Hey Karl,

What is Cabosil??

Brian Lawson,
Bothwell, Ontario.
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On Wed, 27 Aug 2003 01:34:48 GMT, "Karl Townsend"
wrote:

I've subscribed to HSM magazine for years. More often than not, I thumb
through it for 30 minutes and say, "nothing for me this time."

This month's article on working with brass and aluminum sheets is one of
the best I've seen in a long while. I don't do a lot of this and learned
lots of new tricks.

There's also a recipe for removing caked on gunk from that used machine you
brought home:

1 pint radiator flush
1 pint engine cleaner
1 pint synthetic cutting fluid
1 pint mineral spirits
2 tablespoons wax
4 tablespoons dishwashing detergent
Cabosil as required to thicken mixture

brush on machine, soak overnight, scrub off. Repeat if needed.

I got to try this one. (I wasted days cleaning up a surface grinder last
year)

Brian Lawson wrote:

Hey Karl,

What is Cabosil??

A thixotropic agent for resin. A thickener, sortof.

Cheers
Trevor Jones

On Wed, 27 Aug 2003 07:38:23 -0400, Brian Lawson
wrote:

Hey Karl,

What is Cabosil??

Cabosil thickening agent for fluids. Me thinks I heard its hollow
glass
beads, almost microscopic. HSM says get it at www.eagerplastics.com
catalog
number EP7965. I bought some at Bumper to Bumper, its used to fill
epoxy
resin for thickening also.

P.S. I own a good 200 F pressure washer. It wouldn't touch the gunk on
that
surface grinder last year.

Karl

"Trevor Jones" wrote in message
...
Brian Lawson wrote:

Hey Karl,

What is Cabosil??

A thixotropic agent for resin. A thickener, sortof.

Yes, fumed silicon dioxide. It's been used to thicken ketchup, so it's not
exactly a hazard. However, you don't want to breath the suspended powder.

Mix some with a strong lye solution and it makes a good, cheap paint
stripper for oil-based paints. It's also great for modifying resins so
they'll stick better on vertical surfaces.

Ed Huntress

Hey Karl,

OK. Thanks. sounds like what West Systems calls MicroBalloons.

Brian.
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On Wed, 27 Aug 2003 07:39:46 -0500, Karl Townsend
wrote:

On Wed, 27 Aug 2003 07:38:23 -0400, Brian Lawson
wrote:

Hey Karl,

What is Cabosil??

Cabosil thickening agent for fluids. Me thinks I heard its hollow
glass
beads, almost microscopic. HSM says get it at www.eagerplastics.com
catalog
number EP7965. I bought some at Bumper to Bumper, its used to fill
epoxy
resin for thickening also.

P.S. I own a good 200 F pressure washer. It wouldn't touch the gunk on
that
surface grinder last year.

Karl

Ed Huntress wrote:
[re cabosil] ...
Yes, fumed silicon dioxide. ...

More than you want to know about it:
http://www.eagerplastics.com/cab.htm

$12/gal (1/2lb), $18/2-gal (1 lb). It looks like shipping is the actual
UPS charge.

Any feeling for how much you'd use in a gallon of lye?

Bob

"Brian Lawson" wrote in message
...
Hey Karl,

OK. Thanks. sounds like what West Systems calls MicroBalloons.

WEST System microballoons are phenolic resin bubbles. No relation to
Cab-O-Sil. I have tubs of both in my basement right now. Both are great
additives for epoxy or vinylester resins, and the microballoons are useful
with polyester. Cab-O-Sil, less so.

Cab-O-Sil is a thixotropic agent. Phenolic microballoons are used primarily
to reduce weight. The microballoons do help resin to stay in place on
vertical surface, but they don't actually make it thixotropic. They just
make it stiffer and lighter.

Ed Huntress

"Bob Engelhardt" wrote in message
...
Ed Huntress wrote:
[re cabosil] ...
Yes, fumed silicon dioxide. ...

More than you want to know about it:
http://www.eagerplastics.com/cab.htm

$12/gal (1/2lb), $18/2-gal (1 lb). It looks like shipping is the actual
UPS charge.

Any feeling for how much you'd use in a gallon of lye?

Bob


Sorry, I haven't mixed any for a while. The complete formula, used by some
antique house restorers, includes diatomaceous earth (pool filtering
material). You make a strong batch of lye, toss in diatomaceous earth until
it starts to get pretty muddy, and then add Cab-O-Sil (that's the trademark
name; there are others) until it's smooth and seems to hang on vertical
surfaces. The DE greatly reduces the amount of Cab-O-Sil you need for the
job, and it's a lot cheaper.

I got the formula from one of two places, neither of which is handy. If I
come across them I'll post it.

Ed Huntress

Ed Huntress wrote:
... add Cab-O-Sil ... until it's smooth and seems to hang on vertical
surfaces. ...

Yeah, my general shop model would handle it that way. It's also known
as TLAR ( That Looks About Right). I was interested in more specific
quantities just to figure how much to order.

I got the formula from one of two places, neither of which is handy. If I
come across them I'll post it.


Thanks.
Bob

The standard technical terms used by boat builders for viscosity
measurements of fumed silica thickened resins a

Catsup
Mayonnaise
Penut butter

:-)

Bob Engelhardt wrote:
Ed Huntress wrote:

... add Cab-O-Sil ... until it's smooth and seems to hang on vertical
surfaces. ...


Yeah, my general shop model would handle it that way. It's also known
as TLAR ( That Looks About Right). I was interested in more specific
quantities just to figure how much to order.


I got the formula from one of two places, neither of which is handy. If I
come across them I'll post it.



Thanks.
Bob


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Glenn Ashmore" wrote in message
...
The standard technical terms used by boat builders for viscosity
measurements of fumed silica thickened resins a

Catsup
Mayonnaise
Penut butter

Probably named by a condiment merchant.

Ed Huntress

On Wed, 27 Aug 2003 20:10:22 GMT, "Ed Huntress"
wrote:


"Glenn Ashmore" wrote in message
...
The standard technical terms used by boat builders for viscosity
measurements of fumed silica thickened resins a

Catsup
Mayonnaise
Peanut butter

Probably named by a condiment merchant.

Ed Huntress

Glenn's not kidding- those are the actual terms Gougen Brothers (WEST
System) use for defining thickened epoxy. 'Peanut butter' will stick
to the ceiling.
Unthickened epoxy is pretty thin and is called 'neat'.

Epoxy thickened with fumed silica is called 'dookie', epoxy thickened
with wood flour is called 'schmutz' (or is it the other way around?)
and epoxy thickened with both is called 'dookie schmutz'. Dookie
schmutz is incredibly handy stuff- think 'ultra strong plastic wood'
(dookie schmutz is Coast Guard approved for fillet-bonding wood
boats).

One corner of the sliding-glass door frame on my house had some pretty
nasty rot happening. A conventional repair would have involved
dismantling the door casing. Instead, I Sawzalled the rotten parts
out, epoxied in new wood and schmutzed and sanded the seams. Took
about an hour and has held up for five years so far.

Everyone should keep a couple of quarts of marine epoxy on hand. Great
stuff.

-Carl

On Wed, 27 Aug 2003 01:34:48 GMT, "Karl Townsend"
wrote:

I've subscribed to HSM magazine for years. More often than not, I thumb
through it for 30 minutes and say, "nothing for me this time."

This month's article on working with brass and aluminum sheets is one of
the best I've seen in a long while. I don't do a lot of this and learned
lots of new tricks.

I didn't agree with some of the assertions in that article about
difficulty in soldering/brazing thin aluminum sheetmetal. It's not
quite as easy as soldering brass, but it's not difficult. HVAC
technicians routinely solder or braze aluminum refrigeration tubing.

I've gotten exellent results with two materials: one is Esab #31 rod
with their #31 flux and the other is some rod and flux I got from
http://www.tinmantech.com/html/aluminum_aero_braze.html

The Esab stuff, designed for HVAC work, works best on thinner
materials, as up to .040" or so. It wets and runs like silversolder
does on brass if the work is clean, fluxed, and heated slowly and
evenly under the flame, just as the HSM article suggests as a good
procedure for soldering brass.

The tinman's stuff works better on thicker sheetmetal, like .030 to
???. I'd weld anything over .062 thick with torch or TIG but that's
beyond the scope of the HSM article.

A skilled weldor with good equipment can TIG-weld very thin aluminum.
I'm not highly skilled and I don't have such equipment, but I have no
problem making nice joints in aluminum sheetmetal with a torch and
the materials mentioned above.

I'd recommend a silver-bearing alloy over lead-tin solder for work
with brass or steel. Harris Staybrite works very well, runs below
500F and is much stronger than soft solder. It also works well on
staineless steel.

I'm merely reporting my experience, YMMV.

Glenn's not kidding- those are the actual terms Gougen Brothers (WEST
System) use for defining thickened epoxy. 'Peanut butter' will stick
to the ceiling.
Unthickened epoxy is pretty thin and is called 'neat'.

Epoxy thickened with fumed silica is called 'dookie', epoxy thickened
with wood flour is called 'schmutz' (or is it the other way around?)
and epoxy thickened with both is called 'dookie schmutz'. Dookie
schmutz is incredibly handy stuff- think 'ultra strong plastic wood'
(dookie schmutz is Coast Guard approved for fillet-bonding wood
boats).

Egads. How quickly jargon takes on a life of its own. I don't remember those
terms, and I hung around the Gougeon Bros. shop quite a lot in the early
'70s.

Ed Huntress