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Wax Flesh and Steel Bones

Tools of the Trade

Getting Ready to Work

Select a block of wood large enough at the base and heavy enough to support your planned sculpture.  Drill a hole in the block of wood a little larger than your aluminum wire and set a piece about 8” in length into the hole, securing it with melted wax.  If you plan to use a turntable, secure the block of wood to the turntable with wax. 

 You may want to wrap the handle of your dental tools with string or leather, as they tend to heat up in use.  If you wrap it in string, you can rub melted wax onto it and it will stay put. 

Using the aluminum wire, create a basic skeleton for your work.  You are going to want to “impale” your piece on the rod attached to the wooden block.  You can plan to simply stick it on, or you can attach the bottom part of your skeleton to it.  You don’t want the base to go too deep into your sculpture, so fold down the rod to a manageable size.  Multiple pieces can be held together with masking tape.  Don’t get carried away with detail.  Overlay the skeleton with tin foil to create the basic shape of your sculpture.  Keep the foil loose.  You need to be able to compress or shift the understructure as you go.  If you use masking tape to attach any foil, make sure that it ends up under foil, as the wax will not adhere to tape. Again, don’t waste time and effort on details.  

Add denatured alcohol to your torch to the fill line.  Allow the wick to absorb some fuel, and then light it.  If it refuses to stay lit, discard the original wick and make a substitute wick by splitting threads from a rope mop.  This is a common problem with these torches.  Handle the torch with care.  The flame is almost colorless and burns extremely hot.  Gently squeeze the torch to produce a “finger” of flame that you can use to melt and soften wax.  

The wax is sticky; it’s best to keep it wrapped in foil.  You will soon find it all over your work area.  It doesn’t come out of clothing.  Within reason, the alcohol will dissolve it.  It can be removed from your work surface with a razor blade.  There are two basic approaches to applying the wax.  The first method is to shave off “leaves” of wax, soften them in your hands and press them onto your foundation.  Using your fingers and the alcohol torch, blend each piece as you add it.  Alternatively, hack off a chunk of wax and melt it in a small potpourri crock-pot.  Using the dental tools and Popsicle sticks, apply wax to cover your base shape. 

From there on you are sculpting.  Here are no wrong paths or wrong tools.  You can use various materials to add texture, such as pressing burlap into softened wax.  To create a smooth finish, puff the torch repeatedly against the area you want to smooth.  Annoying air bubbles will surface and pock mark your surface, but they will soften away with patience.  The texture of your final surface will be duplicated in later castings.  If you want a dull surface, use fingers to create a smooth but dull surface.  If you want a glossy surface, use the torch.  If you want a textured surface, then use tools to create it. 

When you are completely finished, it is advisable to take photos before proceeding, especially of complex sculptures that will have to be cut into pieces for casting.  This is a distressing experience, and you probably want to create a simple piece for your first effort to avoid this. 

Making Your Mold

If you are planning to cast in bronze, the foundry will create the mold of your original for a fee.  There are three advantages to making your own mold: It’s cheaper.  You can use it for other casting mediums.  And you have a hand in the creation of your work for a greater number of steps.  If you choose to make your own mold, to begin with you will make a rubber mold.  You’ll need several tubes of silicone caulk for a medium sized piece.  Make sure that you have 100% silicone caulk, not silicone 2.  White caulk is best; the clear is brittle and tears. 

 Step 1:  Examine your piece and decide whether it will have to be cut into more than one piece for casting.  If it has complex angles and shapes that can’t be removed from the mold, then you will have to cut the sculpture into pieces that can.  If you do need to cut it up, use a thread or wire to cut through to the aluminum skeleton, and a saw or wire cutters to clip through the “bones”.

Step 2:  Create a pouring spout.  This can be of wax, foil, metal, glass, plastic; anything the rubber won’t stick to.  The pouring spout needs to be positioned where all points of the mold are downhill from it.  If this isn’t possible, you may need a second pouring spout or to reconsider whether you need to cut up the original.  If you have an area where a bubble is likely to be trapped by the pouring wax, you should also attach a slim line such as a straw or coil of wax, which will trap the air and allow the actual image to fill with wax.  The pouring spout should be attached to a rough area of the original, because the attached spout will have to be snapped off and the area repaired.

Step 3:  If you have sensitive skin, use surgical gloves when handling caulk.  Handle the caulk in a well-ventilated area, preferably outdoors.   If you have asthma, be prepared for breathing problems.  Lay out plastic on your work surface.  When you cut the tip off the caulk, save it to use in reverse as a cap.  On one corner, squirt a pile of caulk.  Using your fingertip, smear a very thin layer of caulk over your whole sculpture.  It should be so thin you can see the color of the wax through it.  Work fast, the caulk begins to set up fairly quickly and it will make lines where fresh caulk is laid against set caulk.  Once this thin layer of caulk is laid on, set the piece on the plastic to cure for at least 24 hours. 

Step 3: Determine the line that you will cut along to remove the sculpture from the mold.  Mark this line with a series of straight pins pushed through the 1^st layer of rubber and barely set into the wax.

Step 4: Half fill a 1-gallon tub with cool water and squeeze about half a tube of caulk into the middle of it.  Stir it for few seconds, till the silicone becomes rubbery and clumps on your stick.  Spread gobs of rubber about ¼ “ thick evenly over your entire sculpture.  Work fast; it sets up in only a few minutes.  Don’t worry about protrusions; they will only help the next coat adhere.  Once it stops being willing to stick it is useless.  Wait at least a few hours and preferably overnight before repeating.

Step 5: Repeat Step 4 until the rubber is as thick as the straight pins are tall evenly over the entire sculpture.  Pay special attention to protruding features, as people tend to let the mold be too thin over these areas.  Don’t cover the straight pins.  After you apply the last coat, while the rubber s still malleable, squirt some dish soap onto the surface and the rubber immediately is inclined to become smooth.  Use this to smooth out the surface of the finished mold.

Step 6:  If your piece is very small, fist sized or less, you will not need a “mother mold”.  At this point you will use a razor to cut clean and straight through the rubber to the wax below, following the line of the straight pins. Cut straight through all the way down the wax in a clean line. Don’t worry about hurting your wax original; you have a mold now!  Carefully remove the straight pins.  The liquid inside the mold is nasty and likely to trigger asthma.  DO NOT open the rubber mold yet if you plan to make a mother mold!

 Making your Mother Mold

If your piece is of any size, you will need a mother mold to support the walls of the rubber mold when casting a piece. 

Step 1:  Get a box at least as large and half as deep as your rubber mold.  Set your mold into the box and pile sand or dirt up to half the depth of the mold.  If you have any protruding shapes, you need to lay the mold down so that the half point for the dirt is halfway up the side of the protrusion, in order to allow you to remove the mold from the mother mold and put it back.  Remember that your pouring spout has to stick out of the mold, so you may need to use a plastic cup or funnel to shape the plaster in a way that will allow you to pour into the mold.

Step 2: Once you have piled and packed dirt around the rubber mold, you need to soap up your mold.  You can spread the dish soap directly on with your fingers, but it is hard not to get dirt mixed in.  Or you can mix dish soap with water in a plant sprayer and spray it on liberally. 

Step 3: Now mix your plaster.  Follow the directions on the bag.  Handle the dry plaster with caution; it is dangerous to breathe.  You may want to wear rubber gloves in handling the plaster.  Mix enough plaster to cover the exposed part of the rubber mold 4” or more in thickness.  For large molds, you can get a mixer attachment for your household drill to stir it evenly. 

Step 4: You only have a working period of perhaps five minutes.  Pile the plaster on all over the exposed rubber mold; it will start to heat up as its chemical reaction begins.  It’s a good idea to give this side of the mold a flat surface on which it will rest.  When you feel it starting to get warm and stiff, then you are almost out of time, hurry and use the last of the plaster.

Step 5:  As you are finishing, use your hand to smooth the exterior of the mold to make it easier to handle. 

Step 6:  Once the plaster has set up and is cool, turn the mold out of the box.  Avoid letting the rubber mold slip loose of the plaster.  Brush away all the dirt and set the mold plaster side down on a garbage bag or some other protective surface.  Soap this side of the mold.  If you wish, you can also lay plastic wrap over the edge of the plaster, but the soap will generally provide a good seam for the mold. 

Step 7:  Mix more plaster and complete the other side of the mold. Remember to leave your pouring spout intact.   Allow the mold to cool and completely set up.

Step 8: Gently pull apart the two halves of the plaster mother mold and remove the rubber mold.  Use a razor to cut clean and straight through the rubber to the wax below, following the line of the straight pins. Cut straight through all the way down the wax in a clean line. Don’t worry about hurting your wax original; you have a mold now!  Carefully remove the straight pins.  The liquid inside the mold is nasty and likely to trigger asthma.  I use gloves for this step, as the liquid really irritates my skin.  Remove your original.  You don’t need to be careful with the original, since you can now duplicate it.  But if you have major problems removing it, you may need to cut the mold further.  You want to minimize the opening in the mold, as the seams are prone to leak.  But you have to be able to remove your copies without destroying them.  Allow the rubber mold to dry completely before using it. 

Casting in Plaster 

Advantages:

 Disadvantages

 I have to confess that I haven’t had a lot of luck with plaster.  I can’t quite seem to get the recipe right.  However, with a little practice I am sure we can all take advantage of this inexpensive medium. 

 Step 1: Since plaster is pretty thick, if you plan to do plaster casting you should include a pouring spout that will accommodate it when you create your original.

Step 2:  Make sure the mold is dry and clean of debris from previous uses.  Using straight pins stuck lightly into the mold as top and bottom anchors, wind the mold tightly shut with thread or fine string.  If you don’t have a mother mold, brush the entire seam with melted wax to create a watertight seal.  As plaster is rather thick, you may find that you don’t have to do this, but it doesn’t hurt.  If you are using a mother mold, settle the mold into it, making sure the seam is evenly and well closed.  Close the mother mold and fasten it shut with duct tape, a bungee cord, or whatever. 

Step 3: If your mold will not stand with the pouring spout up, brace it so that it will.  For smaller molds, you can use your rubber-mixing bucket filled with sand or cat gravel to hold the mold at whatever angle you please.

Step 4: Mix plaster according to directions.  Pour into mold, allowing it to slide in along the edge of the pour spout with a gap to allow air to rise back up out of the mold. For very large pieces, you may want to stick some filler like fabric into the center of the mold to strengthen the piece.  If you do this, pour in part of the plaster, quickly insert your filler, then continue pouring plaster. If it slops over the edges of the mold, use your finger to cut off the wet plaster so you don’t have a solid piece stuck to your spout.  Allow to set up fully.

Step 5: Remove the rubber mold from the mother mold, and the piece from the rubber mold.  If it breaks, you can probably glue it.  If not, or if the copy is imperfect, toss it and try again.  Remember, plaster is very cheap.

Step 6:  From here you are on your own.  Clean off flashing and brickle with a knife or dremmel tool.  Paint, decorate, and mount your piece to your heart’s content.  Almost any kind of paint and many kinds of glue work on plaster, so go wild. 

Casting in Resin

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 Disadvantages

 Casting in clear polyester resin is rewarding but can also be very frustrating.  It is not a forgiving medium. Although it’s strong, it is also brittle and must be handled as if it were the glass it resembles.  I understand that opaque resins are more resilient, but I haven’t found a source to purchase them locally. 

 Step 1:  Make sure the mold is dry and clean of debris from previous uses.  Using straight pins stuck lightly into the mold as top and bottom anchors, wind the mold tightly shut with thread or fine string.  Brush the entire seam with melted wax to create a watertight seal.  This is an important step; the resin is thin, maybe thinner than water, and will leak out of your mold given the slightest opportunity.  Since the resin has little mass, you probably won’t need a mother mold, but if you are using a mother mold, settle the mold into it, making sure the seam is evenly and well closed.  Don’t allow your wax to crack off!  Close the mother mold and fasten it shut with duct tape, a bungee cord, or whatever. 

Step 2: If your mold will not stand with the pouring spout up, brace it so that it will.  For smaller molds, you can use your rubber-mixing bucket filled with sand or cat gravel to hold the mold at whatever angle you please.  Don’t use any materials you can’t afford to lose, if the mold leaks, it will ruin your container.

Step 3: Wear gloves.  The resin is sticky and gets everywhere.  Work out of doors if possible, the fumes will knock you down.  Mix resin according to directions in a glass mixing bowl.  You only want to pour to a depth of 3-4” at a time, and then allow it to set up and add another layer to large pieces.  The chemical reaction produces a lot of heat and if you pour too thick the piece will crack.    Pour into mold, allowing it to slide in along the edge of the pour spout with a gap to allow air to rise back up out of the mold. For larger pieces, you may want to stick some filler like glass marbles into the center of the mold to strengthen the piece and extend the resin.  One of the best things about resin is the ability to insert objects into it, which can be seen through the transparent medium.  If you do this, insert your filler after the first layer of resin is poured, setting it at the desired placement, then continue pouring resin by layers. Don’t let it slop over the edges of the mold.  Allow to set up fully.

Step 4: Remove the piece from the rubber mold.  While the mold doesn’t really stick to the resin, it does cling to it, so you have to peel it away carefully.  The resin is abrasive and tends to tear up your mold, you are likely to want to pour a wax copy and make a fresh mold after several uses, or perhaps before you even use the mold the first time.  If the piece breaks while you are removing it, you can probably glue it with epoxy.  If not, or if the copy is imperfect, toss it and try again.  There is a certain amount of loss, as there is a race between when the resin heats up enough to melt your wax seal and when it becomes thick enough not to slip out of the mold.

Step 5:  From here you are on your own.  Clean off flashing and brickle with a needlepoint pliers or dremmel tool.  Be very careful, you can easily break it where you don’t want to.  Don’t be deceived by its strength into forgetting its brittleness.  Decorate, and mount your piece to your heart’s content.  Almost any kind of paint works on resin, so go wild.

Casting in Paper

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 Disadvantages

 Casting in paper pulp is fun and a great project to do with kids.  It’s a forgiving medium and the paper itself is free and almost infinitely recyclable. It’s sturdy, with a strength and weight similar to that of paper egg cartons. 

 Use the article on papermaking to create your paper.  You should make about twice as many sheets as you think it will take to cover your mold, as you have a lot of waste.  This process works best with bas relief (flat, open topped) molds. 

 Step 1:  Take the sheets of wet, newborn paper and lay them into the mold one deep.  With a sponge, press each sheet into the details of the mold carefully.  If the paper tears, pull off a piece from an extra sheet and patch it, pressing along all seams to try to integrate the separate pieces.  Once you are done, throw any spare scraps of paper back in your water and recycle them. 

Step 2: Allow the paper to fully dry, and then gently pop it out of the mold.  If it doesn’t work out, toss it back into your pulp bag and try again.

Step 3:  Clip off any flashing or unwanted material with scissors or a serrated knife.  Paint, decorate and mount as desired.  Almost any paint or glue will work on paper. 

Casting in Bronze 

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 Disadvantages

 Step 1: Research and price foundries, select and make pre-arrangements for casting. 

Step 2: Seal the rubber mold with thread, but no wax.  Insert it into the mother mold.

Step 3:  Melt wax until the surface is glossy but doesn’t smoke or smell bad.  Pour into the mold along the edge of the spout, evenly to prevent “tide lines” from forming on the walls of the mold.  Fill the mold with hot wax in this wax, and then pour it back out.  Be very careful, the wax will burn you badly.  This has set the exterior of the piece, now you need to thicken the walls of the copy.

Step 4:  For bronze casting you want to create a hollow mold.  So you will only pour about 1/3 of the mold, then rock the mold around to evenly distribute the wax to a thickness of perhaps ½”.  Check with the foundry about the desired thickness.

Step 5:  Remove the copy from the mold.  Using your original sculpture techniques, clean up the copy and make it exactly the way you want the finished product to look.  

Step 6: Photograph the finished piece; pack the copy in bubble wrap and popcorn and ship to the foundry.  Include the photos so they can reassemble it or repair shipping damage.  If you are hand carrying the piece to the foundry and you are concerned about heat, carry is in an ice chest with cold water.

Step 7:  The foundry will have you select a base and decide what sort of patina you want.  There are a lot of choices; you may want to look at some finished works to get an idea what you want.  Bring a photo of the base and patina you like to the foundry if you are uncertain of terminology.

 In Summary: