jesse hull on sun 10 apr 05
Paul asked:
Do you know the chemical name for V-Gum?
-----------
Paul, do you mean the chemical formula?
Either way no, I don't off the top of my head, but I
can get it from the glaze chem. binder in my studio
later. It's basically a magnesium-silicate I think,
akin to the Bentonite family. It's closer to macaloid
(also w/i that family) because of the level of purity.
Bentonite's formula is:
AL2O3. 5SIO2. 7H2O
I'd be curious to check on the difference b/t
Bentonite, Macaloid, and V-gum ("T" or otherwise) as
well. -I've been playing with porcelain and
porcelaneous stoneware for years, but I'm still amazed
at how much water magnesium-silicates require.
I currently use a refractory porcelain body that I can
cast, extrude, or throw without any of the problems
normally associated with pure porcelains. I modified
it from a formula given to me by David Pier during his
KCAI days. It normally works really well for me, but
I recently overdeflocculated 20 gal. of the slip
version. I'd added a little more V-Gum T due to the
increase in alumina, molochite, and other
non-plastics. Hindsight tells me I should have just
added more water to the slip to compensate for the
raised V-Gum levels. Live and learn... I keep
hearing how overdeflocculated clay is a nightmare to
balance out, so now I've got to decide whether to try
and fix it or toss it and start over.
~jesse hull.
-----Original Message-----
From: jesse hull [mailto:claytyme@YAHOO.COM]
Sent: Friday, April 08, 2005 7:08 PM
Subject: V-Gum CER: Laguna Clay Co.
Dan,
I had trouble a while back obtaining V-Gum CER. I
find it the best for holding glazes with little clay
content (such as crystallines) both in suspension and
on the form for handling.
I liked it so much, I went in on a 5 gallon bucket of
it with some friends (the smallest qty. I could
locate)...
I must have overlooked it somehow at the time, but
Laguna Clay Co. lists it in their catalogue.
Otherwise, the mixture is 72% V-Gum and 28% CMC. It's
only a bit more of a hassle, and works just as well.
John or Juan @ Laguna can answer any questions.
Hope that helps...
~jesse hull.
Ceramic Design Group on sun 10 apr 05
If I remember correctly, VGums, Macaloid, etc are beneficiated hydrous
magnesium silicates. They are highly refined bentonites which are sub
groups of montmorillinites and smectites.
So why beneficiation? Remember junior high school Latin? "Bene" equals
better. So basically, the process of beneficiation makes the product
better. The processes themselves are all proprietary to each
manufacturer and I think what we need to know is that additions of
these materials make our glazes and clays better. They burn out white
and leave no residue. They are also more expensive then the regular
bentonites we can by from the ceramics materials suppliers.
There are also other bentonites, and yes there are alot of them,
hectorites, of which there is a proprietary one called Hectalite,
another one of those very white bentonites that is a good addition to a
porcelain composition.
I'll certainly stand corrected on my geology if any one else wants to
jump in and correct.
Best
Jonathan
Jonathan Kaplan
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
(970) 879-9139
Plant location for commercial deliveries excluding USPS
1280 13th Street Suite K
Steamboat Springs CO 80487
info@ceramicdesigngroup.net
www.ceramicdesigngroup.net
Hank Murrow on sun 10 apr 05
On Apr 10, 2005, at 3:43 PM, Ceramic Design Group wrote:
> If I remember correctly, VGums, Macaloid, etc are beneficiated hydrous
> magnesium silicates. They are highly refined bentonites which are sub
> groups of montmorillinites and smectites.
> I'll certainly stand corrected on my geology if any one else wants to
> jump in and correct.
No need for correction from me, yet I would add that such clays with an
extra silica lattice are always formed in a saline environment
(estuaries, etc). We have a lot of them along the Oregon Coast, whose
estuaries are 'drowned' from the Pacific plate diving under the coastal
plates.
Cheers, Hank
| |
|
