Ama Menec on sun 12 feb 06
Dear Clayarters,
I'd love any feedback from anyone who press moulds clay, or paperclay, into
something other than plaster, particularly on a larger scale. I'm just
finishing making a large and complex piece. Here's the link so you can see
what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should point
out it's the bottom view of the sculpture, not of Ama Menec!) and it's
useful as it shows 2 hands, 2 feet, (all those little digits), and quite a
lot of undercuts. I normally press mould into very hard plaster such as
Herculite or Prestia Creation, and I had resigned myself to casting this as
a 5 piece press mould. I'd worked out the seam lines, (top section and 4
side panels), but still wobbling about how to arrange the order of
assembly/disassembly, when a chance remark from another sculptor friend
brought up another possibility I hadn't considered.
She press moulds paperclay into small latex moulds and says the paperclay
doesn't stick like plain clay would. The items she casts are things such as
bonio biscuits and MacDonald's cartons, I haven't seen anything bigger than
that, and they are supported in turn by a plaster jacket mother mould. Now I
have used rubber moulds with plaster mother moulds in the past when I used
to cast in concrete, but I have never seen anyone using clay this way, or on
a big scale. What I'm curious about is whether a large complex piece would
work just as well this way, if it takes considerably longer to dry to the
point you can take it out, and whether you could make a facing of paperclay
to be in contact with the latex or silicon mould and finish the rest of the
press-moulding using ordinary clay.....
I'd love to hear of anyone who has tried this or seen it done. Many thanks,
Ama, Totnes, Devon, UK.
Centa Uhalde on sun 12 feb 06
Hi Ama and Debbie,
I work sculpturally, and have worked in paper clay but I'm sure I'm not
using it to it's best advantage, yet, and have used press molds for larger
pieces. I haven't used rubber though. Please include me in the discussion
if it goes off line.
Thanks,
Centa
Craig Clark on sun 12 feb 06
Ama, go ahead and do what your friend has suggested. I have done
half torso's and other castings with undercut problems using flexible
rubber molds. They work very well. The only draw back is the mold
material is much more expensive than plaster and you will also incur the
additional cost of plaster bandages to back up and "stiffen" your
flexible mother mold.
To keep the clay from sticking just really coat the rubber with a
good oil soap or vaseline. After you are sure that the clay you have
pressed into your mold has set toward a soft leather state pull the
rubber. From the look of your piece you shouldn't have much of a problem.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St.
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Ama Menec wrote:
>Dear Clayarters,
>
>I'd love any feedback from anyone who press moulds clay, or paperclay, into
>something other than plaster, particularly on a larger scale. I'm just
>finishing making a large and complex piece. Here's the link so you can see
>what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should point
>out it's the bottom view of the sculpture, not of Ama Menec!) and it's
>useful as it shows 2 hands, 2 feet, (all those little digits), and quite a
>lot of undercuts. I normally press mould into very hard plaster such as
>Herculite or Prestia Creation, and I had resigned myself to casting this as
>a 5 piece press mould. I'd worked out the seam lines, (top section and 4
>side panels), but still wobbling about how to arrange the order of
>assembly/disassembly, when a chance remark from another sculptor friend
>brought up another possibility I hadn't considered.
>
>She press moulds paperclay into small latex moulds and says the paperclay
>doesn't stick like plain clay would. The items she casts are things such as
>bonio biscuits and MacDonald's cartons, I haven't seen anything bigger than
>that, and they are supported in turn by a plaster jacket mother mould. Now I
>have used rubber moulds with plaster mother moulds in the past when I used
>to cast in concrete, but I have never seen anyone using clay this way, or on
>a big scale. What I'm curious about is whether a large complex piece would
>work just as well this way, if it takes considerably longer to dry to the
>point you can take it out, and whether you could make a facing of paperclay
>to be in contact with the latex or silicon mould and finish the rest of the
>press-moulding using ordinary clay.....
>
>I'd love to hear of anyone who has tried this or seen it done. Many thanks,
>
>Ama, Totnes, Devon, UK.
>
>______________________________________________________________________________
>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.
>
>
>
Debbie on sun 12 feb 06
Hi Ama,
How interesting and beautiful. I didn't catch how large this piece is?
It would seem we are experimenting along the same lines and I'd love to
share notes with you, on or off list as well as hear form others trying
this.
I have tried pressing regular (non-paper) clay into a RTV mold about 4' with
a plaster, FMG or fiberglass casing. Much to my surprise, it worked....with
some adjustments to the process. Now I'm starting to try more with nylon
fiber reinforced clay. All still very much in the experimental stages but so
far I'm very impressed with the working qualities of the clay and it seems
that this clay might offer advantages for rubber mold pressing as well.
Physically handling very large, heavy and complex greenware is it's own set
of challenges!
My initial thoughts about the RTV is to use as hard a rubber as possible and
keep the rubber mold wall as thin as possible (less squish factor when
applying the clay). Very soft clay seems best, applying layers and allowing
subsequent ones to stiffen a bit. In demolding the piece timing is
everything. I often plan to rework the surface or modify the piece. If the
clay is right for working but still too soft to demold I've had good results
with applying spray foam (insulation in a can) to the inside for instant
support. This can be pulled out latter.
Hope to hear from other intrepid clay explorers on the subject .
Debbie in CA USA
> Subject: Paperclay press moulding into silicon/latex moulds.
>
>
> Dear Clayarters,
>
> I'd love any feedback from anyone who press moulds clay, or
> paperclay, into
> something other than plaster, particularly on a larger scale. I'm just
> finishing making a large and complex piece. Here's the link so you can see
> what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should point
> out it's the bottom view of the sculpture, not of Ama Menec!) and it's
> useful as it shows 2 hands, 2 feet, (all those little digits), and quite a
> lot of undercuts. I normally press mould into very hard plaster such as
> Herculite or Prestia Creation, and I had resigned myself to
> casting this as
> a 5 piece press mould. I'd worked out the seam lines, (top section and 4
> side panels), but still wobbling about how to arrange the order of
> assembly/disassembly, when a chance remark from another sculptor friend
> brought up another possibility I hadn't considered.
>
> She press moulds paperclay into small latex moulds and says the paperclay
> doesn't stick like plain clay would. The items she casts are
> things such as
> bonio biscuits and MacDonald's cartons, I haven't seen anything
> bigger than
> that, and they are supported in turn by a plaster jacket mother
> mould. Now I
> have used rubber moulds with plaster mother moulds in the past when I used
> to cast in concrete, but I have never seen anyone using clay this
> way, or on
> a big scale. What I'm curious about is whether a large complex piece would
> work just as well this way, if it takes considerably longer to dry to the
> point you can take it out, and whether you could make a facing of
> paperclay
> to be in contact with the latex or silicon mould and finish the
> rest of the
> press-moulding using ordinary clay.....
>
> I'd love to hear of anyone who has tried this or seen it done.
> Many thanks,
>
> Ama, Totnes, Devon, UK.
>>
Norman Aufrichtig on sun 12 feb 06
i have also pressed paper clay into a complex figurative silicon mold. i
then took it one step further, since silicon is easily able to handle heat,
i put the mold into my electric kiln at 200 degrees for a while to drive the
water out as the silicon doesn't absorb the water as plaster would, i used a
very soft clay to put into the mold as i felt a harder clay would move the
silicon as its a soft material. one point though you can't put the plaster
mother mold into the kiln.
norman
----- Original Message -----
From: "Craig Clark"
To:
Sent: Sunday, February 12, 2006 9:31 AM
Subject: Re: [CLAYART] Paperclay press moulding into silicon/latex moulds.
> Ama, go ahead and do what your friend has suggested. I have done
> half torso's and other castings with undercut problems using flexible
> rubber molds. They work very well. The only draw back is the mold
> material is much more expensive than plaster and you will also incur the
> additional cost of plaster bandages to back up and "stiffen" your
> flexible mother mold.
> To keep the clay from sticking just really coat the rubber with a
> good oil soap or vaseline. After you are sure that the clay you have
> pressed into your mold has set toward a soft leather state pull the
> rubber. From the look of your piece you shouldn't have much of a problem.
> Hope this helps
> Craig Dunn Clark
> 619 East 11 1/2 St.
> Houston, Texas 77008
> (713)861-2083
> mudman@hal-pc.org
>
> Ama Menec wrote:
>
> >Dear Clayarters,
> >
> >I'd love any feedback from anyone who press moulds clay, or paperclay,
into
> >something other than plaster, particularly on a larger scale. I'm just
> >finishing making a large and complex piece. Here's the link so you can
see
> >what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should point
> >out it's the bottom view of the sculpture, not of Ama Menec!) and it's
> >useful as it shows 2 hands, 2 feet, (all those little digits), and quite
a
> >lot of undercuts. I normally press mould into very hard plaster such as
> >Herculite or Prestia Creation, and I had resigned myself to casting this
as
> >a 5 piece press mould. I'd worked out the seam lines, (top section and 4
> >side panels), but still wobbling about how to arrange the order of
> >assembly/disassembly, when a chance remark from another sculptor friend
> >brought up another possibility I hadn't considered.
> >
> >She press moulds paperclay into small latex moulds and says the paperclay
> >doesn't stick like plain clay would. The items she casts are things such
as
> >bonio biscuits and MacDonald's cartons, I haven't seen anything bigger
than
> >that, and they are supported in turn by a plaster jacket mother mould.
Now I
> >have used rubber moulds with plaster mother moulds in the past when I
used
> >to cast in concrete, but I have never seen anyone using clay this way, or
on
> >a big scale. What I'm curious about is whether a large complex piece
would
> >work just as well this way, if it takes considerably longer to dry to the
> >point you can take it out, and whether you could make a facing of
paperclay
> >to be in contact with the latex or silicon mould and finish the rest of
the
> >press-moulding using ordinary clay.....
> >
> >I'd love to hear of anyone who has tried this or seen it done. Many
thanks,
> >
> >Ama, Totnes, Devon, UK.
> >
>
>___________________________________________________________________________
___
> >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.
> >
> >
> >
>
>
____________________________________________________________________________
__
> 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.
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.375 / Virus Database: 267.15.6/257 - Release Date: 2/10/2006
>
>
--
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Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.15.6/257 - Release Date: 2/10/2006
Ama Menec on sun 12 feb 06
Wow, the responses so far are fascinating! Debbie, can you tell me what RTV
and FMG stand for? Norman, I hadn't considered heating up the clay inside
the mould, that's amazing! This sculpture is 24" by 20", height somewhere
around 16", (something like that), by the way.
I've used hot melt rubber and also cold-cure rubber moulds in the
past...with cold cure rubber mix two very viscous materials together, stir
well and pour it in, make the mother mould from plaster afterwards. I've
never used silicone myself and had forgotten its heat withstanding
properties. I'm assuming with silicone I'd have to cover the sculpture in
clay to form a smooth non-undercut surface, build onto it the mother mould
making vents to add the silicone into, and let the air out of. Take off the
mother mould and the surface clay, and then replace the mother mould sealed
down well, and then pour in the liquid silicone? Are there any other ways?
Also, would pouring hot melt rubber over the original be easier and cheaper,
and then make the mother mould?
I'm intrigued about the use of spray foam....could this withstand being
used to make the mother mould itself and so no need to use plaster at all!??
What a happy thought!! I know this isn't what you meant Debbie, but it got
me thinking....it could be strong, lightweight, easy to handle and no chance
of plaster contamination....oh what joy! And if you dropped it, it would
bounce!!
Craig, would using Vaseline or oil soap, (not sure what that is exactly),
damage certain rubbers over time? And would using them interfere with the
working qualities of the clay if any adjustments were to be made to the
piece after it had been press moulded? I'm wondering now if it would work if
I poured hot melt rubber, (it's cheap, I can get it locally, it's viscous
and doesn't flow so fast that it runs everywhere, and scraps can be
re-used), over the whole piece until all the under cuts were gone, then when
it's set and cold, spray on some builders expandable foam for the mother
mould, smoothing over the top to make a flat base for the mould to rest on
when I turn it over? Any one tried this? Ocht, if that works I'd be
ecstatic! What do you think?
Ama, Totnes, Devon, UK.
----- Original Message -----
From: "Ama Menec"
To:
Sent: Sunday, February 12, 2006 12:21 PM
Subject: Paperclay press moulding into silicon/latex moulds.
> Dear Clayarters,
>
> I'd love any feedback from anyone who press moulds clay, or paperclay,
into
> something other than plaster, particularly on a larger scale. I'm just
> finishing making a large and complex piece. Here's the link so you can see
> what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should point
> out it's the bottom view of the sculpture, not of Ama Menec!) and it's
> useful as it shows 2 hands, 2 feet, (all those little digits), and quite a
> lot of undercuts. I normally press mould into very hard plaster such as
> Herculite or Prestia Creation, and I had resigned myself to casting this
as
> a 5 piece press mould. I'd worked out the seam lines, (top section and 4
> side panels), but still wobbling about how to arrange the order of
> assembly/disassembly, when a chance remark from another sculptor friend
> brought up another possibility I hadn't considered.
>
> She press moulds paperclay into small latex moulds and says the paperclay
> doesn't stick like plain clay would. The items she casts are things such
as
> bonio biscuits and MacDonald's cartons, I haven't seen anything bigger
than
> that, and they are supported in turn by a plaster jacket mother mould. Now
I
> have used rubber moulds with plaster mother moulds in the past when I used
> to cast in concrete, but I have never seen anyone using clay this way, or
on
> a big scale. What I'm curious about is whether a large complex piece would
> work just as well this way, if it takes considerably longer to dry to the
> point you can take it out, and whether you could make a facing of
paperclay
> to be in contact with the latex or silicon mould and finish the rest of
the
> press-moulding using ordinary clay.....
>
> I'd love to hear of anyone who has tried this or seen it done. Many
thanks,
>
> Ama, Totnes, Devon, UK.
>
>
____________________________________________________________________________
__
> 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.
Norman Aufrichtig on sun 12 feb 06
not at all,real easy to make the silicon mold, silicon can be made to be
brushable. you would only need a thin skin of it, and then there are some
nice materials that you can use to make the mother mold from that are very
light and not to expensive, but i don't think they would do that well with
heat. i was thinking about that to and i think especially with the kind of
sculpture that you are making (the whole bottom is open and a great place to
apply heat to the clay from with small heaters or heat lamps, just some
thoughts. i haven't worked with silicon for a few years so i don't remember
the names of the stuff you will need but the stuff is buried in my studio
and i can find it, or at least give you a address in the usa. right now am
busy getting ready for a show and don't have the time.
norman
----- Original Message -----
From: "Ama Menec"
To:
Sent: Sunday, February 12, 2006 1:50 PM
Subject: Re: [CLAYART] Paperclay press moulding into silicon/latex moulds.
> Wow, the responses so far are fascinating! Debbie, can you tell me what
RTV
> and FMG stand for? Norman, I hadn't considered heating up the clay inside
> the mould, that's amazing! This sculpture is 24" by 20", height somewhere
> around 16", (something like that), by the way.
>
> I've used hot melt rubber and also cold-cure rubber moulds in the
> past...with cold cure rubber mix two very viscous materials together, stir
> well and pour it in, make the mother mould from plaster afterwards. I've
> never used silicone myself and had forgotten its heat withstanding
> properties. I'm assuming with silicone I'd have to cover the sculpture in
> clay to form a smooth non-undercut surface, build onto it the mother mould
> making vents to add the silicone into, and let the air out of. Take off
the
> mother mould and the surface clay, and then replace the mother mould
sealed
> down well, and then pour in the liquid silicone? Are there any other ways?
> Also, would pouring hot melt rubber over the original be easier and
cheaper,
> and then make the mother mould?
>
> I'm intrigued about the use of spray foam....could this withstand being
> used to make the mother mould itself and so no need to use plaster at
all!??
> What a happy thought!! I know this isn't what you meant Debbie, but it got
> me thinking....it could be strong, lightweight, easy to handle and no
chance
> of plaster contamination....oh what joy! And if you dropped it, it would
> bounce!!
>
> Craig, would using Vaseline or oil soap, (not sure what that is exactly),
> damage certain rubbers over time? And would using them interfere with the
> working qualities of the clay if any adjustments were to be made to the
> piece after it had been press moulded? I'm wondering now if it would work
if
> I poured hot melt rubber, (it's cheap, I can get it locally, it's viscous
> and doesn't flow so fast that it runs everywhere, and scraps can be
> re-used), over the whole piece until all the under cuts were gone, then
when
> it's set and cold, spray on some builders expandable foam for the mother
> mould, smoothing over the top to make a flat base for the mould to rest on
> when I turn it over? Any one tried this? Ocht, if that works I'd be
> ecstatic! What do you think?
>
> Ama, Totnes, Devon, UK.
>
>
> ----- Original Message -----
> From: "Ama Menec"
> To:
> Sent: Sunday, February 12, 2006 12:21 PM
> Subject: Paperclay press moulding into silicon/latex moulds.
>
>
> > Dear Clayarters,
> >
> > I'd love any feedback from anyone who press moulds clay, or paperclay,
> into
> > something other than plaster, particularly on a larger scale. I'm just
> > finishing making a large and complex piece. Here's the link so you can
see
> > what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should
point
> > out it's the bottom view of the sculpture, not of Ama Menec!) and it's
> > useful as it shows 2 hands, 2 feet, (all those little digits), and quite
a
> > lot of undercuts. I normally press mould into very hard plaster such as
> > Herculite or Prestia Creation, and I had resigned myself to casting this
> as
> > a 5 piece press mould. I'd worked out the seam lines, (top section and 4
> > side panels), but still wobbling about how to arrange the order of
> > assembly/disassembly, when a chance remark from another sculptor friend
> > brought up another possibility I hadn't considered.
> >
> > She press moulds paperclay into small latex moulds and says the
paperclay
> > doesn't stick like plain clay would. The items she casts are things such
> as
> > bonio biscuits and MacDonald's cartons, I haven't seen anything bigger
> than
> > that, and they are supported in turn by a plaster jacket mother mould.
Now
> I
> > have used rubber moulds with plaster mother moulds in the past when I
used
> > to cast in concrete, but I have never seen anyone using clay this way,
or
> on
> > a big scale. What I'm curious about is whether a large complex piece
would
> > work just as well this way, if it takes considerably longer to dry to
the
> > point you can take it out, and whether you could make a facing of
> paperclay
> > to be in contact with the latex or silicon mould and finish the rest of
> the
> > press-moulding using ordinary clay.....
> >
> > I'd love to hear of anyone who has tried this or seen it done. Many
> thanks,
> >
> > Ama, Totnes, Devon, UK.
> >
> >
>
____________________________________________________________________________
> __
> > 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.
>
>
____________________________________________________________________________
__
> 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.
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.375 / Virus Database: 267.15.6/257 - Release Date: 2/10/2006
>
>
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.15.6/257 - Release Date: 2/10/2006
Norman Aufrichtig on sun 12 feb 06
i forgot to mention you need no separator with the silicon as long as you
let it get a little past leather hard.
norman
----- Original Message -----
From: "Ama Menec"
To:
Sent: Sunday, February 12, 2006 1:50 PM
Subject: Re: [CLAYART] Paperclay press moulding into silicon/latex moulds.
> Wow, the responses so far are fascinating! Debbie, can you tell me what
RTV
> and FMG stand for? Norman, I hadn't considered heating up the clay inside
> the mould, that's amazing! This sculpture is 24" by 20", height somewhere
> around 16", (something like that), by the way.
>
> I've used hot melt rubber and also cold-cure rubber moulds in the
> past...with cold cure rubber mix two very viscous materials together, stir
> well and pour it in, make the mother mould from plaster afterwards. I've
> never used silicone myself and had forgotten its heat withstanding
> properties. I'm assuming with silicone I'd have to cover the sculpture in
> clay to form a smooth non-undercut surface, build onto it the mother mould
> making vents to add the silicone into, and let the air out of. Take off
the
> mother mould and the surface clay, and then replace the mother mould
sealed
> down well, and then pour in the liquid silicone? Are there any other ways?
> Also, would pouring hot melt rubber over the original be easier and
cheaper,
> and then make the mother mould?
>
> I'm intrigued about the use of spray foam....could this withstand being
> used to make the mother mould itself and so no need to use plaster at
all!??
> What a happy thought!! I know this isn't what you meant Debbie, but it got
> me thinking....it could be strong, lightweight, easy to handle and no
chance
> of plaster contamination....oh what joy! And if you dropped it, it would
> bounce!!
>
> Craig, would using Vaseline or oil soap, (not sure what that is exactly),
> damage certain rubbers over time? And would using them interfere with the
> working qualities of the clay if any adjustments were to be made to the
> piece after it had been press moulded? I'm wondering now if it would work
if
> I poured hot melt rubber, (it's cheap, I can get it locally, it's viscous
> and doesn't flow so fast that it runs everywhere, and scraps can be
> re-used), over the whole piece until all the under cuts were gone, then
when
> it's set and cold, spray on some builders expandable foam for the mother
> mould, smoothing over the top to make a flat base for the mould to rest on
> when I turn it over? Any one tried this? Ocht, if that works I'd be
> ecstatic! What do you think?
>
> Ama, Totnes, Devon, UK.
>
>
> ----- Original Message -----
> From: "Ama Menec"
> To:
> Sent: Sunday, February 12, 2006 12:21 PM
> Subject: Paperclay press moulding into silicon/latex moulds.
>
>
> > Dear Clayarters,
> >
> > I'd love any feedback from anyone who press moulds clay, or paperclay,
> into
> > something other than plaster, particularly on a larger scale. I'm just
> > finishing making a large and complex piece. Here's the link so you can
see
> > what I mean: http://www.amamenec.co.uk/Bottom_view.jpg . (I should
point
> > out it's the bottom view of the sculpture, not of Ama Menec!) and it's
> > useful as it shows 2 hands, 2 feet, (all those little digits), and quite
a
> > lot of undercuts. I normally press mould into very hard plaster such as
> > Herculite or Prestia Creation, and I had resigned myself to casting this
> as
> > a 5 piece press mould. I'd worked out the seam lines, (top section and 4
> > side panels), but still wobbling about how to arrange the order of
> > assembly/disassembly, when a chance remark from another sculptor friend
> > brought up another possibility I hadn't considered.
> >
> > She press moulds paperclay into small latex moulds and says the
paperclay
> > doesn't stick like plain clay would. The items she casts are things such
> as
> > bonio biscuits and MacDonald's cartons, I haven't seen anything bigger
> than
> > that, and they are supported in turn by a plaster jacket mother mould.
Now
> I
> > have used rubber moulds with plaster mother moulds in the past when I
used
> > to cast in concrete, but I have never seen anyone using clay this way,
or
> on
> > a big scale. What I'm curious about is whether a large complex piece
would
> > work just as well this way, if it takes considerably longer to dry to
the
> > point you can take it out, and whether you could make a facing of
> paperclay
> > to be in contact with the latex or silicon mould and finish the rest of
> the
> > press-moulding using ordinary clay.....
> >
> > I'd love to hear of anyone who has tried this or seen it done. Many
> thanks,
> >
> > Ama, Totnes, Devon, UK.
> >
> >
>
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Debbie on sun 12 feb 06
Hi Ama,
Isn't brainstorming fun ! You've got me going now....the spay foam
insulation I use is too soft for a casing, you can easily crush it in your
hands but what if it where spayed over a substrate of say, something like
formed hardware cloth or chicken wire? Maybe worth a try....if it could be
found in a harder version.
FMG or Forton Modified Gypsum is a specialty gypsum that can be laminated
the same way that fiberglass can. I've got 5' long mold casings of this
material about 1/2" thick, very strong and light weight. It's available from
most sculpture supply stores. Follow directions carefully about mixing and
using.
RTV or Room Temperature Vulcanized rubber is a silicon mold material. These
vary tremendously in quality, my biggest concern is mold longevity. I want
molds that will last 20 or more years with out deterioration. Ama, what you
describe is called a French pour method of making a RTV mold but there is a
way that will use much less material. Brush a surface coat on your model
then subsequent layers of a thicker RTV up to the thickness you need. Some
kinds can be mixed up as thick as pea-nut butter for the later layers. After
that sets, make the casing over it. If the layers of RTV has left some
undercuts, these can be filled with little chunks of foam rubber (AKA the
corner of the sofa cushion) mixed with RTV and trowled into the area.
My molds are too large to force dry in a kiln (or should I say my kilns are
too small?) so I use a stand dryer, the type used to groom dogs. Thanks
everyone for the great ideas. I've been getting decent enough release with
out a lubricant (mainly because the RTV is quite thin and easily peels away)
but am excited about trying that. Best Wishes, Debbie
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Ama Menec
> Sent: Sunday, February 12, 2006 12:50 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Paperclay press moulding into silicon/latex moulds.
>
>
> Wow, the responses so far are fascinating! Debbie, can you tell
> me what RTV
> and FMG stand for? Norman, I hadn't considered heating up the clay inside
> the mould, that's amazing! This sculpture is 24" by 20", height somewhere
> around 16", (something like that), by the way.
>
> I've used hot melt rubber and also cold-cure rubber moulds in the
> past...with cold cure rubber mix two very viscous materials together, stir
> well and pour it in, make the mother mould from plaster afterwards. I've
> never used silicone myself and had forgotten its heat withstanding
> properties. I'm assuming with silicone I'd have to cover the sculpture in
> clay to form a smooth non-undercut surface, build onto it the mother mould
> making vents to add the silicone into, and let the air out of.
> Take off the
> mother mould and the surface clay, and then replace the mother
> mould sealed
> down well, and then pour in the liquid silicone? Are there any other ways?
> Also, would pouring hot melt rubber over the original be easier
> and cheaper,
> and then make the mother mould?
>
> I'm intrigued about the use of spray foam....could this withstand being
> used to make the mother mould itself and so no need to use
> plaster at all!??
> What a happy thought!! I know this isn't what you meant Debbie, but it got
> me thinking....it could be strong, lightweight, easy to handle
> and no chance
> of plaster contamination....oh what joy! And if you dropped it, it would
> bounce!!
>
> Craig, would using Vaseline or oil soap, (not sure what that is exactly),
> damage certain rubbers over time? And would using them interfere with the
> working qualities of the clay if any adjustments were to be made to the
> piece after it had been press moulded? I'm wondering now if it
> would work if
> I poured hot melt rubber, (it's cheap, I can get it locally, it's viscous
> and doesn't flow so fast that it runs everywhere, and scraps can be
> re-used), over the whole piece until all the under cuts were
> gone, then when
> it's set and cold, spray on some builders expandable foam for the mother
> mould, smoothing over the top to make a flat base for the mould to rest on
> when I turn it over? Any one tried this? Ocht, if that works I'd be
> ecstatic! What do you think?
>
> Ama, Totnes, Devon, UK.
>
David Martin Hershey on mon 13 feb 06
Hi Ama & All,
I've recently been pressing paper & regular clay into silicone.
These molds are as you describe- thin silicone supported
by a plaster jacket. Masks, about 14" x 9".
I originally made them to be cast in other materials,
but they work quite well with p.c.
My process is to press and shape the clay to about
1/2" thick, and run a fan on it for a while. When it can stand
on it's own, I invert the mold onto a ware board- hardibacker.
I then remove the plaster, and carefully peel the silicone
from the piece. Even undercuts are easy to remove.
Sometimes using compressed air can help the separation.
I don't use a release agent, but I have used corn starch
on silicone molds that I poured with paper slip.
Just a light brushing with a soft brush works well.
On the large figure, I like your idea to make a
French mold. It makes a more uniform thickness to
the rubber, and it is less likely to tear.
I would make the jacket (and maybe the rubber) in
sections, that bolt or screw together,
to make it easy to remove the work.
As far as rubber goes,
I find that silicone degrades after 30 to 50 castings
of almost any material, and tends to tear easily.
I am going to use a type of urethane on
future molds that I make specifically for p.c.
It resists being attacked by the sulfur in the clay,
and is more resilient than silicone.
Please be careful if you decide to use any foams.
Foaming agents are very toxic.
They killed poor Eva Hess...
I've decided not to use them anymore, but if you do-
be sure to wear a rated respirator, gloves, & safety glasses.
Work in a very well ventilated place, and be aware
that the toxic materials continue to outgas for days
after the foam has set.
BTW, thanks for the tip on the expanding urethane.
I plan to use it to scale up some pieces that I have
silicone molds for already. Did you ever try it?
Good luck on your casting! Keep us posted.
Best, DMH
Beautiful Hermosa Beach CA USA
where they just bulldozed my neighbor's
beautiful & expensive old home
to build two more dismal
Disney McMansions
Ama Menec on mon 13 feb 06
Thanks Norman and Debbie for that,
Debbie, do you have a website so we can see the scale of your work? Thanks
for explaining RTV, I'm assuming it comes ready mixed and it's the contact
with air that makes it set? I have ghastly memories of using cold-cure
rubber that comes in two drums that you measure and mix
together...everything, but everything ends up sticky. Forever. And its
ability to leak and piss everywhere is quite amazing. That was using the
French method. Awful. Silicon sounds a lot better, and I want long lasting
moulds. You guys have really cheered me up. Many thanks,
Ama, Totnes, Devon, UK.
Snail Scott on mon 13 feb 06
At 12:21 PM 2/12/2006 -0000, you wrote:
>...I
>have used rubber moulds with plaster mother moulds in the past when I used
>to cast in concrete, but I have never seen anyone using clay this way, or on
>a big scale...
Nan Smith uses rubber molds for life-size figural work.
-Snail>
Debbie on mon 13 feb 06
Hi Ama and all,
What I am doing is traditional figural. Sorry no web site photos but if you
picture a life sized horse's head appox 4' long you've got it.
Your ghastly memories are the same as some of mine of some not so good RTVs!
But after much experimentation I came to prefer Walco brand, 1065 and
VRM-65. It must be weighed accurately (gram scale) and mixed very
thoroughly, (transfer back & forth from weighing cup to another mixing cup
to get the stuff on the bottom evenly mixed in). The 1065 is pourable
(runny, good for the first thin brushed on coat), subsequent coats are a mix
of 1065 and the pea-nut butter like VRM-65 to a non-runny consistency and
painted on in layers. You can just blend the two to the desired consistency
then get the total weight then add the catalyst. Using pure VRM-65 is handy
for trowling onto upside down areas (such as under the horse's jaw). The
catalyst comes in two types, a green which is long setting and a blue which
is faster, but the actual time will depend on it's age and the
temperature/humidity (test). Keys to fit into the casing and to form seams
can be cut from poured sheets of RTV (which BTW sticks to glass with a
vengeance) and puttied onto the outer surface (stick pins can help here).
This RTV will set on wet clay with out a parting agent but the clay should
have no standing water on it. Brushing on a RTV mold has the advantage of
keeping it much thinner than would other wise be possible thus saving weight
and cost. I use the French pour method only for smaller pieces because it's
faster.
I chose this RTV because the molds last with out deterioration for a long,
long time and the material I buy is always of constant quality and
freshness. But I haven't tried them all and new ones are always being
offered. No manufacturer can give a strait answer about longevity because
the reactivity of materials poured into it, amount of stretching when
demanding, climate and storage temp. all factor in. My molds are used only
for wax and occasionally clay. The oldest ones are about 15, but I know of
others 20+ yrs and still as good as the day they where made! No shrinking,
stinking, distorting, dissolving or brittleness, (yes, there are some
ghastly memories here!).
I just looked at the Walco site: http://www.walcomaterials.com/main.html and
noticed they have instructional material posted. Polytek also has a nice
booklet on mold making: http://www.polytek.com/
Hope this helps! Debbie
>
>
> Thanks Norman and Debbie for that,
>
> Debbie, do you have a website so we can see the scale of your work? Thanks
> for explaining RTV, I'm assuming it comes ready mixed and it's the contact
> with air that makes it set? I have ghastly memories of using cold-cure
> rubber that comes in two drums that you measure and mix
> together...everything, but everything ends up sticky. Forever. And its
> ability to leak and piss everywhere is quite amazing. That was using the
> French method. Awful. Silicon sounds a lot better, and I want long lasting
> moulds. You guys have really cheered me up. Many thanks,
>
> Ama, Totnes, Devon, UK.
>
Delores Taylor on tue 14 feb 06
I've used SynAir's 333 product which is good if you have undercuts.
From a wax model:
I get three Solo cups that are the 16 oz red/blue/yellow and three paint
sticks. Mark the cups and the sticks A,B,C. Stirring your product VERY
well is critical from pre-mixing to activation. Syn-Air is by volume not
weight which makes it a bit more forgiving. The Solo cups have a design
that has ridges and acts as markers to pour exactly the same into cup A from
you're a mix and exactly the same into your cup B. The paint sticks marked
A and B are for pre mix stirring and get put back on top of the
corresponding can. Paint stick C is for mixing when you place half the a
and b cup into the c cup. Mix like mad, then add the balance of a and b
cup, mix again then pour the contents of C back into A and stir again. Then
pour a into b and stir again. This insures you get all the product mixed
well and out of the a and b cup. If you have a 3D sculpture I use a print
coat of 333, let that get tacky and then use 333 TA which is a thixotropic
and will not slid off the sculpture. On the final layer I smooth out the
urethane so the mother mold doesn't hook up on a nook or cranny.
My studio isn't as warm as my house so sometimes I have to let the molds
cure where it's warmer or they don't set up. I have had a mold fail for two
reasons the bas relief pour was too thick and I didn't do it in batches so
air could dry the layers and allow the mold to dry uniformly. The other
problem I had with a mold not setting up is too cold of a temperature. If
you have a 3D figure I then use a mother mold to back up the urethane.
From a Clay Model:
Make sure your product will set up with water based clay or sulfer based
plasticene and use the appropriate product or seal your clay model so there
isn't a reaction with your mold material and it will not set up.
What is the French pour method?
I find that with Urethene I have to use a release before I pour more wax
into the mold. I've had luck with bas reliefs and urethane and it didn't
need a release but have not tried a 3D with slip so I would love to hear
from others regarding this.
I don't like laytex it's stinky, takes too long and doesn't hold up as well
as a urethane would. Silicon bas reliefs can use water and after a plaster
pour will come out without a commercial release agent being used. This is a
plus because the urethane release agents are stinky and have to be sprayed
outside for safety. This is a bit problematic when you live in a rainly
climate.
Keep me cc'd if this goes off list as there's always more to learn here.
Hope this doesn't duplicate info from the archives. I would think that if
you are molding from your original paper clay model you would have to seal
the paper with the appropriate sealant for the product or the rubber mold
would hang up on the paper clay. Also be careful of the moisture in clay as
that can be an issue with a mold not setting up. This is why my molds are
make from wax not clays of any kind.
-----Original Message-----
From: Centa Uhalde [mailto:vicenta@SONIC.NET]
Sent: Sunday, February 12, 2006 11:22 PM
Subject: Re: Paperclay press moulding into silicon/latex moulds.
Hi Ama and Debbie,
I work sculpturally, and have worked in paper clay but I'm sure I'm not
using it to it's best advantage, yet, and have used press molds for larger
pieces. I haven't used rubber though. Please include me in the discussion
if it goes off line.
Thanks,
Centa
Norman Aufrichtig on tue 14 feb 06
the following web site is where i used to get my mold stuff from, great
place lots of infomation, http://www.perma-flex.com/
norman
----- Original Message -----
From: "Debbie"
To:
Sent: Monday, February 13, 2006 9:37 AM
Subject: Re: [CLAYART] Paperclay press moulding into silicon/latex moulds.
> Hi Ama and all,
>
> What I am doing is traditional figural. Sorry no web site photos but if
you
> picture a life sized horse's head appox 4' long you've got it.
>
> Your ghastly memories are the same as some of mine of some not so good
RTVs!
> But after much experimentation I came to prefer Walco brand, 1065 and
> VRM-65. It must be weighed accurately (gram scale) and mixed very
> thoroughly, (transfer back & forth from weighing cup to another mixing cup
> to get the stuff on the bottom evenly mixed in). The 1065 is pourable
> (runny, good for the first thin brushed on coat), subsequent coats are a
mix
> of 1065 and the pea-nut butter like VRM-65 to a non-runny consistency and
> painted on in layers. You can just blend the two to the desired
consistency
> then get the total weight then add the catalyst. Using pure VRM-65 is
handy
> for trowling onto upside down areas (such as under the horse's jaw). The
> catalyst comes in two types, a green which is long setting and a blue
which
> is faster, but the actual time will depend on it's age and the
> temperature/humidity (test). Keys to fit into the casing and to form seams
> can be cut from poured sheets of RTV (which BTW sticks to glass with a
> vengeance) and puttied onto the outer surface (stick pins can help here).
>
> This RTV will set on wet clay with out a parting agent but the clay should
> have no standing water on it. Brushing on a RTV mold has the advantage of
> keeping it much thinner than would other wise be possible thus saving
weight
> and cost. I use the French pour method only for smaller pieces because
it's
> faster.
>
> I chose this RTV because the molds last with out deterioration for a long,
> long time and the material I buy is always of constant quality and
> freshness. But I haven't tried them all and new ones are always being
> offered. No manufacturer can give a strait answer about longevity because
> the reactivity of materials poured into it, amount of stretching when
> demanding, climate and storage temp. all factor in. My molds are used only
> for wax and occasionally clay. The oldest ones are about 15, but I know of
> others 20+ yrs and still as good as the day they where made! No shrinking,
> stinking, distorting, dissolving or brittleness, (yes, there are some
> ghastly memories here!).
>
> I just looked at the Walco site: http://www.walcomaterials.com/main.html
and
> noticed they have instructional material posted. Polytek also has a nice
> booklet on mold making: http://www.polytek.com/
> Hope this helps! Debbie
>
>
> >
> >
> > Thanks Norman and Debbie for that,
> >
> > Debbie, do you have a website so we can see the scale of your work?
Thanks
> > for explaining RTV, I'm assuming it comes ready mixed and it's the
contact
> > with air that makes it set? I have ghastly memories of using cold-cure
> > rubber that comes in two drums that you measure and mix
> > together...everything, but everything ends up sticky. Forever. And its
> > ability to leak and piss everywhere is quite amazing. That was using the
> > French method. Awful. Silicon sounds a lot better, and I want long
lasting
> > moulds. You guys have really cheered me up. Many thanks,
> >
> > Ama, Totnes, Devon, UK.
> >
>
>
____________________________________________________________________________
__
> 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.
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.375 / Virus Database: 267.15.6/258 - Release Date: 2/13/2006
>
>
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Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 267.15.7/259 - Release Date: 2/13/2006
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