Dividing Wall

[Predasaurus]

Hey guys,

I am about to do a mold out of ultracal, and I am thinking, do I need to do have a clay wall, or can it be out of another material? Or instead of a dividing wall, can I just do one half at a time?

Thanks,
Eli

 

[Untamed]

Well I'm sure you could use a different material. I guess it depends on what material you use. The cleaner your edges are on the halves of your mold are the easier it will be to demold. plus if you have a clean seam line where your 2 mold halves meet up it will give you a much cleaner seam line on your finished product. I would definitely recommend using some cheap clay for your dividing wall. it also depends on what you are molding too. I have watched one of Stan Winston school of character arts videos and they have a whole video on molding with ultra cal. what they did was use drywall and wood to build up a base around their bust sculpture. Then they added a thin layer of cheap water based clay on top of the drywall sheets to make the actual division part of their mold. My experience is that the more work and time you pretty up that dividing wall the easier time you're gonna have with the demolding process. hope this helped
 

Trevor

 

[Predasaurus]

Thanks Trevor, that was helpful. But how about just doing one half at a time?

 

[ptgreek]

you need a wall to actually form that single half. otherwise where would your splash coat go? you remove the wall after your first half is done ..vasaline that half ..then mold up the other side ..so yes ..you need a wall. I dont know what you are molding, but if you plan on using ultracal, then yes use clay ..white clay is cheap

 

[Predasaurus]

K. Thanks for the info.

Eli

 

[Skrull]

you need a wall to actually form that single half. otherwise where would your splash coat go? you remove the wall after your first half is done ..vasaline that half ..then mold up the other side ..so yes ..you need a wall. I dont know what you are molding, but if you plan on using ultracal, then yes use clay ..white clay is cheap

Take ptgreek's advice! The guy is a master!

 

[wonko]

Yeah, George will never steer you wrong.  Not sure exactly what you're molding, but I remembered a video posted here a while back by one of our members.  It shows how he molded his head sculpt  http://www.youtube.com/watch?v=d8hYA0zV4qI that might be helpful.

Brian 

 

[Giles]

I've watched that video about 10 times over the last 3 years, it is pretty good.  From personal experience on my own plaster mould, although it was only a chestburster (so quite small) I didn't make the edges wide or thick enough so I had a very brittle mould edge as I tried to use as little clay for my wall as possible.  Big mistake as I couldn't get the right leverage, the mould was too thin on the edge and I nearly lost the mould and the sculpt!

Take your time and devour every source you can! 

 

[Predasaurus]

K, I'll use it. And by the way, I am molding a predator head sculpt for a latex mask.mold will be out of ultracal. I think it might be a little difficult for my mold because there's a lot of areas which weave into the mouth. Not sure if you get what I mean, but I'm worried that when I mold it the sculpture will get ruined.

Eli

 

[ptgreek]

do not expect the sculpture to survive the molding process at all. ..but thats why you are making a mold in the first place ..to make duplicates. The areas you are referring to are known as "undercuts"

 

[Giles]

Sorry Predasarus, I probably didn't explain myself properly.  Because I tried to make my mould as cheaply as possible, I nearly ruined the plaster mould, which would have meant breaking the mould apart which would have damaged the sculpt completely. That is what I meant by taking your time and not trying to cut corners and/or cost!

 

[Predasaurus]

Thanks guys. So to sum it up, do about 1-2 inches of ultracal reinforced with burlap, and whatever way I mold the sculpt will be ruined. I was also wondering which way is the best to make the wall? Meaning horizontal or vertical. I'm thinking vertical, thogh

Eli

 

[Predasaurus]

Another question, my front half of my mold is Not cooperating , and I was wondering what is the best way to demold?