polystrene block?

[ara]

anybody body know how to make (or where to get at a reasonable price) a block of polystrene?

need one about 12" sq to carve into.


cheers

ara

[PTsideshow]

First off poly styrene isn't good for carving.
Use this high impact styrene sheet for models, prototypes, signs, displays, enclosures, and more. It can be drilled, threaded, sawed, sheared, punched and machined.
The above is straight form a web site page. not much good for carving. The other thing is thickest I could find among a couple of US sources is .187 4'x8' sheets at $84.44 So you would need 3 sheets you would then end up with
About 11.968 high 12 " on a side for $253.32 with out cutting or fabrication charges.
You may want to look around the UK plastic suppliers for a catalog or web site and start over.

[ara]

thanks for the input and the website

goodness it is expensive!


i dont know if i can use the modelling strene stuff because its going to be a direct burn out in an iron pour and i believe that other stuff is full of cyanide and other kinds of nasties.

ordinary poly is not great to breathe in either of course but it doesnt make you keel over straight away!

hmm maybe i should think about making a piece sand mould..


cheers


ara

[sculptor]

15+ years ago, i had an @3'x3'x8' block of green foam(the kind florists use for flower arrangements) for carving---think maybe spent $200-$300 at that time
probably 3x that price today

really excellent carving material, but left so much stray stuff in the studio that it got into my clay and turned into a real pain

in the long run, i found it easier to work the clay and make a mold and copy

[Merlion]

My experience is limited. The green foam block used for flower arrangement is of course very easy to cut and carve. But it cannot keep its shape and crumbles easily.

The beaded polystyrene block can also be cut and carve easily, and is more solid. But being formed from beads, the carving cannot be in detail.

Styroform by Dow Chemical is the best for cutting and carving, but it is more expensive.

I understand when burnt polystrene releases toxic fume.

[PTsideshow]

I thought thats maybe what you were referring to but waited to see your answer. The foam they use for lost foam casting is a type of closed cell foam. Meaning that the cells of air share a wall enclosing the air. It is available in different densities per pound of material. That is what is CNC ed into dies in the the tool and die world. It is even more expensive that the green foam mention.
There is a company that sells some more use in the routering and making of signs. Still expensive, but not as much as the real stuff for die casting.
The old standby here in the US is the building insulation foam, pink, blue or yellow, closed cell expanded insulation board. Comes in 4'x8' sheets in 1/2"to2" thickness. Way cheaper 1" was about $15.00/sheet last month when I was putting it under the siding on the house.
Carves easy by hand can be laminated to any thickness ect.
If you glue it to itself make sure you use the appropriate glue.
as some eat it away.
Here are some web sites you might find of interest.
The best site for small scale home foam casting
Look for the on line videos, this is an industrial supplier
This is their hobby small use division
Finally the grandady of all backyard casting sites, and the use of foam
This is one type of precision board used in sign industry

The enclosed are two pictures form 12 or better years ago of a parade two person wearing/walking sub sandwich I made from insulation foam, upholstery foam spackle ect.
One person in each section hang off shoulder straps, and so they could walking them with out betting their shins to death

[ara]

that green stuff burns out?? excellent i might try that.. i can carve it outside to keep the mess to a minimum (thanks for the heads up sculptor)

to make sure we are thinking of the same stuff here...a soft crumbly green foam stuff that you push flower stems into, i believe its name over here is 'oasis'?

cheers for the links PT, some interesting stuff there.

off to the florist i go...


just quickly, what do we think is the best way to stick blocks of the green stuff together? ordinary pva or something a bit stronger?


cheers

ara

[PTsideshow]

You have to use something that will not melt the foam. They have stuff at the home builders centers

[Daniel]

3M makes a spray glue called "FoamFast 74" that works pretty well for gluing foam blocks together. I've never tried using it in a lost foam casting, so I don't know if it would vaporize quickly enough.

[obseq]

Be sure to test any adhesives on foam before committing to using it on your work-- Just about every conceivable glue/adhesive I experimented with yielded some degree of corrosion/pitting in the foam. The burnout isn't much of a concern as is the pitting that can appear in the final cast.

Originally Posted by Daniel

3M makes a spray glue called "FoamFast 74" that works pretty well for gluing foam blocks together. I've never tried using it in a lost foam casting, so I don't know if it would vaporize quickly enough.

[ara]

Daniel, i've just been to the hardware store and i didnt find anything called 'foamfast 74', i think its an american product, is it specifically for sculpture or something connected to industry/domestic use?
i think i'll just try pva, hopefully that should burn out without too much trouble.

i will report back when the burnout has been done and tell yall how it went (burnout will be end of sept so a while to wait!)


cheers
ara

[Daniel]

I haven't seen it in many hardware stores, either. I've always bought it from industrial supply places like McMaster-Carr. Not sure where you would get it in the UK. Like Obseq mentioned, though, you should always test on a small scrap before spraying it all over your piece, just to make sure that it is compatible with your particular foam.
best of luck.
D

[foamcutter]

Ara, a little late with the post but builders merchants probably wont have it in block form, hobby shops probably wont stock it as it is a low value product and takes up a lot of space.

graham sweet is based in Cardiff they might have blocks available. If that goes nowhere I could post a block over, it wouldn't be that expensive as foam is so light.

[the3rd]

even later still.

i use the bead foam and a sawzall, razor knifes (box cutters) for the detail. others have said to use the green foam but this stuff is pretty inexpensive. i dont have many pictures but we would get big blocks 4x4x8 for like $200-$300 bucks.

Atlas Foam

i would also use this two part foam mix ??? handi-foam i think. i got it from grainger that was like $300 a box. i would build a wood frame, then spray a coat around it. it has a high expansion rate. i would also use that as a glue to marry sheets together. this product will set-up and be ready to carve in minutes.

this was a small block of bead foam with Foam Coat


this is handi-foam with wood skeleton with a concrete skim coat



this is a mix of both, most is handi foam, the structual part is 3''x4x8 bead foam sheets and Foam Coat and paint




i liked how this turned out. how the foam looks like stone in the close-ups

the selling point for me is the cost and time in which it takes to get these shapes. ive done human forms, 4 10' tiki statues, bobsleds. i have friends that will bulk the shape in foam, paint a thin wax layer, then put clay over that, then mold and cast bronze. it saves so much clay, which is also recycled and save due to the wax layer. hope this helps and its not to late

-T

[rhendriks]

Thanks for showing your foam work.

Rob
See My Foam Reliefs

[foamcutter]

Nice work 3rd. Love the textures.

[the3rd]

thanks!

[hotwired]

Shipping large quantities of EPS foam can be very expensive. If you need big blocks or large quantities ($250 or more) of foam this company has over 80 locations throughout the U.S.


http://hotwirefoamfactory.com/custom...foamblocks.htm

If you look closely at the picture below you will see how artist Colleen Black made a full 3D "Hanging Dog Sculpture" (that created quite a stir with her neighbors and led to a police investigation!) using 2" foam slices.
For the whole story:
http://hotwirefoamfactory.com/custom...art_cblack.htm

[obseq]

Hotwired,

As described in my message to you, we do not allow any form of advertising from suppliers or service bureaus-- Please stop posting links to your company!

[ara]

hello everyone wow its been a while since i checked this thread.
Thank you for all the links and information. That foam with 'concrete skim' (which is what?) sculpture with the figures looks good.

I didn't use the oasis in the end, i tried burning it and it went black but didn't disintegrate, in fact the heat went inwards and i nearly set the place on fire because it was still burning on the inside and i didn't realise!

I used wax for the pattern in the end, and made a piece sand mould. Came out pretty good

I found a few blocks of regular poly in skips around my neighbour hood, seems like you just have to be lucky with the stuff

Cheers for the help,

ara

[foamcutter]

Ara, you could also try gm polystyrene from Hengoed, If you don't have any luck finding foam locally.