Cab-o-Sil -- which type to use?

I called the Cabot Corporation, which manufactures Cab-o-Sil, to get
information about their products. They were amazed that fly fishermen
were using this stuff for drying flies, and were kind enough to send me
samples of both hydrophobic and hydrophilic products to test. (I now
have several lifetimes' supply -- about two quarts of each.)

The two kinds of Cab-o-Sil that I tested we

M-5 untreated fumed silica, hydrophobic

TS-720 treated fumed silica, hydrophilic

The result in a nutshell is that the treated, hydrophobic TS-720 product
is the one to use. The untreated, hydrophilic M-5 is worse than useless.
It turns into a gooey mess when wet and causes the fly to sink. The
TS-720 works great. After I dried a completely soaked fly with it, the
fly floated better than even a fresh, untreated, completely dry fly.

--
Cut "to the chase" for my email address.

rw wrote:
I called the Cabot Corporation, which manufactures Cab-o-Sil, to get
information about their products. They were amazed that fly fishermen
were using this stuff for drying flies, and were kind enough to send me
samples of both hydrophobic and hydrophilic products to test. (I now
have several lifetimes' supply -- about two quarts of each.)

The two kinds of Cab-o-Sil that I tested we

M-5 untreated fumed silica, hydrophobic

TS-720 treated fumed silica, hydrophilic

Oops. Correction: The untreated M-5 is hydrophilic and the treated
TS-720 is hydrophobic. The next paragraph is correct.

The result in a nutshell is that the treated, hydrophobic TS-720 product
is the one to use. The untreated, hydrophilic M-5 is worse than useless.
It turns into a gooey mess when wet and causes the fly to sink. The
TS-720 works great. After I dried a completely soaked fly with it, the
fly floated better than even a fresh, untreated, completely dry fly.

Use the hydrophobic stuff.

--
Cut "to the chase" for my email address.

rw wrote:
rw wrote:
The result in a nutshell is that the treated, hydrophobic TS-720
product is the one to use. The untreated, hydrophilic M-5 is worse
than useless. It turns into a gooey mess when wet and causes the fly
to sink. The TS-720 works great. After I dried a completely soaked fly
with it, the fly floated better than even a fresh, untreated,
completely dry fly.

Use the hydrophobic stuff.

So Dickie Dean was right. Credit where credit's due.

--
Ken Fortenberry

Dang that's awesome. Save me some of the hydrophobic, which I could
never find. My big jars are (were) hydrophilic. I'd also like the
instructions for ordering hydrophobic Cab-O-Sil in retail quantities.
Hopefully they'll send you a Cab-O-Sil shirt too! bh

"bruiser" wrote in message
oups.com...
Dang that's awesome. Save me some of the hydrophobic, which I could
never find. My big jars are (were) hydrophilic. I'd also like the
instructions for ordering hydrophobic Cab-O-Sil in retail quantities.
Hopefully they'll send you a Cab-O-Sil shirt too! bh

What is Cab-O-Sil used for and where do you get it?

"JakBQuik" wrote in message
...

"bruiser" wrote in message
oups.com...
Dang that's awesome. Save me some of the hydrophobic, which I could
never find. My big jars are (were) hydrophilic. I'd also like the
instructions for ordering hydrophobic Cab-O-Sil in retail quantities.
Hopefully they'll send you a Cab-O-Sil shirt too! bh

What is Cab-O-Sil used for and where do you get it?

http://www.google.com/search?hl=en&q...=Google+Search

bruiser wrote:
Dang that's awesome. Save me some of the hydrophobic, which I could
never find.

I could send you some if you can't wait until we meet up in Alaska.
(You won't be using much Cab-o-Sil in Alaska.)

My big jars are (were) hydrophilic.

Jesus. I hope you haven't been using it.

I'd also like the
instructions for ordering hydrophobic Cab-O-Sil in retail quantities.

Well, you can call Cabot, tell them something interesting about their
product that comes as a big surprise to them, and get them to send you a
huge bottle, but I beat you to it. :-)

Hopefully they'll send you a Cab-O-Sil shirt too! bh

I'll ask my contact at Cabot.

--
Cut "to the chase" for my email address.

"rw" wrote in message
m...


Well, you can call Cabot, tell them something interesting about their
product that comes as a big surprise to them, and get them to send you a
huge bottle, but I beat you to it. :-)

rw,
Apparently you didn't run the well dry. In response to an email inquiry
that I made to Cabot's Fumed metal oxide department, I just got an email
telling me that they are sending me a 100g sample of Cab-o-sil TS 720. I
will probably now have supply enough of Frog Fanny substitute for several
lifetimes , as I received the email just after I had ordered 2 qts of it
from the source that Stan named..

Bob Weinberger - La Grande, OR

BTW there' pretty good dry fly action on the "O" right now despite the fact
that its quite off color and still flowing at 3X normal for this time of
year ( until 3 days ago it was flowing at 7 times normal and a few mos. ago
was flowing at almost 300 times normal.).

After playing around with this hydrophobic fumed silicon (Cab-o-Sil
TS-720) I've changed the way I look at this substance. It can be used as
a "fly-drying" agent, which is how I've been using it, and it works very
well for that, but it's also a "waterproofing" agent. The treated fly
floats better than the dry untreated fly. That's because hydrophobic
(water-resisting) particles embedded in the fly repel water molecules.

To get maximum floating performance I'd do this:

1. Treat the fly before fishing it, while it's dry. Immerse the fly in
fumed silicon, twirl it around, rub the particles in, and blow away the
excess. Repeat.

2. After the fly gets wet use a stiff brush to push the substance into
the fly. Use a lot, to excess. The brush that comes in a Frog's Fanny
bottle works great. The substance will push the water to the surface
where it can be shaken off with false casts. Repeat.

A few points:

1. You'll use a lot of the agent this way, so for this to be economical
you need cheap treated fumed silicon, not Frog's Fanny or its imitators.

2. If you want a low-floating fly don't use treated fumed silicon on a
heavily hackled fly.

3. This stuff changes the status quo for tying dry flies. You can tie
very sparse patterns with hydrophilic (water attracting) materials and
still get the fly to float if it traps fumed silicon particles. It could
even be incorporated into recipes. For example, you could mix it into
the dubbing and tie it into the body.

--
Cut "to the chase" for my email address.

rw wrote:
After playing around with this hydrophobic fumed silicon (Cab-o-Sil
TS-720)

For "silicon" substitute "silica" (SiO2).

--
Cut "to the chase" for my email address.