Maybe it was a bit too grandiose, but "Myrtle" was made to be a scale model for a much larger turtle intended for the entryway of a casino owned by the turtle clan, a.k.a. the Potawatomi Tribe, in Dowagiac, MI. The plan was that I would reproduce the turtle as shown ten feet tall, and then invite Native American artists from other tribes to use each section of the shell as an individual canvas upon which to depict what it means to that artist to be Native American. This, truly painted turtle, would be located near the entrance for tourists and locals to walk around to view a mosaic of meaningful art. I was never able to find the appropriate person with whom to discuss the concept.

Step 1: Start With a Model

I purchased this turtle figurine from a Goodwill store for 25 cents. It was to become Myrtle, 36 inches long.

As the photo states, "anything can be blown up in proportion." I mentioned on a different Instructable titled, "Rhonda the Rhino," that I would show how I am able to go about determining proportions with confidence.

In an effort to explain proportion, my high school teacher pointed to two objects on the table and said, "It's simple. This is to this as that is to that." You're probably thinking of the same kind of expletive right now that I was thinking at the time. Once I figured out what the heck he was talking about, it has been a critical part of my art for the past forty five years.

The secret is a simple algebraic formula that you keep repeating over and over again until you have derived all the critical dimensions to make a scale model.

I tried a number of search variations on the internet to see if I could find an easy formula to determine proportion so that I could teach others. There was one site where you can plug in the numbers and it will calculate the result for you. Other than that, the other sites were too voluminous and confusing. I just wanted a simple math formula. Anyway, I couldn't find what I was looking for, so, I came up with a simple formula that I think everyone will understand. I'm no mathematician by any means, but it works. Hang in there with me. I know that math isn't everyone's strong suit.

Step 2: Measure, Document, and Then Calculate

Examine the object or drawing you wish to enlarge or reduce in size. Then measure and write down the longest dimension (A or B) of your model. Measure and document the length of the particular part on your model that you wish to scale up or down. You now know two of the four dimensions needed. As long as you know three of the dimensions, you can calculate the fourth. The third dimension needed is simply how large or small do you want your end result to be? The formula can be manipulated to find an unknown whether you are enlarging or reducing.

Using the drawing above as an example, let's say that I know that the small tree is 12 inches tall (A) and that one of the branches (a) that I want to blow up in proportion, is 3-1/2 inches long. I want to make the tree 3 feet tall (so, B=36"). Units have to be the same. In this case, it's inches. I can now calculate the length of (b) so it will be in exact proportion to the model.

Simply replace the letters in the formula with the numbers and cross multiply. Then solve for the unknown. Here's how.

Step 3: Replace Letters With Values

Repeat this calculation until you have all the critical dimensions necessary to start building a sculpture or drawing. The formula works in both 2-D and 3-D, so you can include length and breadth of a sculpture.

It might sound a little complicated at first, but once you do it the first time, the calculation becomes repetitious because you are only changing one number in the equation to find all the widths, thicknesses, lengths, girths, and whatever detail you wish to be exact. I find artistic comfort in knowing that all is.

With that tricky part out of the way, let's look into what it took to make Myrtle the Turtle.

Step 4: Weld Up a Strong and Sturdy Armature.

After I used the small model to derive all the critical dimensions like length, height, and width of each of the parts, it was easy to see a turtle take shape as the wire rod was being formed and assembled. For the most part, I used 1/4" hot rolled steel to create the frame and 1/2" cold rolled steel to connect the appendages.

Once you see that you have the basic shape and proper proportion, you no longer need the model. This is when you start to add your own character. In the case of Myrtle, I didn't want just any kind of turtle, so I made her a mix of painted turtle, box turtle, sea turtle, and tortoise.

When enlarging a sculpture like this where you will be using concrete, if the final dimensions are critical, make allowances for the fact that the mesh layer and concrete layer will add an inch or more to the overall dimension.

Step 5: Stuff the Inside With Pieces of Scrap Foam

Since I didn't have any good photos of the turtle in this foaming step, I borrowed a couple photos from my other instructable in this contest (Rhonda the Rhino) so that you can see the stuff I'm using.

What the foam scraps do is simply take up space so you don't use up so much expandable foam. Notice in the photo that I wrapped the legs of the turtle frame in cheesecloth. I realized later that I did not leave enough space between the gauze wraps to allow for the foam to expand completely. The gauze or cheesecloth should be very loosely wrapped with open spaces between the wraps. The foam needs room to expand, but still be contained to best extent. If the foam can't expand completely, it won't harden. The gauze helps to keep the foam restrained so you don't spill so much on the floor in the process. I even stretch wrap my shoes. It's really sticky, messy stuff to work with as it gets all billowy and pillowy. I highly recommend a full face shield, an apron, and surgical gloves when using moisture cured urethane foam. Cover the floor with sheet plastic. Moisture cured urethane foam sticks to just about everything except HDPE plastic.

Step 6: Carve Away the Foam While Following Contours

With the bulk of the billowy foam carved away, I used a coarse steel rasp to round the contours to match the lay of the steel rod.

Removing the bottom carapace made it a lot easier to work on the legs where they go up into the body recesses. While detached, I foamed the carapace separately while leaving the weld points easy to get to for reattachment later.

BTW. In the background of the photo happens to be another of my sculptures that will most certainly elevate your mood today. It's a rendition of a pregnant crack addict taking a hit off a crack pipe. Here's a brief story of how the piece titled, "Life Sentence," came to be.

A former co-worker's daughter happens to be a gynecologist that adopted a crack baby. I watched the boy grow up from age 5 to age 12. He was most definitely a special needs child. Both of his eyes went off in different directions, so you couldn't tell if he was actually paying attention. Plus, he was like ADD on steroids. I asked my co-worker, "Why does he frown all the time?" She said, "It's because his smile is upside down."

My cousin, who used to work for the juvenile court system in Detroit told me, "I see a lot of pregnant crack addicts come through these doors."

"Life Sentence" is not a piece someone would want in their home. I knew that when I made her. But I also know that the message it sends hit a home run at one of my Marquette Arts and Culture Center group exhibitions.

A little boy, maybe six years of age, while holding his mother's hand as she perused the gallery, looked up at Life Sentence standing on a pedestal in front of him, tugged on his mother's hand, pointed to the statue and said, "Look mommy, that lady is smoking a cigarette, and she's going to have a baby." The mother looked at the sculpture like she just ate a lemon, shrugged her head in disgust, and moved on to the next piece like she was angry.

Sorry for the diversion! Back to Myrtle!

Step 7: Tricks With Green Concrete

A layer of steel mesh had to be applied to the legs first before the concrete was applied, but I decided to show the mesh process later so that I can present it in more detail along with the concrete process. You can see now why I elected to remove the carapace to be able to get to all of the legs.

Notice that Myrtle has a defiant stance and a slight smile. She's confident and friendly.

To make the scales on the legs, I thinned out some mortar to about the consistency of toothpaste and put some in a Ziploc bag. Then I squeezed all the concrete to one corner of the bag, snipped about 1/4" off the end, and used it like a cake decorator. Starting at the bottom, I squeezed an amount of mortar onto a fresh green base and worked the scales upward like putting shingles on a roof. It's best to work on only one appendage at a time and mix up only an amount you need to accomplish that part. The mortar will lose its plasticity if it sits too long.

Working green into green means that you apply a thin base layer of fresh concrete onto the foundation layer so the next layer will stick to it easily. It also ensures good contact. If the base layer dries out at all, it's difficult to get the new layer to stick. Work within an area that can be accomplished before the base layer starts to dry out. Misting lightly helps extend the working time.

The video demonstrates a couple other effects you can create by working green into green. It's part of a twelve foot tall installation piece for the Erickson Center for the Arts in Curtis, Michigan, a recent contract I had to get out in record time. Sorry, I just woke up after spending the night in my studio.

You can see lots of examples of what I call Living Tree Art on my website. I also teach how to make trees.

Step 8: Connect the Carapace to the Shell

After wet curing and letting the concrete harden overnight, I re-welded the carapace back to the shell and then foam-filled the inside cavity. The photo above shows you how to protect the concrete on the legs when the foam is applied. The foam won't stick to HDPE plastic. It's the most common kind of sheet plastic available. With the excess foam removed, I was able to carve out the shape of the fleshy part of Myrtle's body where her head retracts.

The next step is scary stuff.

Step 9: Blood Lath!

I hate this stuff, but I've made a lot of cool sculptures using it.

Attach the lath securely by sewing it on with a needle and thread. Except in this case, the needle is an 1/8" copper coated welding filler rod about 30 inches long, smashed on one end with a hole drilled in the center of the flat spot. The thread is rebar tie wire.

Repeatedly pierce the piece through and through tugging it tightly after each pass so as to draw the mesh in snugly to the body of the form by pulling from the opposite side. The close ups show details on the rear, side, and front.

Finally! Apply the concrete.

Step 10: Apply the Concrete to the Shell and Carapace

I applied the mortar to the underside first by deeply and completely filling in all of the voids of the mesh, then flipped her over and did the same to the sides and shell working my way upwards.

Uniformly bulking up the concrete is my insurance against cracking due to errant impact later. There is a point in time as the concrete sets up to be a little like plastic where you can tap on the sculpture and move the cement around without causing cracks in the concrete. The outlines of the shell sections were not excised, but indented.

Before the concrete sets up completely, I burnished the surface of the shell and carapace with the back of a spoon. Burnishing closes the pores of the concrete to give it a smooth feel to the touch and a slight glisten.

I formed the skin over-flap part where a turtle's neck retracts into the shell using plastic wood filler. Once hardened, Myrtle was ready for painting.

Step 11: Base Coat of Primer Paint

Myrtle got two coats of Zinsser 1-2-3 indoor/outdoor primer.

Step 12: Finish Paint

Two coats of a good quality black acrylic paint provided great contrast for the finish details that were not exactly intended.

I thought that keeping the lines not too different from those of a painted turtle would offer a basis for universal recognition. After that, the rest was ad libbed. At the time I made Myrtle, I had just learned about Oaxacan Art which are wildly colored caricatures of animals. It's actually quite refreshing to just go nuts with color and paint.

At first, I was a bit concerned that children might be afraid of Myrtle because of the way I painted her, but that was definitely not the case. Children were drawn to her like a kid magnet. For two years, I had Myrtle just inside the lobby door at the Marquette Tourist Welcome Center in Marquette, MI where I still work part time. I thought that I would have to repaint the head before the first summer was over from all the petting.

Many times I saw a mother with a kid or two in hand, walking fast on her way to the bathroom only to get jackknifed at the door when the kids all of a sudden dash into the lobby to get a closer view of Myrtle. The reaction to Myrtle still amazes me.

Step 13: Myrtle Finished

Mission Accomplished!

Step 14: Security for Myrtle

I ended up selling Myrtle to a lady friend named Peggy who wanted to put Myrtle in her front yard against my concerns over theft. Marquette, MI is a college town and unfortunately, you have to worry about such things. You don't just put a $2400 sculpture in your front yard for anyone to do a grab-and-go. I had to take extraordinary measures to make sure Peggy's Myrtle wouldn't be stolen. The video mentions two of the three elements of protection. There have been attempts to steal Myrtle, but I'm happy to say she's still on display in front of Peggy's yard.