Cotton flox in resin

I have a question some of you Epoxy builders might know. Is Cotton
Flox okay to use as a structural filler in vinyl ester resin?. And if
so, why is it not called for to be used in it? Mostly, micro balloons,
cabosil, and milled fibers are used in vinyl ester, but in epoxy they
use cotton flox. I can think of a few uses where cotton flox would be
nice to use. I'm just can't find any info say whether or not it's
compatiable with vinyl ester resin.

Ted wrote:
I have a question some of you Epoxy builders might know. Is Cotton
Flox okay to use as a structural filler in vinyl ester resin?. And if
so, why is it not called for to be used in it? Mostly, micro balloons,
cabosil, and milled fibers are used in vinyl ester, but in epoxy they
use cotton flox. I can think of a few uses where cotton flox would be
nice to use. I'm just can't find any info say whether or not it's
compatiable with vinyl ester resin.

In epoxy adhesive, cotton flox is used to thicken the uncured adhesive
(to keep it from running). Microballoons are used to maintain some
separation between the mating surfaces (mostly so the adhesive isn't
completely squeezed out but sometimes to prevent contact between
dissimilar metals). I suppose either is useful for thinning the
adhesive if bond strength isn't critical.

I realize this doesn't address your question about vinyl ester, just
some of the reasoning behind epoxy. Hope that helps a little...

Ted wrote:

I have a question some of you Epoxy builders might know. Is Cotton
Flox okay to use as a structural filler in vinyl ester resin?. And if
so, why is it not called for to be used in it? Mostly, micro balloons,
cabosil, and milled fibers are used in vinyl ester, but in epoxy they
use cotton flox. I can think of a few uses where cotton flox would be
nice to use. I'm just can't find any info say whether or not it's
compatiable with vinyl ester resin.

Dunno Ted,

use glass microspheres for epoxy.
use pheonolic microspheres for 'esters.

Unless it's something like that, I can't see any reason not to use cotton.

Of course, it will probably prove to be exactly that - so go figure.


Richard

you could do a small test part. even when the parts of the equation
are "proven" and/or "as directed" a little experiment for Q&A is done
now and then...kinda like scratching the resin left over in the cup.

On 2 Apr 2006 23:35:02 -0700, "
wrote:

my impression was ballons and flox bring only physical contributions to
the mix....and therefore substituting balloons with flox would fill AND
strengthen a joint, but do no harm. In all my composites training, the
only no-no I heard was to use merely balloons when flox was called for,
and I'm sure you knew that already.

Not really, I have no experience with flox at all. But it's properties
seem to be that it's stronger than microballoons. I would suspect it's
also heavy, so has a weight penalty compared to micro. I'm going to
bond some epoxy made wing fillets to the fuselage of my Glasair 3. And
would like to mix in some flox. But in this case, I'll be bonding with
AeroPoxy, and use the flox to thicken it. But since I'll have some
flox left over, I'm going to see how it mixes with vinyl ester for
later use.
Ted

Ted wrote:
On 2 Apr 2006 23:35:02 -0700, "
wrote:

my impression was ballons and flox bring only physical contributions to
the mix....and therefore substituting balloons with flox would fill AND
strengthen a joint, but do no harm. In all my composites training, the
only no-no I heard was to use merely balloons when flox was called for,
and I'm sure you knew that already.

Not really, I have no experience with flox at all. But it's properties
seem to be that it's stronger than microballoons. I would suspect it's
also heavy, so has a weight penalty compared to micro. I'm going to
bond some epoxy made wing fillets to the fuselage of my Glasair 3. And
would like to mix in some flox. But in this case, I'll be bonding with
AeroPoxy, and use the flox to thicken it. But since I'll have some
flox left over, I'm going to see how it mixes with vinyl ester for
later use.
Ted

In my use of composites, balloons were used when a very light filler was
needed and flox was used when strength was necessary. The fibers of
flox established a much stronger bond but was heavier than balloons.
The balloon mixture was much easier to sand also.

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Jim Carriere wrote:
Ted wrote:

I have a question some of you Epoxy builders might know. Is Cotton
Flox okay to use as a structural filler in vinyl ester resin?. And if
so, why is it not called for to be used in it? Mostly, micro balloons,
cabosil, and milled fibers are used in vinyl ester, but in epoxy they
use cotton flox. I can think of a few uses where cotton flox would be
nice to use. I'm just can't find any info say whether or not it's
compatiable with vinyl ester resin.


In epoxy adhesive, cotton flox is used to thicken the uncured adhesive
(to keep it from running). Microballoons are used to maintain some
separation between the mating surfaces (mostly so the adhesive isn't
completely squeezed out but sometimes to prevent contact between
dissimilar metals). I suppose either is useful for thinning the
adhesive if bond strength isn't critical.

I realize this doesn't address your question about vinyl ester, just
some of the reasoning behind epoxy. Hope that helps a little...
Eeek! Ok, the deal is cotton flox is used not to thicken (the epoxy will
still run), but to make a moldable structural construct. The micro can
be used for non-structural thickening & the cabosil is used primarily
for thickening. The effects on the resin are as follows:
Cabosil and flox make for heavier structures, flox is typically used for
structural applications (those cute pens you can buy that look like
polished turtle shell are made from it), and micro will make a friable
structure with little or no strength, but light as a feather. It is true
that micro is used to ensure that while bonding two structures some
resin is left between the two parts.


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Hi Ted,

As for any filler, 3 things are critical for its use:

- No chemical interaction with the resin: Will insure that either the
filler or the resin are affected by the other materials and chemicals in
play.

- Good wetability: the filler has to mix with the resin. It must be
wetted easily by the resin. An appropriate surface treatment can be done
if the material itself is not wetable enough.

- Good adhesion with the resin: For obvious strength reasons. Goes not
together with the wetability, so you can create a weak bond if the resin
adhesion with the filler is lost during cure.

The best way is to check if cellulose (cotton is about 100% cellulose)
is affected by the vinyl-ester chemicals, then test if the mix is good
and if the cured resistance is Ok... Then you can probably use it.

From a materials science engineer

Luc

Jeez guys... Just ask anyone who works at a boat factory...Dribble some
catalyzed vinylester resin on your cotton chinos and see if it will
come off (not)... Cotton flox will bond forever with your resin...

denny