I am determined to make the concrete Tree Troll almost indistinguishable from real wood. To do that, it is important to understand the complex language of surface texture. The whorls, knots, cracks, and crevices that trees gain as they grow are very characteristic.

Each day I mix up a pint batch of mortar and spend about an hour and practicing, using old weathered driftwood as reference. Pictured here are some samples of the real thing, along with some good tests — and some dreadful ones. Another photo after the jump.


It will take about a month to really get a feel for this. At that point I should be able to teach others a simple set of techniques that get good results.

Contact SilkMermaid.com sculptor Kim Graham at kimsculptor (at) gmail (dot) com

At long last we are removing the rubber molds from the clay. It slips off with astounding ease. This haunting image shows the inside of the face mold. Good, clean, and without flaw.

Two more photos after the jump.

The volunteers did a very good job of making the rubber uniform and very thin. We are only planning to make six castings, so the rubber is a spare 1/8-inch thick! (You may note a lack of tools in these photos. I’m in the process of moving my studio to a new, larger location.)

The necessary job of retrieving the plasticine clay from the sculpture and cleaning it of aluminum foil. This will take an entire day. I will recycle most of the steel armature and scrap the remainder.

About Kim Graham

We have chosen a stretchable silk that can handle all the movement without too much buckling.

We drew the pattern for the dorsal fin with a light pencil and masked the white areas with a liquid resist, then allowed the resist to dry. Next, we stretched the silk on a wooden frame with bulldog clips and rubber bands. After treating the fabric with vinegar, we drew the two silk dyes, intense yellow and magenta, onto the surface. With the vinegar treatment, it is astonishing how much control you can have with the movement of the color; it is very much like watercolor painting.

After the silk dries, Owen will steam it tonight to set the color into the surface.

About Kim Graham

[Left to right: Jasmine Gilbert, Kim Graham, Owen Wolf]

We have begun experiments on the silk for the fins. Owen Wolf, who has been dying fabrics for more than a decade, is working with us find the right look for the Mermaid. My good friend Jasmine Gilbert, a fabulous costumer, is helping with the coloring.

This is the first layer of intense silk dyes. We will set these with steam tonight and then do the second layer tomorrow. It may take many layers, and quite a few attempts, to get the complexity of texture we are looking for. But it is a joy to finally be working with the colors.

About Kim Graham

Three things today: cutting the legs to length, removing the bolts, and opening the shells. We used a contractor’s laser level to sight down the legs, then cut them off with a SawzAll. We then carefully removed the bolts from all the pieces — this took hours!

Near the end of the day, we used a few dozen screwdrivers to remove the first few shells. You can see them after the jump.

As you can see, once a shell is off, it sits correctly on the floor and connects seamlessly with the other shells.

A very rewarding day.

About Kim Graham

Six volunteers today. We finished the mother mold shells and began to put the supporting legs on each piece. We’re doing the legs slightly differently from the hair because the pieces are so large. Instead of using a platform to measure all the supports, we’re just making them really long. We’ll cut them to length later.

Two more photos after the jump.

The strings, secured to the bolts, hold each pair of legs in position until the resin sets and glues their ends to the shells. Afterwards we cut the strings and add additional bracing.

It was a long, exciting, exhausting day.

About Kim Graham

I’ve already illustrated the molding process with the hair (see Moldmaking: the hair one, two, three, four), so I’ll just touch on the high points.

It is very rare today for a sculptor to do monumental work like the Red Silk Mermaid. An artist may sculpt only four or five such pieces in her whole career. The opportunity to make molds at this scale is equally rare, and it offers a terrific learning experience. A team of helpers can accomplish weeks of work in a matter of days. Their assistance is enormously valuable.

To find volunteers, I simply email all my friends in the industry and ask them if they know of anyone who would benefit from this study. In return for the volunteers’ assistance and labor, I introduce them to this work and show how it’s done in a professional studio. True, this is an informal atmosphere and not a standard lecture, but I require the volunteers to get their hands dirty in the process — often for the first time.

Photos of the volunteers in action after the jump.

Day 1 with volunteers: Ten people showed up, a good mix of artists and makers. Everyone was really enthusiastic about the chance to get some hands-on experience. A number of them had seen demonstrations, but only two had actually used these materials. It is my experience that if you give people the opportunity to work on something really grand, they will get it right. And they all did!

They placed the pin and tape walls on everything and finished a first coat of rubber by 4pm, six hours after we started. An astounding amount of work! It was all pretty fun, laid back with great conversations.

Day 2 with volunteers. Ten people showed up again. Some brought some show-and-tell; others brought their friends; still others brought some food. Everyone worked carefully with the materials and did a really good job.

All the rubber is done, including registration.

Day 3 with volunteers: Eight people showed up. Pretty tricky material, but together we worked out a system to keep the hot and quickly curing material moving.

It was a bit fast, but we finished a tremendous amount of work — all the new pin and tape walls and half the mother molds.

About Kim Graham

The small parts — fingers, ears, and fin bases — all get their own molds. We use cheap chopsticks to anchor them to sheets of 3/4-inch plywood.

Specific techniques after the jump.

Drive the chopsticks about an inch into the clay part, then cut the exposed remainder 3″ from the clay.

Drill holes in the plywood with a 13/64″ bit. This is just slightly smaller than the sticks; it makes for a really strong fit. Push the sticks aggressively into the holes. For the heavier parts, use three or more sticks.

Also, instead of using one large ungainly sheet of plywood, use a bunch of smaller ones (16×12″-ish). These are easier to handle in a limited space, and more people can work on individual “sets.”

About Kim Graham

My team and I are preparing the sculpture for molds. We’re taking off the pieces that need to be done separately: the ears, arms, and fingers. We’ve made a mounting bracket of scrap lumber and steel to hold the arms so it will be easy to get around them. We reuse the bracket materials after each job.

Another photo after the jump.

We’ve removed the fingers and added small posts to their bases. These will roughly socket into the holes cut into the hands. When the whole sculpture is assembled later, this post-and-socket arrangement makes these small joints super-strong.

About Kim Graham

Here are some tricks for sculptors frustrated by bilateral symmetry.

First, impress a brightly colored string on the exact centerline of the face, then shine a light exactly on the center string. This makes the differences between sides glaringly apparent and consequently easier to fix.

Second, notice the terminus line — the delineation between light and shadow. You can get this line really sharp by bringing the light close to the sculpture. Concentrate on just sculpting along the terminus line. By moving the light up and down along the centerline, you can capture the volumes more accurately.

Last, take a picture of the piece and put it on your computer screen. Even now, I noticed a bunch of problems just writing this entry! Flipping the image horizontally also makes problems, and therefore solutions, really obvious.

About Kim Graham

To open the mold, remove all the bolts and place screwdrivers in the seams. It is easier if you work three or more sides at once. As one opens up and stops, another will have just enough leverage to move more.

Lots more photos after the jump.

First piece off! Yeah!

Step ahead through a day of intense grinding. I have smoothed and cleaned all the edges. You can see the bolts holding the whole thing together. They are close to the surface and easy to remove.

It is also easy to see the advantage of legs. They elevate the mold to a comfortable level and permit effortless access to the underside bolts.

This little trick will save you hours: brightly colored seams, a different color for each of the edges (in this case, ten). When a mold is disassembled and on the floor, it is impossible to tell what fits together where.

Removing the rubber from the original. Yes, the original clay will be damaged or destroyed in this process.

The mold interior. I have drilled small holes in the registration grooves, one hole every five or six inches.

The rubber snapped into place. Notice how aggressively the rubber is held into the hard outer shell. No slumping or slipping.

The mold exterior showing a hole drilled on the registration line. The drilled holes allow you to see if the rubber is fully connected to all the registration groves. In a mold this complex, it is easy to have areas that don't snap in. Instead, they float. That would mean disastrous distortion in the cast piece. This is how you check to see that it is all correct.

I have encased the T-nut side of all of the bolts first, using a polyurethane resin reinforced with polypropylene fiber. It goes on fast and cures almost instantly.

Again, many more photos after the jump.

All the edges and sides have been done.

Now to make legs that will allow the mold (when I later remove it and turn it over) to stand upright and stable on the floor. I place a large sheet of level wood on the (soon-to-be) underside of the mold.

The mold legs in place

I’ve cut several pieces of wood to length and glued them in place with more polyurethane resin and fiber. There must be three legs per individual bottom mold piece.

With the legs glued in place, I have removed the wood floor.

Here I’ve applied the first, really thin coat of rubber. It flows like honey and gets somewhat messy. This captures all the detail.

I am using Mold Max 30 high-tear-strength silicone rubber from Smooth On Corp. Used with the thickening agent Thi-Vex, this rubber has the most wonderful creamy texture, and it will hold onto a surface upside down.

Many more photos after the jump.

Second coat of rubber, slightly thicker.

Third coat of rubber

For the third coat, I’ve added a small amount of polypropylene fiber to double the strength. You can find this at concrete suppliers; it’s often called “stealth fiber.” I’ve added a bit of color to each batch so I do not lose track of where the last batch was.

Pre-cast registration lines

I press pre-cast registration lines into the last coat. Rubber is pretty floppy and has no structural integrity. These lines prevent the mold rubber from collapsing away from the hard outer shell.

Trimmed edges

I have trimmed the edges nicely to prepare them for the outer shell. Once again, I’m using the steel pin method (used on the armature) to make the hard outer shell pieces. I make several pieces per side to prevent the final casting from locking into the mold.

Mold tape wall with bolts and T-nuts

Another tape wall — but this time with a new addition: T-nuts and 2 1/2 inch bolts to hold the side pieces to one another. It is a very efficient method, so there’s no need for rubber bands, strap clamps, or wing nuts.

Closeup of the T-nut held perpendicular to the surface.

I make sure the T-nuts are perpendicular to the surface. Otherwise the bolts can become crooked and impossible to remove.

(Continued in the next post…)

(As mentioned in “Hair finished – but I need clay,” I decided to mold the mermaid’s hair ahead of the rest of the figure, so I could reclaim the clay for use elsewhere on the sculpture. I describe the entire process of molding the hair using nearly two dozen photos over several posts.)

I start with carefully removing as many of the difficult-to-mold hair pieces as possible — 29 individual bits, plus the main mass! Again, this is shocking; typically there may be two to five additional pieces. I carefully number both each bit and its connection point.

More pictures after the jump.

The main mass with all the extra hair gone.

I divide the hair into two very large mold halves. Here are the initial 1/16-inch steel wire pins placed along the parting line.

Just as before, I use cellophane tape to make a mold wall. It is fast, thin, easy, and cheap. True, it does leave these pinholes everywhere, but this mold is intended for hand layup (finishing), so it doesn’t matter.

I’ve drawn a black line on the mold wall about an inch and a half above the clay. This ensures I coat the rubber to the right thickness in that area.

The cellophane mold wall

More in the next several posts!

I am using “Le Beau Touche” modeling clay from Chavant. This plasticine goes for approximately $4 a lb. It is a mid-level hardness formulated for northern climates. It is just the right density at room temperature, 65 degrees, to be pleasant to work with. In Texas it would melt.

To soften the clay, heat about 2 lbs of it in a microwave for two minutes. Then apply the clay with a spackle knife or trowel. I’m putting on about 1/16-inch and leaving little sparkles of foil showing. This reminds me of the depth of the clay.

I have tipped the mermaid down to get to the top of the hair.

A side shot after the jump.

I never cover the fingers until the shape of the hand is established. The fingers will be the very last thing to do.