MORE wax questions..

I've cast Fuse into a silicone mold, and it worked fine. No experience w/ plaster, unfortunately. I don't think wax shrinks the way porcelain does, so you might have some trouble getting it out of the molds.

Honestly, I'm not sure recasting your parts is going to be worth the trouble... personally I found that finishing wax was a bit of a pain. For me, at least, the advantages of wax were in the early and middle stages, and you look like you're fairly far along. I'd suggest that you do a small sculpt in wax try it out -- even just one part, like a hand or something -- and then decide if it's worth the trouble of casting your pre-existing parts.

 

Thank you for your kind words, Lauren.

I am not familiar with the FUSE or ZEN waxes from Willow Products. Sorry.

These are some threads about carving wax, here at The Joint:

http://www.denofangels.com/joints/showthread.php?3746-Carving-Wax
http://www.denofangels.com/joints/showthread.php?4775-Carving-Wax
http://www.denofangels.com/joints/showthread.php?4840-Wax-question

Edited to Add: Mothi's Just This And That blog has a plethora of useful information
about obtaining, making, and using carving wax as a design material for ball-jointed dolls.

I made and use a batch of carving wax, based on waif's modified recipe of
Martha Armstrong-Hand's carving wax recipe in the book, Learning To Be A Doll Artist.
The above threads go into great detail about all the carving wax recipes.

I use carving wax as in intermediate design material between my original modeling
material (formerly sculpture wax, now Prima Professional Grade Plastilina #2) and
the final doll material (doll composition slip, (or even porcelain, or resin)).
Carving Wax is reusable and I will be able to use it for the rest of my doll making life.

The oil-clay is relatively soft when warm, and is extremely responsive to my touch.
When cool, the oil-clay is much firmer, and can take a certain amount of detailing.
The oil-clay requires an armature, and an armature support, fastened to a modeling stand.
The oil-clay is reusable, and I will be able to use it for the rest of my life as a doll maker.

When I am finished modeling the figure in oil-clay, it will be removed from the armature support
and cut apart in order to make waste molds to cast the carving wax into.

The carving wax can be cast hollow in water-saturated multi-piece plaster molds,
hot-pour moulage molds, or even silicone rubber waste molds, as described in detail
in Tim Bruckner's book, Pop Sculpture. The carving wax is melted, poured
into the mold, and when the walls of the casting are thick enough, the excess molten
carving wax is poured back into the wax pot.

The hollow casting is allowed to cool and harden.

When cool, the carving wax doll part is removed from the mold, trimmed, and work can
proceed to design the joints. Carving wax is tough enough to withstand tensioning, so
it is perfect for test stringing a work-in-progress doll. My Carving Wax Test Doll has been
strung with 3mm round elastic doll cord for months now, and has not suffered any cracking
or other ill effects. She has been taken apart, worked on, and restrung many times.

The carving wax may be drilled, carved, machined, and welded. Welding is generally done
using a wax pen, a jeweler's alcohol lamp and metal wax working tools, or even a
low-wattage soldering iron. Carving wax may be refined to a glass smooth finish.
Various grades of sandpaper are used to smooth carving wax.

So once the carving wax doll parts have been refined, they may be used to make the
final molds for making a porcelain BJD, doll-compo BJD, or even a resin BJD.

Speaking of shrinkage, it is helpful to know how much total shrinkage of all materials will
affect the size of the final doll, especially when working with several materials to make a doll.

For my doll (using MY carving wax recipe):

The oil-clay used for the original sculpt does not shrink. 0% shrinkage.
The carving wax shrinks 2.78%. (The addition of talc in the carving wax recipe helps reduce shrinkage.)
The CS-1000 slip shrinks 6%.
The total shrinkage of all the materials is 8.78%, which I round off to 9%.

So I must make my oil-clay original sculpt 69.25 cm tall to get a finished 63cm doll.

Here's the maths:

1.0-.09 (subtract 9% from One)
.91 (91%)
63/.91 (divide finished doll height by 91%)
69.23076 (this is how tall the original sculpt must be if there is 9% total shrinkage of all materials)

One more example; for a finished 40cm porcelain BJD,
where the total shrinkage is 19% (16% porcelain shrinkage, and 3% carving wax shrinkage)

1.0-.19 (subtract 19% from One)
.81 (81%)
40/.81 (divide finished doll height (40cm) by 81%)
49.38271 (this is how tall the original sculpt must be if there is 19% total shrinkage of all materials)

(^_^)

 

Pottery Plaster should be used for longer term, high quality moulds for repeatedly casting ceramic slip. But Plaster of Paris should be absolutely fine for junk moulds, especially if you are planning on further refining the cast wax pieces anyway and don't plan on casting loads from each mould, as the quality will degrade faster. And it makes for excellent practice before you make your porcelain casting moulds.

When you cast wax into plaster you need to soak the moulds in water so that they repel the wax better, just be careful because when plaster is wet it can be easier to mar the surface. If you soak them in warm/hot water it will aid the pouring viscosity- by preventing the wax cooling down too quickly so that is can spread into the detail better when poured. Take the moulds out of the water, open them up, dab dry the casting surface gently with a soft cloth. Close the mould back up with rubber bands, and pour your molten wax mixture into the still warm, saturated moulds, using a steady and thin stream. Then wait until the walls are thick enough for your purposes and pour out the excess to make the casting hollow. In my experience it doesn't take long before it's time to pour out the excess, and in smaller/thinner parts it might just be easier to cast it solid and then drill out a stringing channel.


As for casting though whole thing; bigger pieces are much easier to cast successfully, so you may as well attempt to cast the torso, especially since you have plaster on hand. Building up shapes in wax is possibly the slowest stage of working in wax. It's not as quick or easy as clay. But once you have your basic shape, the refinement can go very quickly with the right tools. There is a short thread discussing some options for tools and methods here. Personally, even though it can feel slow to build up shapes from scratch I'd usually rather do that than cast parts in wax. For smaller simple pieces especially, the time I would have spent making moulds would have easily been enough time to to just make the part from scratch.


I know it seems obvious but I have to say it: please be safe when working with wax, it can be dangerous! (And if nothing else, it's a pain to clean it off clothes and furniture :p)



Can I ask what made you decide to go from paper clay to wax for your porcelain project?

 

I am not familiar with Fuse or Zen, so nothing to say on that.

The carving wax I use is from a recipe kwmelvin has probably already mentioned.

Making a plaster mold can take some trial and error, especially with where to make the line for a multiple part mold. Plus, carving wax does have a shrinkage of 2.5-3%. So making a plaster mold of your original sculpt (after sealing it properly) then casting wax into a soaked plaster mold will be smaller than the original sculpture. If this is a problem, you may want to start over again from scratch. This can be a good thing too since you will gain experience working with wax and learning techniques.

You can warm the mold a little by soaking in warm water rather than cold. Make sure when you pour hot wax into the mold that it is a single pour or else you will end up with pour lines. You will need to learn your own timing on how many seconds you must wait before pouring out the excess to make your casting hollow. Note, a skinny pour is not a good idea. A pour hold side should be wider than the wall thickness so hot wax can be poured out. You can help cool your hot wax in the plaster mold quicker by putting it in a water bath and letting the water pull the heat out.

You want to make sure when you warm the wax that you are not making it so hot that it starts to burn. It has been a while since I poured wax into a plaster mold, so I don't recall the exact temperature I used.

What tools you use for working carving wax is going to depend on your style. One of my favorite tools is a ceramic seam cutter. I don't know what is is called specifically though. But it has a blade on both sides of the stick and one of the blades is curved. I love the curved side. I also have dental tool, wood carving tools, etc. I also use my wax pen for melding parts together and a cup of wax on a cup warmer while I work. I do have an alcohol lamp, but I honestly don't use it much at all now I use the cup of wax on a cup warmer.

kwmelvin has already mentioned my blog, but the link is below as well.