West and Hysol. I can not understand you comment about the "stinky"
part at all. I will totally agree with you that Vinyl Ester stinks to
the high heavens but have never experienced any such problem with
epoxy formulations. I can't even stand to work with completed parts
made using the Vinyl Ester but not so with epoxy parts.

I also can't agree with the Toxic comment regarding epoxy since it is
much less toxic than either Vinyl Ester or Polyester Resins.

Guess this is just another case of beauty being in the eye of the
beholder. I rather enjoy working with composites and prefer them to
working with metals.

On Tue, 20 May 2008 14:39:35 -0700 (PDT), bizguy
wrote:



For me health is a major issue. I am extremely allergic to it.

I would enjoy working on a plane, but now most all plans specify its
use.


Epoxy is the one with the allergy problem. You could probably work
with vinyl ester, and all the Glasairs are made from it, and some
other designs. They say they've not had one instance of anyone being
allergic to vinyl ester resin. Although I know of one builder who
claims to have become sensitized to it. But I suspect it's a lie to
cover up their getting burned out on the project very early and
wanting a good excuse as to why they got rid of it.

On Tue, 20 May 2008 16:42:04 -0500, Gig 601Xl Builder
wrote:

bizguy wrote:

For me health is a major issue. I am extremely allergic to it.

I would enjoy working on a plane, but now most all plans specify its
use.

Plenty of metal planes out there that you don't have to use it.

Yes, and aluminum is a heck of a lot lighter when the part is
finished. I've read in a Glasair, if it were built in aluminum, it
would weigh 400 lbs lighter. That's a typical penalty for building in
regular glass/foam/resin.

On Tue, 20 May 2008 09:19:25 -0700 (PDT), Reggie
wrote:



There are some reasons, this URL supplies some of them.
Especially note the repair risks and the liquid styrene risks


http://www.redrockstore.com/resin.htm


A short reprint of the major points follows, but a review of the total
article suggested


Epoxy resin is known in the marine industry for its incredible
toughness and bonding strength.
Quality epoxy resins stick to other materials with 2,000-p.s.i. vs.
only 500-p.s.i. for
vinylester resins and even less for polyesters.
In areas that must be able to flex and strain WITH the fibers
without micro-fracturing,
epoxy resins offer much greater capability.
Cured epoxy tends to be very resistant to moisture absorption.
Epoxy resin will bond dissimilar or already-cured materials which
makes repair work that is
very reliable and strong.
Epoxy actually bonds to all sorts of fibers very well and also offers
excellent results
in repair-ability when it is used to bond two different materials
together.
Initally, epoxy resin is much more difficult to work with and
requires additional skill
by the technicians who handle it.



Vinylester resins are stronger than polyester resins and cheaper than
epoxy resins.
Vinylester resins utilize a polyester resin type of cross-linking
molecules in the
bonding process.
Vinylester is a hybrid form of polyester resin which has been
toughened with
epoxy molecules within the main moleculer structure.
Vinyester resins offer better resistance to moisture absorption than
polyester resins
but it's downside is in the use of liquid styrene to thin it out (not
good to breath that stuff)
and its sensitivity to atmospheric moisture and temperature.
Sometimes it won't cure if the atmospheric conditions are not right.
It also has difficulty in bonding dissimilar and already-cured
materials.
It is not unusual for repair patches on vinylester resin canoes to
delaminate or peel off.
As vinylester resin ages, it becomes a different resin (due to it's
continual curing as it ages)
so new vinylester resin sometimes resists bonding to your older
canoe,
or will bond and then later peel off at a bad time.
It is also known that vinylester resins bond very well to fiberglass,
but offer a poor bond to kevlar and carbon fibers due to the nature of
those two more exotic fibers.
Due to the touchy nature of vinylester resin, careful surface
preparation is necessary if reasonable adhesion is desired for any
repair work.

That patch peeling you mentioned, I've seen that happen. I used to
keep a boat on a hydrohoist, which had twin tanks made from polyester
resin. I did a repair on it with vinyl ester, and after years of
sitting in the sun, it did just what you mentioned. It turned a brown
and started peeling. Does polyester resin do that? Might be a better
substance for patching and repair work. I've made some laminations
using carbon fiber in vinyl ester, and the parts came out great. No
problems at all. Unless the parts won't age well. Time will tell.
But in these instances, I was creating the parts from scratch, with
the carbon fiber totally emmersed in the resin. Not trying to bond to
an existing carbon fiber part.

On May 20, 9:25*pm, Sliker wrote:
Can't figure it out!!!?? you don't think the odor of amonia is stinky?
I hate to say it, but breathing that epoxy or some other substances
has burned out your olfactory nerves if you don't find Aeropoxy
objectionable. Although, I have used epoxies that smell like the stuff
in those 5 minute tubes. It;'s not that bad. And I just ordered a
different brand, hoping it will not have that amonia odor to it. And
my Aeropoxy has sat around for a while, and the hardner has turned a
deep red color, so all my layups are now deep red. I've read the
manufactures info on that, and they say that's a normal aging effect
of the hardner and dosen't affect the strength. But I wonder if it
make the smell worse.. hmm..


You must be hypersensitive to the amonia smell because the only time I
have noticed it to any degree is if I took a deep whiff from the can.
Even then it is not overly strong. Even my wife, who has the overly
sensitive nose in our household doesn't mind the epoxy odor. The red
coloration is simply an oxidation that occurs in the hardner over time
but hasn't caused any problems with the layups I have seen.

Clearly though, you don't like working with epoxy so my simple advice
would be DON"T. The fact that you don't like it though is not a valid
excuse for condemnation of all things composite or for degrading a
great designer who revolutionized homebuilt design and construction.


In the future if you hate to make a uncalled for comment, don't.

On Tue, 20 May 2008 13:34:58 -0700 (PDT), BobR



wrote:

I can't quite figure out what the heck you are talking about. *I have
worked with epoxy for the last 10 years including Aeropoxy, E-Z Poxy,
West and Hysol. *I can not understand you comment about the "stinky"
part at all. *I will totally agree with you that Vinyl Ester stinks to
the high heavens but have never experienced any such problem with
epoxy formulations. *I can't even stand to work with completed parts
made using the Vinyl Ester but not so with epoxy parts.

I also can't agree with the Toxic comment regarding epoxy since it is
much less toxic than either Vinyl Ester or Polyester Resins.

Guess this is just another case of beauty being in the eye of the
beholder. *I rather enjoy working with composites and prefer them to
working with metals.- Hide quoted text -

- Show quoted text -

On Tue, 20 May 2008 19:51:36 -0700 (PDT), BobR
wrote:


you know if the stuff didn't smell so bad, or take so long to cure, or
wet out the cloth a little better due to it's higher viscosity, I
might be in the group of those who hail the stuff. But I can't get by
it's negatives. And am amazed at how many homebuilders are willing to
put up with the stuff. And to top it off, it's twice as expensive. The
only part of the vinyl ester resin I don't like is the DMA accelerator
that is added to it when it's promoted. And it's amonia based. But the
promotion is only done when a new batch of resin is promoted, not that
often for me. With epoxies, you get to smell amonia every time you use
the stuff. I'm stuck using epoxy for a while, due to some parts I have
that are made out of epoxy, and it's needed to bond them to the
fuselage. Epoxy will stick to vinyl ester, but not the other way
around. So I've heard. I also bought one of those baggage pods the EZ
guys mount to the wings ( or draggage pods ). And they are all epoxy,
and require quite a few layups out of epoxy. So that's where I'm
really getting into using the stuff. Fortunately, I'm nearly finished,
and can go back to using vinyl ester and it's nice sweet smell. I'm
mounting the EZ pod on the belly of my homebuilt (just one) with the
curvature on the bottom, instead of the top like the EZ's mount them.


You must be hypersensitive to the amonia smell because the only time I
have noticed it to any degree is if I took a deep whiff from the can.
Even then it is not overly strong. Even my wife, who has the overly
sensitive nose in our household doesn't mind the epoxy odor. The red
coloration is simply an oxidation that occurs in the hardner over time
but hasn't caused any problems with the layups I have seen.

Clearly though, you don't like working with epoxy so my simple advice
would be DON"T. The fact that you don't like it though is not a valid
excuse for condemnation of all things composite or for degrading a
great designer who revolutionized homebuilt design and construction.


In the future if you hate to make a uncalled for comment, don't.

For me health is a major issue. I am extremely allergic to it.


To which one?

Epoxy.

Allergic reactions to contact and also aromatics. Even 1-2% in paints
will cause reactions. Redness in skin, swelling in face and eyes to
point not able to see, extreme itching etc. It is the hardener, once
cured not a problem.

On May 21, 10:31*am, bizguy wrote:
For me health is a major issue. *I am extremely allergic to it.

To which one?

Epoxy.

Allergic reactions to contact and also aromatics. *Even 1-2% in paints
will cause reactions. *Redness in skin, swelling in face and eyes to
point not able to see, extreme itching etc. *It is the hardener, once
cured not a problem.

You are the first that I have heard of with an allergic reaction to
Epoxy. Met several with reactions to Vinyl Ester. Odd how different
people have totally differing reactions to different things. Vinyl
Ester causes me problems with the dust from any sanding on the parts
but no such reaction from Epoxy. I only had one exposure to Vinyl
Ester in the pre-cure aromatics and had a similar reaction.

On May 20, 10:05*pm, Sliker wrote:
On Tue, 20 May 2008 19:51:36 -0700 (PDT), BobR

wrote:

you know if the stuff didn't smell so bad, or take so long to cure, or
wet out the cloth a little better due to it's higher viscosity, I
might be in the group of those who hail the stuff. But I can't get by
it's negatives. And am amazed at how many homebuilders are willing to
put up with the stuff.

I will just have to assume that the smell is something that some have
a problem with while others don't You have a problem with EPOXY smell
and I have the same problem with the Vinyl Ester. If I had to do any
major work with the VE my wife and I both would have put and end to it
early on. Never have experienced your problems with the wet out and
the cure time is totally a factor of which hardner you use. I can
agree on some layups a shorter cure time would be nice but overall, I
have appreciated the longer cure times when working on larger
projects.

And to top it off, it's twice as expensive. The
only part of the vinyl ester resin I don't like is the DMA accelerator
that is added to it when it's promoted. And it's amonia based. But the
promotion is only done when a new batch of resin is promoted, not that
often for me. With epoxies, you get to smell amonia every time you use
the stuff. I'm stuck using epoxy for a while, due to some parts I have
that are made out of epoxy, and it's needed to bond them to the
fuselage. Epoxy will stick to vinyl ester, but not the other way
around. So I've heard. I also bought one of those baggage pods the EZ
guys mount to the wings ( or draggage pods ). And they are all epoxy,
and require quite a few layups out of epoxy. So that's where I'm
really getting into using the stuff. Fortunately, I'm nearly finished,
and can go back to using vinyl ester and it's nice sweet smell. I'm
mounting the EZ pod on the belly of my homebuilt (just one) with the
curvature on the bottom, instead of the top like the EZ's mount them.

Get a good carbon filter mask, some gloves, and good ventilation.

GOOD LUCK and try to have fun anyway.



You must be hypersensitive to the amonia smell because the only time I
have noticed it to any degree is if I took a deep whiff from the can.
Even then it is not overly strong. *Even my wife, who has the overly
sensitive nose in our household doesn't mind the epoxy odor. *The red
coloration is simply an oxidation that occurs in the hardner over time
but hasn't caused any problems with the layups I have seen.

Clearly though, you don't like working with epoxy so my simple advice
would be DON"T. *The fact that you don't like it though is not a valid
excuse for condemnation of all things composite or for degrading a
great designer who revolutionized homebuilt design and construction.

In the future if you hate to make a uncalled for comment, don't.- Hide quoted text -

- Show quoted text -