Jeff Longtin on sat 5 nov 11
I'll share my adventures in slip casting to shed light on the Darvan
situation.
I first started slip casting in 1984. A potter, with whom I was working,
saw my hand built teapot and said, "You should try slip casting."
The potters I knew, at the time, were aware of my new direction, as were
the local clay companies. I hadn't really thought about "marketing" my
skills but some potters were reaching the "tired of throwing" phase and so =
I was
getting some calls and some business.
Then Don Frith published his book, "Mold Making for Ceramics".
Suddenly lots of potters thought mold making was easy. Then I started
getting lots of calls. Lots of calls asking for advice and lots of calls as=
king
if the Don Frith book was a good reference. By coincidence a neighbor had
bought a copy so I had a chance to read it.
It's a very good book. It's not the "be all end all" but it's very good. I
think it was Don Frith who introduced Darvan and Smooth-On to the studio
ceramics world. (Smooth-On is a urethane rubber casting medium.)
Being full of myself I called these companies and told them that I was
"mold making company". Very soon I had samples of Darvan 7 and Darvan 811 i=
n my
studio. (The Smooth-On rep also sent samples.) The Darvan rep explained
the differences between the two. I was mixing my own porcelain casting sli=
p
at the time so I put them to use. The Darvan 7 didn't seem all that
different from standard sodium silicate but the 811 did seem to thin slips=
much
more easily.
But 811 is much more expensive than standard sodium silicate, if I recall,
so I never used it as a regular practice, in the studio.
take care
Jeff Longtin
Minneapolis
John Rodgers on sat 5 nov 11
Wow, Jeff! Reading this was like reading my own bio - even the "started
slipcasting in 1984" part down to calls about Frith's book, . What a
coincidence!
Included in my learning curve about slipcasting, I tried Darvan 7 - and
- as opposed to sodium silicate - I found in my experience that the
Darvan 7 was slow in getting the slip viscosity up to speed. For me the
silicate performed much faster. But this difference may be why so people
prefer the Darvan. With sodium silicate - a little goes a looooong way -
and it's easy to make a mistake. Darvan is slower to bring to the bottom
of the curve, therefore safer. I've just used sodium silicate so long at
the batch sizes I work with that much prefer the speed of the silicate,
I find the Darvan way to slow., Just my experience.
John
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
On 11/5/2011 6:41 AM, Jeff Longtin wrote:
> I'll share my adventures in slip casting to shed light on the Darvan
> situation.
>
> I first started slip casting in 1984. A potter, with whom I was working,
> saw my hand built teapot and said, "You should try slip casting."
>
> The potters I knew, at the time, were aware of my new direction, as were
> the local clay companies. I hadn't really thought about "marketing" my
> skills but some potters were reaching the "tired of throwing" phase and s=
o I was
> getting some calls and some business.
>
> Then Don Frith published his book, "Mold Making for Ceramics".
>
> Suddenly lots of potters thought mold making was easy. Then I started
> getting lots of calls. Lots of calls asking for advice and lots of calls =
asking
> if the Don Frith book was a good reference. By coincidence a neighbor had
> bought a copy so I had a chance to read it.
>
> It's a very good book. It's not the "be all end all" but it's very good.=
I
> think it was Don Frith who introduced Darvan and Smooth-On to the studio
> ceramics world. (Smooth-On is a urethane rubber casting medium.)
>
> Being full of myself I called these companies and told them that I was
> "mold making company". Very soon I had samples of Darvan 7 and Darvan 811=
in my
> studio. (The Smooth-On rep also sent samples.) The Darvan rep explained
> the differences between the two. I was mixing my own porcelain casting s=
lip
> at the time so I put them to use. The Darvan 7 didn't seem all that
> different from standard sodium silicate but the 811 did seem to thin sli=
ps much
> more easily.
>
> But 811 is much more expensive than standard sodium silicate, if I recal=
l,
> so I never used it as a regular practice, in the studio.
>
> take care
> Jeff Longtin
> Minneapolis
>
>
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