Epoxy is really crap for homebuilding

Lately I've had to use the stuff to work with some pre-made parts that
were made from epoxy. Aeropoxy. Stinky!
Epoxy is more viscose, so it doesn't wet out the cloth as well. It is
more toxic, especially some of the older formulas. And smells
horrible. And why did so many homebuilders get stuck using that crap?
Rutan. Those hot wired, foam core wings and other parts to be exact.
The type of foam that can be hotwired, dissolves when in contact with
vinyl ester or polyester resin. So they had to use epoxy. What they
should have done is figured out another way to cut the foam cores with
something like a wire saw, and used polyurethane foam and vinyl ester
resin. Plus, epoxy is expensive, and much more flameable. So it's use
in aircraft has so many negatives, it should never have been used.
Rutan really put one on us with the epoxy legacy.

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.

"Reggie" wrote in message
...

Isn't cure time also a big factor in more complex lay-ups?

On May 20, 9:52*am, "Maxwell" luv2^fly99@cox.^net wrote:
"Reggie" wrote in message

...

Isn't cure time also a big factor in more complex lay-ups?

It is, but it's not a strong factor either way in the rant at hand.
While commercially available vinylesters are generally pre-promoted
for a working time of around 20 minutes, formulators can (for a price)
supply un-promoted resin, and can also supply it promoted for working
times up to about 2 hours.

Thanks, Bob K.

"Sliker" wrote in message
...
Lately I've had to use the stuff to work with some pre-made parts that
were made from epoxy. Aeropoxy. Stinky!
Epoxy is more viscose, so it doesn't wet out the cloth as well. It is
more toxic, especially some of the older formulas. And smells
horrible. And why did so many homebuilders get stuck using that crap?
Rutan. Those hot wired, foam core wings and other parts to be exact.
The type of foam that can be hotwired, dissolves when in contact with
vinyl ester or polyester resin. So they had to use epoxy. What they
should have done is figured out another way to cut the foam cores with
something like a wire saw, and used polyurethane foam and vinyl ester
resin. Plus, epoxy is expensive, and much more flameable. So it's use
in aircraft has so many negatives, it should never have been used.
Rutan really put one on us with the epoxy legacy.

There are really a couple of issues here.

First, I really don't like the hot wire method of forming foam because of
the fumes that result; but I no longer recall which of the current materials
were available in those days. However, I do seem to recall that the
so-called "Safety-Poxy" which Burt recommended was hailed, at the time, as
something of a breakthrough in both safety and ease of use in a relatively
wide range of working environments.

Second, despite some later crumbling about the dimensioning of interior
bulkheads, Burt's idea was that the Vari-Eze should be extremely easy and
quick to construct. IIRC, two people were supposed to be able to do it in
less than a month--or about 300 man hours total time. When the results
drastically deviated from that concept, Burt went on tour and showed how it
was done. I had the privelege of attenting one of his "hands-on" seminar
demonstrations in Fort Lauderdale at the time--and it was abundantly clear
that, if you learned to work the way he worked, the problems were minimized.

Peter

P.S.: I do agree that there are far better materials available today, and
also better cutting methods; but Burt my point is simply that Burt is not
culpable!

On May 20, 9:27*am, Sliker wrote:
Lately I've had to use the stuff to work with some pre-made parts that
were made from epoxy. Aeropoxy. Stinky!
Epoxy is more viscose, so it doesn't wet out the cloth as well. It is
more toxic, especially some of the older formulas. And smells
horrible. And why did so many homebuilders get stuck using that crap?
Rutan. Those hot wired, foam core wings and other parts to be exact.
The type of foam that can be hotwired, dissolves when in contact with
vinyl ester or polyester resin. So they had to use epoxy. What they
should have done is figured out another way to cut the foam cores with
something like a wire saw, and used polyurethane foam and vinyl ester
resin. Plus, epoxy is expensive, and much more flameable. So it's use
in aircraft has so many negatives, it should never have been used.
Rutan really put one on us *with the epoxy legacy.

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 May 20, 3:34 pm, BobR wrote:
On May 20, 9:27 am, Sliker wrote:

Lately I've had to use the stuff to work with some pre-made parts that
were made from epoxy. Aeropoxy. Stinky!
Epoxy is more viscose, so it doesn't wet out the cloth as well. It is
more toxic, especially some of the older formulas. And smells
horrible. And why did so many homebuilders get stuck using that crap?
Rutan. Those hot wired, foam core wings and other parts to be exact.
The type of foam that can be hotwired, dissolves when in contact with
vinyl ester or polyester resin. So they had to use epoxy. What they
should have done is figured out another way to cut the foam cores with
something like a wire saw, and used polyurethane foam and vinyl ester
resin. Plus, epoxy is expensive, and much more flameable. So it's use
in aircraft has so many negatives, it should never have been used.
Rutan really put one on us with the epoxy legacy.

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.

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.

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.

On May 20, 4:39*pm, bizguy wrote:
On May 20, 3:34 pm, BobR wrote:





On May 20, 9:27 am, Sliker wrote:

Lately I've had to use the stuff to work with some pre-made parts that
were made from epoxy. Aeropoxy. Stinky!
Epoxy is more viscose, so it doesn't wet out the cloth as well. It is
more toxic, especially some of the older formulas. And smells
horrible. And why did so many homebuilders get stuck using that crap?
Rutan. Those hot wired, foam core wings and other parts to be exact.
The type of foam that can be hotwired, dissolves when in contact with
vinyl ester or polyester resin. So they had to use epoxy. What they
should have done is figured out another way to cut the foam cores with
something like a wire saw, and used polyurethane foam and vinyl ester
resin. Plus, epoxy is expensive, and much more flameable. So it's use
in aircraft has so many negatives, it should never have been used.
Rutan really put one on us *with the epoxy legacy.

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.

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.- Hide quoted text -

- Show quoted text -

To which one? Vinyl Ester has caused substantial alergic problems but
I haven't seen anyone experience the same with the epoxy
formulations. In any case, I can understand your problem. I have
received a couple of parts built with the Vinyl Ester and even sanding
it cause symptoms similar to asthma but I have never experienced any
problems with epoxy and I rarely use gloves when working with it.

On May 20, 4:42*pm, 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.

Or tube and fabric. Don't forget wooden plans such as the Falco.