Discussion:
EPS Foam Vs. Polyurthane Foam
(too old to reply)
GaryR52
2005-07-19 13:52:03 UTC
Permalink
I'm interested in trying my hand at carved foam as a core material for
fiberglass sculpture. I've been reading up on both EPS (expanded
polystyrene) and polyurethane foam and the benefits and drawbacks of both,
but I am having trouble deciding which to use, and when to use either.

I like the easier carvability of EPS, but, where using it with fiberglass is
concerned, it requires the intermediate step of coating the piece with some
type of barrier coat before glassing it, as the polyester resin dissolves
the foam, otherwise. That seems to be the only major drawback with EPS.
Polyurethane, on the other hand, doesn't have this problem, but it costs
more than EPS, I believe.

As for carvability, polyurethane is probably just as easy to work, depending
upon the density of the foam. Where that's concerned, since this is core
material for the sculpture itself, as opposed to a foam pattern for casting
in a more durable material, such as bronze, I think using a density of less
than, say, 8 lb. is probably asking for trouble, right? Of course, the
fiberglass shell, plus any gel coat I might add on top of that will add to
the overall strength of the piece, but even so, I wouldn't want to use
something like 2 lb. Styrofoam, especially if it's to be displayed outdoors.
Any thoughts or suggestions? Thanks.

Gary
Gary Waller
2005-07-20 03:55:54 UTC
Permalink
Post by GaryR52
I'm interested in trying my hand at carved foam as a core material for
fiberglass sculpture. I've been reading up on both EPS (expanded
polystyrene) and polyurethane foam and the benefits and drawbacks of both,
but I am having trouble deciding which to use, and when to use either.
I like the easier carvability of EPS, but, where using it with fiberglass is
concerned, it requires the intermediate step of coating the piece with some
type of barrier coat before glassing it, as the polyester resin dissolves
the foam, otherwise. That seems to be the only major drawback with EPS.
Polyurethane, on the other hand, doesn't have this problem, but it costs
more than EPS, I believe.
As for carvability, polyurethane is probably just as easy to work, depending
upon the density of the foam. Where that's concerned, since this is core
material for the sculpture itself, as opposed to a foam pattern for casting
in a more durable material, such as bronze, I think using a density of less
than, say, 8 lb. is probably asking for trouble, right? Of course, the
fiberglass shell, plus any gel coat I might add on top of that will add to
the overall strength of the piece, but even so, I wouldn't want to use
something like 2 lb. Styrofoam, especially if it's to be displayed outdoors.
Any thoughts or suggestions? Thanks.
Gary
This is not as an easy question as it may seem. I need to know the type
of sculpture you propose - is it highly detailed? is it highly polished?
how big is it?

Unless you are proposing some modernist, globular, piece - you are
probably concentrating too much on what goes between the armature (the
frame which holds everything steady) and the final finished surface -
the foam is merely the filler between and not worthy of too much mental
exuberance or expense.

There are a wide variety of techniques for working foam for commercial
work (movies, amusements, signage) but the "art' of foam carving has
never been considered a 'fine' art. There is just something about the
medium, even the 8 lb foam, which limits the work.

This is not the way artists seem to work. As an example, Henry Moore, in
his emerging artist stage, proposed to produce 35 pieces a year - this
is carved stone by the way. He hired an assistant to carve within 1/4
iinch, working from mostly drawings, and then Moore finished the piece.
As a prime artist, bidding on major monuments, etc., he did commission
large eps foam carvings, again from his drawings and direction, to help
'sell' his ideas and concepts - the final pieces in monumental stone or
bronze.

The only impressive trick I have learned is to take polyester shell
molds from pottters/water clay. Clay is the medium for expression. The
armature is the key for large work with many hundreds of pounds of wet
clay. Speed is also the key - if you piss about, the whole thing will
start to crack. From the polyester shell mold, you cast a polyester
model (reuse the armature (and the clay)) - now you have captured the
expressiveness of the clay, and can add infinite details, time and
polishing for the final stretch. This gives you the best of both worlds.

In general - I think to learn how to work clay will be far more
rewarding for you than learning to work foam.

Start small, ask some more question, go from there.

Gary in Vancouver
GaryR52
2005-07-20 20:48:13 UTC
Permalink
Well, Gary, I beg to differ about foam and fiberglass not being fine art. As
early as the fifties, it was used by fine artists and there are various
examples since. Robert Howard, a friend of Alexander Calder's, was one of
the first to do use the medium. Duane Hanson is another name that comes to
mind. I'd watch it with shoot-from-the-hip statements like that, if I were
you. There was a time when metal sculpture wasn't considered sculpture,
either. Now, everyone and his dog is doing metal sculpture.

As for the limitations of the medium, there are none, to speak of. It can be
sculpted more easily, in fact, than any other carving medium and, no, the
foam is NOT "merely filler" - it IS the armature, as well as the principle
form of the sculpture. Depending upon the density of the foam, it is quite
stable and sturdy enough to be used for outdoor sculpture and it has been
used that way many, many times. The outer shell material gives the piece
it's outward finished appearance, as well as adding protection and
reinforcement. Think of the fiberglass as an endoskeleton, of sorts.
Actually, the entire structure, both foam and fiberglass, is a symbiotic
structure. It requires no armature, either, as foam is very light weight and
capable of supporting many times it own weight, especially at higher
densities. 16 lb. polyurethane has a compressive strength in excess of 500
psi, a sheer strength in excess of 300 psi and a flexural strength of over
750 psi. You'd need a hammer to put a dent in it.

To answer your other questions, no, there is no fine detail, but that
wouldn't be a problem, as foam (again, depending upon the density) can be
carved to a remarkable level of detail. It can also be mold cast to assume
any level of detail. But, my sculpture is non-objective abstract sculpture,
so detail is a moot point. Most of the time, it will have a smooth surface
treatment and that's all a function of the shell material; i.e., the
fiberglass and/or gel coat. But the foam itself can be sanded very smooth,
also. Keep in mind, we're not talking about the large celled packing
styrofoam variety, here. This is fine celled dense foam especially made for
carving and sculpting. The closest example I can think of to the forms I'll
be creating would be the work of Richard Erdman
(http://www.sculpturesite.com/artists/Erdm.lasso). His style is very similar
to mine, though his medium is not.

I'm very familiar with Henry Moore's work and most of his large scale
carvings were done in plaster for bronze. Some of his earliest pieces were
stone, but most of his monumental works were done in plaster for bronze and
I don't believe he ever did anything in foam, though it's a possibility he
might have flirted with it at some point in the later years of his career
(the eighties).

Clay is A medium, not THE medium for expression. Having worked with it, I
know very well its strengths and its limitations. There are numerous
sculpture media and each has its own advantages and disadvantages. Clay is
not the medium I would prefer to use for the pieces I have in mind. It's too
slow a process and, unless its fired (and ceramic sculpture has a limited
market appeal, due to its fragility), it is just another modeling medium for
bronze casting. I much prefer plasticine if bronze is to be the final
material, as plasticine is reusable, doesn't dry out, requires no firing,
isn't breakable and won't crack. Plus, it has all the best qualities of
clay. Anyway, I can swing either way, but the subtractive process of carving
just feels more like sculpting to me. Besides, clay wouldn't cut it for
these forms and at any kind of real size. Foam, as I said, is
self-supporting at any size and can be very quickly sculpted.

Where casting is concerned, either the carved foam itself, or the completed
sculpture can be the pattern for a mold for bronze casting. It is also
possible to use bonded bronze (via Design Cast 66 as the bonding medium)
over foam, as well. There are many ways to finish a foam carving, fiberglass
being only one.

By the way, Gary, it might be a good idea not to assume complete ignorance
when you're answering someone's post. I've been sculpting for over twenty
years in a number of media. I asked about polystyrene vs. polyurethane only
because I'm trying to make up my mind which to use.

Having just today been informed of Design Cast 66
(http://www.design-cast.com/products/products.html), which is especially
intended for use as a shell material over foam, I'm now thinking I'll use
that instead of fiberglass, thus eliminating any concerns over the use of
EPS. In other words, I can use either EPS or polyurethane; it makes no
difference because, unlike polyester resin, DC-66 doesn't attack the foam.

Thanks for the reply, Gary. It's always good to have a "devil's advocate."
;)

Gary
--
Post by GaryR52
I'm interested in trying my hand at carved foam as a core material for
fiberglass sculpture. I've been reading up on both EPS (expanded
polystyrene) and polyurethane foam and the benefits and drawbacks of
both, but I am having trouble deciding which to use, and when to use
either.
I like the easier carvability of EPS, but, where using it with fiberglass
is concerned, it requires the intermediate step of coating the piece with
some type of barrier coat before glassing it, as the polyester resin
dissolves the foam, otherwise. That seems to be the only major drawback
with EPS. Polyurethane, on the other hand, doesn't have this problem, but
it costs more than EPS, I believe.
As for carvability, polyurethane is probably just as easy to work,
depending upon the density of the foam. Where that's concerned, since
this is core material for the sculpture itself, as opposed to a foam
pattern for casting in a more durable material, such as bronze, I think
using a density of less than, say, 8 lb. is probably asking for trouble,
right? Of course, the fiberglass shell, plus any gel coat I might add on
top of that will add to the overall strength of the piece, but even so, I
wouldn't want to use something like 2 lb. Styrofoam, especially if it's
to be displayed outdoors. Any thoughts or suggestions? Thanks.
Gary
This is not as an easy question as it may seem. I need to know the type of
sculpture you propose - is it highly detailed? is it highly polished? how
big is it?
Unless you are proposing some modernist, globular, piece - you are
probably concentrating too much on what goes between the armature (the
frame which holds everything steady) and the final finished surface - the
foam is merely the filler between and not worthy of too much mental
exuberance or expense.
There are a wide variety of techniques for working foam for commercial
work (movies, amusements, signage) but the "art' of foam carving has never
been considered a 'fine' art. There is just something about the medium,
even the 8 lb foam, which limits the work.
This is not the way artists seem to work. As an example, Henry Moore, in
his emerging artist stage, proposed to produce 35 pieces a year - this is
carved stone by the way. He hired an assistant to carve within 1/4 iinch,
working from mostly drawings, and then Moore finished the piece. As a
prime artist, bidding on major monuments, etc., he did commission large
eps foam carvings, again from his drawings and direction, to help 'sell'
his ideas and concepts - the final pieces in monumental stone or bronze.
The only impressive trick I have learned is to take polyester shell molds
from pottters/water clay. Clay is the medium for expression. The armature
is the key for large work with many hundreds of pounds of wet clay. Speed
is also the key - if you piss about, the whole thing will start to crack.
From the polyester shell mold, you cast a polyester model (reuse the
armature (and the clay)) - now you have captured the expressiveness of the
clay, and can add infinite details, time and polishing for the final
stretch. This gives you the best of both worlds.
In general - I think to learn how to work clay will be far more rewarding
for you than learning to work foam.
Start small, ask some more question, go from there.
Gary in Vancouver
Gary Waller
2005-07-20 21:42:50 UTC
Permalink
Post by GaryR52
. The closest example I can think of to the forms I'll
be creating would be the work of Richard Erdman
(http://www.sculpturesite.com/artists/Erdm.lasso). His style is very similar
to mine, though his medium is not.
Sorry Gary - you will not be able to create a single work similar to
Richard Erdmans site using foam - at least based on the available
sculpture section and the sizes indicated. Foam is too weak - even at
15 lb density ($40 plus a cubic foot?), even with resin coatings. Even
if you did create such works - you will be unable to get anywhere the
price you need (for the hours of work) compared to stone or metal. Has
Richard Erdman ever made a plastic piece ? doesn't look like it.
Post by GaryR52
slow a process and, unless its fired (and ceramic sculpture has a limited
market appeal, due to its fragility), it is just another modeling medium for
bronze casting.
Hmmm - I just indicated that there is a technique to turn wet clay into
fiberglass - went over your head apparently




I much prefer plasticine if bronze is to be the final
Post by GaryR52
material, as plasticine is reusable, doesn't dry out, requires no firing,
isn't breakable and won't crack. Plus, it has all the best qualities of
clay.
Have you priced out a 2,000 lb pallet of plastecine lately? Compare to a
pallet of water clay and a drum of resin.
Post by GaryR52
By the way, Gary, it might be a good idea not to assume complete ignorance
when you're answering someone's post. I've been sculpting for over twenty
years in a number of media. I asked about polystyrene vs. polyurethane only
because I'm trying to make up my mind which to use.
You are doing a good enough job proving my assumption so far. I have
carved thousand's of lbs of foam over the years. I was selling metal
dust/epoxy coated E.P.S. architectural elements over 14 years ago - it
looks like crap today. You should also be aware of fire code
requirements in public areas, guess you haven't got to that stage yet.
You should also learn about something called wind shear if you think you
can just throw a big chunkoplastic out on some rich guy's lawn. You will
also find out that UV destroys all plastics. So the only fine art market
you are left with is basements in private homes - go for it, every niche
needs someone.

.
GaryR52
2005-07-20 22:50:54 UTC
Permalink
Post by Gary Waller
Sorry Gary - you will not be able to create a single work similar to
Richard Erdmans site using foam - at least based on the available
sculpture section and the sizes indicated. Foam is too weak - even at 15
lb density ($40 plus a cubic foot?), even with resin coatings. Even if you
did create such works - you will be unable to get anywhere the price you
need (for the hours of work) compared to stone or metal. Has Richard
Erdman ever made a plastic piece ? doesn't look like it.
I don't expect to be able to charge as much for a fiberglass sculpture as
for stone or metal any more than I'd expect to charge as much for a ceramic
piece as for a bronze. So what? I didn't say I'm trying to do what Erdman is
doing in steel, I said his forms are the closest to mine that I'm aware of.
That was merely to illustrate for you the type of sculpture I'm talking
about, since that's what you asked me. As for the hours, it requires quite a
few more to carve stone than it does foam and marble isn't that cheap,
either. Direct metal sculpture may be faster, but, again, so what? You don't
choose a sculpture medium soley for its cost or the speed of its use. You
choose it for its expressive qualities and stone has far less of that than
foam does because of the structural limitations of stone. Even direct metal
has its limitations, as far as form goes.
Post by Gary Waller
Hmmm - I just indicated that there is a technique to turn wet clay into
fiberglass - went over your head apparently
You don't "turn wet clay into fiberglass." Fiberglass used to be a Dupont
tradename for glass fiber reinforced polyester resin and the name has become
synomymous with the product. By definition, glass cloth and clay would not
be called "fiberglass," but, perhaps, fiberglass reinforced clay. In any
case, it would be a really stupid choice of media for large sculpture, or
sculpture at any scale, as it has to be fired to become hard and you can't
fire clay with fiberglass in it without fusing the glass fibers, thus,
rendering them into globules of glass and creating air pockets in the clay
in the process. It might work as a sort of grog, in that sense, but it would
be a lot cheaper to use broken clay shards as grog, as well as a lot
smarter.
Post by Gary Waller
Have you priced out a 2,000 lb pallet of plastecine lately? Compare to a
pallet of water clay and a drum of resin.
You're assuming monumental scale, which isn't the case for me, but, even if
it were, water clay certainly wouldn't be my choice of materials. As for the
price of Roma Plastilina, it comes in 2 lb. blocks for between $4 and $6,
depending on who you buy from. The fact that it's almost infinitely reusable
makes it a bargain for doing maquettes for bronze casting. That must be why
it's the favored medium for doing so.
Post by Gary Waller
You are doing a good enough job proving my assumption so far. I have
carved thousand's of lbs of foam over the years. I was selling metal
dust/epoxy coated E.P.S. architectural elements over 14 years ago - it
looks like crap today. You should also be aware of fire code requirements
in public areas, guess you haven't got to that stage yet. You should also
learn about something called wind shear if you think you can just throw a
big chunkoplastic out on some rich guy's lawn. You will also find out that
UV destroys all plastics. So the only fine art market you are left with is
basements in private homes - go for it, every niche needs someone.
I don't care how many years you say you've sculpted foam, Gary, you don't
know what you're talking about. Like I said, 16 lb foam, especially
reinforced with fiberglass, is not only capable of withstanding great
compressive force, but windshear and torquing, as well. I work in the field
of architecture and have for nearly thirty years, so I know a bit about the
structural characteristics of various materials, including foam. What do you
think EIFS (Exterior Insulated Finish Systems) is? Ever heard of Dryvit?
Foam, all foam. It's being used to clad buildings with. Also, think of all
the outdoor signage made of carved foam. If it weren't weatherable, it
wouldn't be in use for such applications, yet, it IS in such use daily, all
over the world, and has been for years. Also, how light do you think a huge
block of foam is? You seem to be assuming the same properties as packing
styrofoam and, as I said, that's not the stuff I'm talking about. As for UV,
it isn't an issue at all because the foam itself isn't exposed to the
elements. It will be encased in a hard shell of either resin or Design Cast,
which is as hard as stone. If you'd ever carved a block of foam in your
life, you'd know that. Sorry, but if you choose to be confrontational to
people who ask a legitimate question, expect to get a confrontational reply.
If your arrogant and offensive way of dealing with others is de riguer on
this newsgroup I've got other things to do besides engage in a pissing match
with some hothead who doesn't know what he's talking about. Bye.

Gary
Gary Waller
2005-07-21 00:39:44 UTC
Permalink
Post by GaryR52
You don't
choose a sculpture medium soley for its cost or the speed of its use. You
choose it for its expressive qualities and stone has far less of that than
foam does because of the structural limitations of stone. Even direct metal
has its limitations, as far as form goes>
Ok - you think foam looks better than stone or metal - got it - goodbye.
Post by GaryR52
It might work as a sort of grog, in that sense, but it would
be a lot cheaper to use broken clay shards as grog, as well as a lot
smarter.
Ok - still way over you head - the clay is removed (and resused) from
the fiberglass shell - no use wasting more time - goodbye.
Post by GaryR52
The fact that it's almost infinitely reusable
makes it a bargain for doing maquettes for bronze casting. That must be why
it's the favored medium for doing so.
2000 lbs of clay isn't really that much - even as a skin over foam - 1
inch thick - thats 156 square feet. - thats a box 8 foot by 8 foot by
2.5 foot
Post by GaryR52
What do you
think EIFS (Exterior Insulated Finish Systems) is? Ever heard of Dryvit?
Foam, all foam. It's being used to clad buildings with. Also, think of all
the outdoor signage made of carved foam. If it weren't weatherable, it
wouldn't be in use for such applications, yet, it IS in such use daily, all
over the world, and has been for years.
Ah - sorry architectural guy - the use of EIFS is actually banned in
many areas of the United States, too many vapor barrier/mold claims.
Mold claims are now the number one house damage claim in the U.S.A.
Besides - this is not resin/plastic - this is concrete coated foam.
Resin would never be allowed for this type of application - it is too
expensive, it breaks down in the sun, a huge fire hazard, and huge
environmental toxin load.





It will be encased in a hard shell of either resin or Design Cast,
Post by GaryR52
which is as hard as stone. If you'd ever carved a block of foam in your
life, you'd know that.
Hard as stone huh - I believe Granite is about 7 on the Mohs scale -
what is the hardness of design cast (or its multiple PU variables -
about 1.5 MOH?). Maybe thats not fair - what is its compressive strength
- granite is up around 25,000 psi .


Looks like you've convinced yourself that you want to attempt some
abstract noodling in foam. Go ahead. Just don't ask anyone to accept
this as a serious art form. Even sandcastle carving, ice carving and
chain saw carving are more accepted than resin covered foam carving.
Sorry - thats just the way it is.
GaryR52
2005-07-21 04:34:09 UTC
Permalink
Post by Gary Waller
Ok - you think foam looks better than stone or metal - got it - goodbye.
Not what I said at all. I said EXPRESSIVE. Look it up. In stone, you're not
only confined to the size and shape of the stone, but by its grain, it's
porousity and the strength of the particular stone. One wrong move and you
can shatter the whole piece. No such limits to foam. You need a bigger
piece? Laminate some sheets together or buy a larger piece. Grain? What
grain? All of these factors place limits on what you can do with any given
stone.
Post by Gary Waller
Ok - still way over you head - the clay is removed (and resused) from the
fiberglass shell - no use wasting more time - goodbye.
Then you're talking about mold making, not sculpting.
Post by Gary Waller
2000 lbs of clay isn't really that much - even as a skin over foam - 1
inch thick - thats 156 square feet. - thats a box 8 foot by 8 foot by 2.5
foot
2000 lbs of clay is quite a lot, actually. So is 156 square feet. Again, I'm
not talking about monumental sculpture. Unless commissioned to do so, I
wouldn't be doing anything over about 48" in any direction, for the most
part. A 48" cube of foam isn't that costly, nor is the material to cover
what's left of it after I'm done carving it. But, in any case, it's my
project, my money, so what do you care about the cost of making my work?
Post by Gary Waller
Ah - sorry architectural guy - the use of EIFS is actually banned in many
areas of the United States, too many vapor barrier/mold claims. Mold
claims are now the number one house damage claim in the U.S.A. Besides -
this is not resin/plastic - this is concrete coated foam. Resin would
never be allowed for this type of application - it is too expensive, it
breaks down in the sun, a huge fire hazard, and huge environmental toxin
load.
Name one area it's banned in and cite the relevent legislation, please.
There is no vapor barrier/mold issue, either. It's used as exterior
cladding, not as an interior material, so such issues are irrelevent. No one
said anything at all about resin, either. You really don't know much about
this.
Post by Gary Waller
Hard as stone huh - I believe Granite is about 7 on the Mohs scale - what
is the hardness of design cast (or its multiple PU variables - about 1.5
MOH?). Maybe thats not fair - what is its compressive strength - granite
is up around 25,000 psi .
I don't happen to have the figures, but I could get them. Better yet, why
don't you ask the manufacturer yourself? You might learn something:
http://www.design-cast.com/index.php
Post by Gary Waller
Looks like you've convinced yourself that you want to attempt some
abstract noodling in foam. Go ahead. Just don't ask anyone to accept this
as a serious art form. Even sandcastle carving, ice carving and chain saw
carving are more accepted than resin covered foam carving. Sorry - thats
just the way it is.
It already IS an art form, jackass, and who asked YOU, anyway? Thanks for
all your "help."

Gary
Gary Waller
2005-07-21 16:06:03 UTC
Permalink
Post by GaryR52
Name one area it's banned in and cite the relevent legislation, please.
There is no vapor barrier/mold issue, either. It's used as exterior
cladding, not as an interior material, so such issues are irrelevent. No one
said anything at all about resin, either. You really don't know much about
this.
From an apprentice jackass to a professional dumbass:
North Carolina, Georgia
http://www.consumerreports.org/main/content/display_report.jsp?FOLDER%3C%3Efolder_id=372403&ASSORTMENT%3C%3East_id=333147
GaryR52
2005-07-21 18:49:55 UTC
Permalink
Well, asshole, it sounds like you've managed to find one article that talks
about one incidence of one couple's bad experience with one provider of EIFS
material. If that's the best you can come up with, try again. The fact is,
EIFS has been in use for years on all sorts of buildings, from residential
to commercial and no such problems have existed in most cases. I submit that
the contractor's application of the EIFS material may not have been
correctly installed, resulting in the water damage and mold. It is the
principle benefit of ANY EIFS material that it should and does provide
weather cladding. That is its function, dumbass.

Gary
Post by Gary Waller
Post by GaryR52
Name one area it's banned in and cite the relevent legislation, please.
There is no vapor barrier/mold issue, either. It's used as exterior
cladding, not as an interior material, so such issues are irrelevent. No
one said anything at all about resin, either. You really don't know much
about this.
North Carolina, Georgia
http://www.consumerreports.org/main/content/display_report.jsp?FOLDER%3C%3Efolder_id=372403&ASSORTMENT%3C%3East_id=333147
Paul Nuttall
2005-07-24 08:23:41 UTC
Permalink
Gary W, your comments about Henry Moore had me searching through my book
collection, where I found a great photo of Moore standing looking up at half
of the full-scale version of Mirror Knife Edge, made of polystyrene, and
comparing it with half of a working model. The photo is in a book called
With Henry Moore, and on the facing page he does a little rave on the
subject:: "I first used polystyrene in the early 1960s, when I was asked to
design the scenery for Mozart's opera Don Giovanni. Certain parts of the
scenery were made in polystyrene. From then on, I realised that it was going
to save a lot of time, energy and effort."

With a little more searching I found that he routinely made sculptures in
polystyrene, then had them cast in plaster so he could work the surface for
better detail. Then they were cast in wax, and finally bronze. Obviously
this is somewhat different to making the final product in polystyrene, but
interesting all the same.
Post by Gary Waller
This is not the way artists seem to work. As an example, Henry Moore, in
his emerging artist stage, proposed to produce 35 pieces a year - this
is carved stone by the way. He hired an assistant to carve within 1/4
iinch, working from mostly drawings, and then Moore finished the piece.
As a prime artist, bidding on major monuments, etc., he did commission
large eps foam carvings, again from his drawings and direction, to help
'sell' his ideas and concepts - the final pieces in monumental stone or
bronze.
GaryR52
2005-07-24 17:38:45 UTC
Permalink
Paul, I came across a photo of Moore working on another piece in foam, circa
the late sixties. While most of his original carvings were in plaster, as I
said before, it looks like Gary was correct that he did work in EPS at some
point, at least for some pieces. The piece I found was Large Spindle Piece
(1966/1974): http://www.tepapa.govt.nz/Henry_web/process.htm

Interestng that he cast wax patterns from these pieces before casting in
Bronze, though. There was some use of lost foam casting at least as late as
the seventies, and perhaps it was even used in the sixties by some, as well.
Apparently, there was some reason why he didn't do this. Maybe he just
wasn't aware it was possible?

By the way, sculpting in EPS for bronze is one route I'd also like to try,
in addition to using foam as a core material for fiberglass and other finish
shell material (such as Design Cast). The trouble is finding a foundry that
does lost foam casting, as not many do.

Gary R.
--
______________________________
"Things Remembered," my new CD!
http://www.cdbaby.com/cd/garyrea
Post by Paul Nuttall
Gary W, your comments about Henry Moore had me searching through my book
collection, where I found a great photo of Moore standing looking up at half
of the full-scale version of Mirror Knife Edge, made of polystyrene, and
comparing it with half of a working model. The photo is in a book called
With Henry Moore, and on the facing page he does a little rave on the
subject:: "I first used polystyrene in the early 1960s, when I was asked to
design the scenery for Mozart's opera Don Giovanni. Certain parts of the
scenery were made in polystyrene. From then on, I realised that it was going
to save a lot of time, energy and effort."
With a little more searching I found that he routinely made sculptures in
polystyrene, then had them cast in plaster so he could work the surface for
better detail. Then they were cast in wax, and finally bronze. Obviously
this is somewhat different to making the final product in polystyrene, but
interesting all the same.
Post by Gary Waller
This is not the way artists seem to work. As an example, Henry Moore, in
his emerging artist stage, proposed to produce 35 pieces a year - this
is carved stone by the way. He hired an assistant to carve within 1/4
iinch, working from mostly drawings, and then Moore finished the piece.
As a prime artist, bidding on major monuments, etc., he did commission
large eps foam carvings, again from his drawings and direction, to help
'sell' his ideas and concepts - the final pieces in monumental stone or
bronze.
s***@tfb.com
2005-07-24 19:50:12 UTC
Permalink
CAsting in lost EPS would require that the foam itself be only a few
millimeters thick, and at large scales like in Moore's work this is
untenable. eighth inch thick EPS is not structurally cohesive nor
strong enough to support its own weight at these sizes.
Picture large curving sheets of foam like a car windshield.

For Moore- it was much more facile to take simple plaster molds from
the foam model and then, at the foundry, they could literally use sheet
wax of contsant thickness laid into the open plaster molds to make the
wax parts.
This is a very direct, simple and accurate process for doing large
simple surfaces like Moore's

christopher
GaryR52
2005-07-24 20:39:29 UTC
Permalink
Post by s***@tfb.com
CAsting in lost EPS would require that the foam itself be only a few
millimeters thick, and at large scales like in Moore's work this is
untenable. eighth inch thick EPS is not structurally cohesive nor
strong enough to support its own weight at these sizes.
Picture large curving sheets of foam like a car windshield.
Right, but I'm not planning on monumental sizes; nothing larger than 36" or
48" at most, in fact. At that size, you could hollow out the foam, to an
extent, pack the cavity with sand and use a sand foundry to cast in
aluminum. Not as intrinsically valuable as bronze, I know, but it would
work. Seriously, though, if I'm going to do anything in foam, it'll probably
be core material for either fiberglass or a Design Cast shell.
Post by s***@tfb.com
For Moore- it was much more facile to take simple plaster molds from
the foam model and then, at the foundry, they could literally use sheet
wax of contsant thickness laid into the open plaster molds to make the
wax parts.
This is a very direct, simple and accurate process for doing large
simple surfaces like Moore's
Ah, I see. I was wondering how he went about the process.
Paul Nuttall
2005-07-26 09:14:06 UTC
Permalink
I gather at least part of the reason for the plaster step was because it was
then easier to add surface detail.

For very small pieces you can cast straight from solid polystyrene to bronze
or aluminium. . I've tried making solid pieces myself in both metals, but at
less than 12" and fairly thin the bronze is a good weight. I've also seen
someone make a solid life size head, which I could barely lift. The size
you're talking about would weigh rather a lot

I was interested to see where you found the link of him making the Large
Spindle Piece. Te Papa is the museum of New Zealand, in Wellington, where I
live. They had a huge Henry Moore exhibition there a couple of years back
with numerous large pieces shipped in from England.
Post by GaryR52
Post by s***@tfb.com
CAsting in lost EPS would require that the foam itself be only a few
millimeters thick, and at large scales like in Moore's work this is
untenable. eighth inch thick EPS is not structurally cohesive nor
strong enough to support its own weight at these sizes.
Picture large curving sheets of foam like a car windshield.
Right, but I'm not planning on monumental sizes; nothing larger than 36" or
48" at most, in fact. At that size, you could hollow out the foam, to an
extent, pack the cavity with sand and use a sand foundry to cast in
aluminum. Not as intrinsically valuable as bronze, I know, but it would
work. Seriously, though, if I'm going to do anything in foam, it'll probably
be core material for either fiberglass or a Design Cast shell.
GaryR52
2005-07-26 12:45:08 UTC
Permalink
Post by Paul Nuttall
I gather at least part of the reason for the plaster step was because it was
then easier to add surface detail.
You're probably right, Paul. Moore was very concerned with the surface and
always deliberately left his tool marks, as he believed in the artist
showing evidence of his own presence.
Post by Paul Nuttall
For very small pieces you can cast straight from solid polystyrene to bronze
or aluminium. . I've tried making solid pieces myself in both metals, but at
less than 12" and fairly thin the bronze is a good weight. I've also seen
someone make a solid life size head, which I could barely lift. The size
you're talking about would weigh rather a lot
Yep, that's what I've been thinking, too. At that size, or even a bit
larger, you can hollow out the foam, to an extent, to lighten the casting a
little, too. I wouldn't try it at 24" and up, though.
Post by Paul Nuttall
I was interested to see where you found the link of him making the Large
Spindle Piece. Te Papa is the museum of New Zealand, in Wellington, where I
live. They had a huge Henry Moore exhibition there a couple of years back
with numerous large pieces shipped in from England.
That was the first I had seen of that image, or that I'd heard of his using
EPS, for that matter. I have a huge book of Moore's works (Henry Moore:
Sculpture and Environment) and it only mentions his plasters for bronze.

Gary
GaryR52
2005-07-24 20:42:07 UTC
Permalink
P.S.: If not EPS, then polyurethane (as core material, not for lost foam
casting), which can be very dense and has greater structural strength than
EPS.

Gary
Dan S
2005-10-02 16:28:04 UTC
Permalink
Just saw a huge Moore in Wash DC. I really didn't care for it. But I was
unable to see it from far enough away (50 yds would probably have sufficed.)
Seems likely styro was the original material, but the surface looked
clay-ey.
Dan

----------
Post by Paul Nuttall
Gary W, your comments about Henry Moore had me searching through my book
collection, where I found a great photo of Moore standing looking up at half
of the full-scale version of Mirror Knife Edge, made of polystyrene, and
comparing it with half of a working model. The photo is in a book called
With Henry Moore, and on the facing page he does a little rave on the
subject:: "I first used polystyrene in the early 1960s, when I was asked to
design the scenery for Mozart's opera Don Giovanni. Certain parts of the
scenery were made in polystyrene. From then on, I realised that it was going
to save a lot of time, energy and effort."
With a little more searching I found that he routinely made sculptures in
polystyrene, then had them cast in plaster so he could work the surface for
better detail. Then they were cast in wax, and finally bronze. Obviously
this is somewhat different to making the final product in polystyrene, but
interesting all the same.
Post by Gary Waller
This is not the way artists seem to work. As an example, Henry Moore, in
his emerging artist stage, proposed to produce 35 pieces a year - this
is carved stone by the way. He hired an assistant to carve within 1/4
iinch, working from mostly drawings, and then Moore finished the piece.
As a prime artist, bidding on major monuments, etc., he did commission
large eps foam carvings, again from his drawings and direction, to help
'sell' his ideas and concepts - the final pieces in monumental stone or
bronze.
Henri
2005-07-21 01:09:38 UTC
Permalink
Gary,

check this site out

http://www.mardigrasworld.com/

They use foam,, and cover it with papier-mâché,, (fiberglass also based on
what I saw there a couple weeks ago). The tour is really neat,, all those
figures are made of foam.
Post by GaryR52
I'm interested in trying my hand at carved foam as a core material for
fiberglass sculpture. I've been reading up on both EPS (expanded
polystyrene) and polyurethane foam and the benefits and drawbacks of both,
but I am having trouble deciding which to use, and when to use either.
I like the easier carvability of EPS, but, where using it with fiberglass
is concerned, it requires the intermediate step of coating the piece with
some type of barrier coat before glassing it, as the polyester resin
dissolves the foam, otherwise. That seems to be the only major drawback
with EPS. Polyurethane, on the other hand, doesn't have this problem, but
it costs more than EPS, I believe.
As for carvability, polyurethane is probably just as easy to work,
depending upon the density of the foam. Where that's concerned, since this
is core material for the sculpture itself, as opposed to a foam pattern
for casting in a more durable material, such as bronze, I think using a
density of less than, say, 8 lb. is probably asking for trouble, right? Of
course, the fiberglass shell, plus any gel coat I might add on top of that
will add to the overall strength of the piece, but even so, I wouldn't
want to use something like 2 lb. Styrofoam, especially if it's to be
displayed outdoors. Any thoughts or suggestions? Thanks.
Gary
Gary Waller
2005-07-21 01:40:18 UTC
Permalink
Post by Henri
Gary,
check this site out
http://www.mardigrasworld.com/
They use foam,, and cover it with papier-mâché,, (fiberglass also based on
what I saw there a couple weeks ago). The tour is really neat,, all those
figures are made of foam.
I don't know which Gary you mean!

What I see is some state of the art scenery work - I have seen some of
this company's work at West Edmonton Mall. Look at this section of the
website
http://www.mardigrasworld.com/accolades.html
They mention the use of clay - it is the best way to do the more
complicated pieces. Don't forget that main reason they use foam, like
the movie and theatre world, is to keep the weight down.

Must have been a fun and interesting tour. I know many people in this
industry in Canada, United States and Mexico.

Gary in Vancouver
GaryR52
2005-07-21 04:41:10 UTC
Permalink
Obviously, he meant me, Gary, since I started the thread, remember? You're
no longer the only one named Gary around here. ;)

Gary
Post by Gary Waller
Post by Henri
Gary,
check this site out
http://www.mardigrasworld.com/
They use foam,, and cover it with papier-mâché,, (fiberglass also based
on what I saw there a couple weeks ago). The tour is really neat,, all
those figures are made of foam.
I don't know which Gary you mean!
What I see is some state of the art scenery work - I have seen some of
this company's work at West Edmonton Mall. Look at this section of the
website
http://www.mardigrasworld.com/accolades.html
They mention the use of clay - it is the best way to do the more
complicated pieces. Don't forget that main reason they use foam, like the
movie and theatre world, is to keep the weight down.
Must have been a fun and interesting tour. I know many people in this
industry in Canada, United States and Mexico.
Gary in Vancouver
GaryR52
2005-07-21 04:37:26 UTC
Permalink
Thanks, Henri. Nice stuff, though not what I'm into at all. I'm interested
in the fine art applications. Papier mache wouldn't be a suitable skin for
my use.

Gary
Post by Henri
Gary,
check this site out
http://www.mardigrasworld.com/
They use foam,, and cover it with papier-mâché,, (fiberglass also based on
what I saw there a couple weeks ago). The tour is really neat,, all those
figures are made of foam.
Post by GaryR52
I'm interested in trying my hand at carved foam as a core material for
fiberglass sculpture. I've been reading up on both EPS (expanded
polystyrene) and polyurethane foam and the benefits and drawbacks of
both, but I am having trouble deciding which to use, and when to use
either.
I like the easier carvability of EPS, but, where using it with fiberglass
is concerned, it requires the intermediate step of coating the piece with
some type of barrier coat before glassing it, as the polyester resin
dissolves the foam, otherwise. That seems to be the only major drawback
with EPS. Polyurethane, on the other hand, doesn't have this problem, but
it costs more than EPS, I believe.
As for carvability, polyurethane is probably just as easy to work,
depending upon the density of the foam. Where that's concerned, since
this is core material for the sculpture itself, as opposed to a foam
pattern for casting in a more durable material, such as bronze, I think
using a density of less than, say, 8 lb. is probably asking for trouble,
right? Of course, the fiberglass shell, plus any gel coat I might add on
top of that will add to the overall strength of the piece, but even so, I
wouldn't want to use something like 2 lb. Styrofoam, especially if it's
to be displayed outdoors. Any thoughts or suggestions? Thanks.
Gary
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