Questions on Clay and Sculpting

[CSMacLaren]

I've not touched clay since I was a kid. I have some good experience with epoxy putties, sanding, filing and shaping. I wanted to scratch-build a helmet and figured that clay would be inexpensive. Now, normally I'm used to stuff like AquaMend where it cures in about 12-20 minutes and I can build a bit at a time. I primarily rely on a handheld electric sander and a variety of Nicholson files and detailing files.

My main question with clay is that do people allow it to dry and then add on parts they need? I want to do this a bit at a time rather than to attempt the whole shebang all at once. Let me know if that approach is wrong or not.

What I find is that when I add to clay, it peels and cracks.

Unless I slip clay into the cracks to "glue" them together, parts that I add might break off. My goal was to approximate a skullcap first, then sand it down to shape.

Now, I'm approaching clay with an epoxy-putty mentality, so let me know I'm off base here with my approach.

Thanks.

 

[kitfreak]

It looks like you are using water clay, you might try using oil based clay instead. It stays soft and a lot more workable, water clay needs to stay moist while working it and is harder to dry if building large solid objects.

 

[Roughneckone]

Have a word with the folks over at the FX Lab, I'm sure they will be delighted to help you out.

Roughneckone

 

[CSMacLaren]

Kitfreak,

Yes, I'm using Stonex, which is a self-hardening clay that comes moist, and you could indeed water it down.

But an oil based clay isn't going to harden, is it, unless you bake it?

The reason why I opeted for an air-drying clay is so that once hardened it can support the structure of new unhardened additions.

Roughneckone,

Thanks for the link. I'll check it out.

 

[steveo]

It will be very hard to get wet clay to stick to dry clay once it dries. The clay also shrinks as it dries which also leads to cracking unless you let it dry slowly. Hope this helps ya.

 

[CSMacLaren]

Thanks, guys. I've come to the conclusion I'm using the wrong product, and what I need is an epoxy clay that mixes in two parts, and that behaves like the material I'm already used to. I'm now eyeballing this:

http://www.avesstudio.com/Products/Apoxie_...xie_sculpt.html

and

http://www.avesstudio.com/html/fixit_sculpt.html

 

[rollerboi]

You might look into building an armature to support the weights of whatever parts you have planned for the sculpture, and then add oil-based clay over it.

I get the impression that most folks here sculpt with oil-based clays and cast a mold, rather than having an actual hard clay sculpture.

 

[MaddChinaMan]

<div class='quotetop'>QUOTE(rollerboi @ Apr 7 2007, 04:39 PM) [snapback]1457534[/snapback]</div>

You might look into building an armature to support the weights of whatever parts you have planned for the sculpture, and then add oil-based clay over it.

I get the impression that most folks here sculpt with oil-based clays and cast a mold, rather than having an actual hard clay sculpture.
[/b]

Do any of you know a easy way of casting a clay sculpture at home?

 

[GeneralMayhem]

<div class='quotetop'>QUOTE(MaddChinaMan @ Apr 7 2007, 10:45 PM) [snapback]1457688[/snapback]</div>

Do any of you know a easy way of casting a clay sculpture at home?
[/b]

Freeman Supply hosts some wonderful Video Tutorials on casting that apply to this type of work.


~ GM

 

[DaddyfromNaboo]

Another possibly useful resource :

http://www.sculpture.net/

Michael

 

[weaselflinger]

In my experiance, oil based clay (plasticene) works well for projects that aren't much bigger than helmet size and /or are going to be sculpted over a long period of time. There are many different plasticenes available with a variety of ingredients and characteristics and picking one is determined by budget, preference, as well as what you plan to do with the sculpture once it's finished. Some plasticenes contain sulphur for example and won't work if you plan to use silicone for the mold.

Aves apoxie sculpt works best for repair or small scale figures. I can't imagine what a huge pain in the butt it would be to sculpt a 1/1 helmet out of that stuff.

Water based (pottery) clay works well for helmet sized projects and larger, but requires more maintainence with regards to keeping it moist. If you plan to do a sculpture over several weeks, it is possible to use water based clay, but you will need to take care that it stays covered and moist or it will dry, shrink (as much as 10%), and crack.

Regardless of the material you choose, you need to think out the entire process before you start. Sculpting is the easy part, molding and casting requires a lot more thought and planning with regards to materials and techniques. The decisions you make in the early stages will determine the options available to you later in the process.