Claudia I Franco on thu 11 jan 07
I have several bowls made from glass that have a beautiful carved surface
on the outside of the bowl. I would like to make some sort of bowl using
the outside of the bowl in the inside of a bowl. I have tried using brush
on latex, which captured the detail wonderfully, but when I poured plaster
into latex, the decorative surface doesn=92t cure. Is there any way this
technique is possible or am I wasting my time? I often find surfaces I
wish to replicate but they are always on the wrong side. I am willing to
use rubber/plastic products, but finding the correct one for the job has
been a daunting task. There are no distributors of such products (Smooth-
On is the only one I know of) in Houston with whom I can consult. Any
help will be really appreciated.
Thanks
Claudia
Craig Clark on fri 12 jan 07
Claudia, I have been working a good bit with casting and mold making. I
have been using plaster, alginate, latex and clay. I can answer your
question and have a few suggestions, but a phone conversation is much
less time consuming than trying to write everything out especially since
I do not know about your specific situation. Give me a call if you don't
get an answer in print.
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Claudia I Franco wrote:
> I have several bowls made from glass that have a beautiful carved surface
> on the outside of the bowl. I would like to make some sort of bowl using
> the outside of the bowl in the inside of a bowl. I have tried using brush
> on latex, which captured the detail wonderfully, but when I poured plaster
> into latex, the decorative surface doesn’t cure. Is there any way this
> technique is possible or am I wasting my time? I often find surfaces I
> wish to replicate but they are always on the wrong side. I am willing to
> use rubber/plastic products, but finding the correct one for the job has
> been a daunting task. There are no distributors of such products (Smooth-
> On is the only one I know of) in Houston with whom I can consult. Any
> help will be really appreciated.
> Thanks
> Claudia
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
Gayle Bair on fri 12 jan 07
Claudia,
Why not just make a plaster mold? If the design is on the "wrong" side
make another plaster mold from the original mold.
Gayle Bair - definitely no master!
Bainbridge Island, WA
Tucson, AZ
www.claybair.com
-----Original Message-----
From: Claudia I Franco
Sent: Thursday, January 11, 2007 9:32 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Making Molds question for the Masters
I have several bowls made from glass that have a beautiful carved surface
on the outside of the bowl. I would like to make some sort of bowl using
the outside of the bowl in the inside of a bowl. I have tried using brush
on latex, which captured the detail wonderfully, but when I poured plaster
into latex, the decorative surface doesn't cure. Is there any way this
technique is possible or am I wasting my time? I often find surfaces I
wish to replicate but they are always on the wrong side
Kathy McDonald on fri 12 jan 07
Claudia,
You are right, there are a lot of epoxies, resins and such
out there.
I find nothing quite captures the detail as well as pottery
plaster
when making molds to use as duplicates. The paint on latex
and such just
did not stand up to the process, and I found my few
experiments
with epoxies were expensive and produced master molds that
were only
good for making other plaster molds.
I am not a master mold maker but have been doing a fair
amount of
experimenting with mold making including the technique that
you
are describing. I used bowls that I was willing to
sacrifice.
I haven't broken a bowl or tile yet. .
The most successful of these efforts has been achieved as
follows-
1) Spray the outside surface of the bowl with WD 40
generously.
Bowl must be very clean no moisture.
2) Roll 2 thick slabs of porcelain clay , about 1 in thick
each.
3) Trace a circle the approximate diameter of your bowl in
each of these slabs.
4) Place your bowl on a bat upside down so you can flip
it later
5) lay the first slab on the bowl and work it into the
clay then lay the second slab
over that and gently work that over the first..
The two slabs are necessary for the durability of
the clay mold when its later used for a master plaster cast.
6) Let this clay sit for about 2-4 hours until it just
starts to stiffen
so you don't lose the shape of the bowl because the clay
"flops" but not so stiff that it
might start to crack . This next step is the most difficult
part of the process and cannot
be hurried.
6) Turn the bowl and clay over into another bowl about the
same size and shape
as your original, and then let it dry until you can pull out
the
original in one upward pull. I find that a pin tool can
break the seal all
the way around the clay and only leaves a small distortion
that can be smoothed later.
7) Lift out the original. Try for one pull up no downward
pressure.
This is why the WD 40. Nothing else seems to work as well.
The other bowl acts as protection from too much slumping of
the clay if
it's not quite dry enough.
8) Let this dry to leather hard, if its much harder then it
starts to crack
or shrink too much.
)Now you have a leather hard thick bowl with the outside
decoration on the inside.
Keep it in the protective bowl . I've had some icky plaster
overflows that ruined a lot
of work and plaster when I missed this step.
9) mix your plaster ,about enough to fill the bowl 3/4 full.
Find something that you can use to displace the plaster
after your put it in the bowl. I use those round Styrofoam
balls
that you get at craft stores cut in 1/2. I like the plaster
to be about 1-2 inches thick.
You can tell by watching how much the plaster displaces and
you push in the Styrofoam.
10) Pour the plaster about 1/2 full into the leather hard
mold, use the smaller Styrofoam
shape to displace the plaster and push it up to the rim of
the bowl. This is tricky and you may need to add a bit more
plaster to get it full but better too little plaster the
first time then add more or you end up with some very heavy
molds. The leather hard clay will last just
long enough for #1 Pottery Plaster to set.
11) once the plaster has set remove the Styrofoam ball ..I
do this as soon as you can't
leave a finger print in the plaster. sometimes they come out
easily. sometimes you have to cut them out.
12)once plaster is hard flip it all over onto a bat then
peel off the clay.
You now have a dual purpose mold. A hump mold for the detail
work and when flipped
a slump mold for a smaller bowl. (where the Styrofoam was.)
I am finding that
people seem to like both,,,the bowls made in the slump have
a wonderful outside
texture that looks great when fired.
One thing I cannot emphasize enough is to use porcelain clay
for the mold making process.
Stoneware has too much grit and it gets in the way of
capturing the detail.
Seems complicated but it really isn't. The results are
worth it, I will try
to post some pictures of finished bowls on my photo site
after next firing.
Kathy
7
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of
Claudia I
Franco
Sent: Thursday, January 11, 2007 10:32 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Making Molds question for the Masters
I have several bowls made from glass that have a beautiful
carved surface
on the outside of the bowl. I would like to make some sort
of bowl using
the outside of the bowl in the inside of a bowl. I have
tried using brush
on latex, which captured the detail wonderfully, but when I
poured plaster
into latex, the decorative surface doesn=92t cure. Is there
any way this
technique is possible or am I wasting my time? I often find
surfaces I
wish to replicate but they are always on the wrong side. I
am willing to
use rubber/plastic products, but finding the correct one for
the job has
been a daunting task. There are no distributors of such
products (Smooth-
On is the only one I know of) in Houston with whom I can
consult. Any
help will be really appreciated.
Thanks
Claudia
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John Rodgers on fri 12 jan 07
Visit Polytek at www.polytek.com. Get their catalog Tells you everything
that you want to know.
Get a copy of "Moldmaking for Ceramics" by Donald Frith. The definitive
book on moldmaking. Tells you everything you want to know.
Good luck,
John Rodgers
Chelsea, AL
Claudia I Franco wrote:
> I have several bowls made from glass that have a beautiful carved surface
> on the outside of the bowl. I would like to make some sort of bowl using
> the outside of the bowl in the inside of a bowl. I have tried using brush
> on latex, which captured the detail wonderfully, but when I poured plaster
> into latex, the decorative surface doesn’t cure. Is there any way this
> technique is possible or am I wasting my time? I often find surfaces I
> wish to replicate but they are always on the wrong side. I am willing to
> use rubber/plastic products, but finding the correct one for the job has
> been a daunting task. There are no distributors of such products (Smooth-
> On is the only one I know of) in Houston with whom I can consult. Any
> help will be really appreciated.
> Thanks
> Claudia
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
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