New Mexican Sculptor

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New Mexico, United States
I'm living in New Mexico where I sculpt and paint. After a long absence from art, I am now creating smaller bronze figures. This blog is mainly devoted to that work.

Monday, November 22, 2010

Moldmaking 101

By C. R. Larkin

Most small sculptures like this are done in a series, that means that copies need to be made. To get a good copy, you need a good mold. Many people do molds that degrade over a long period of time, or which they can get only one or two copies. I would like to make at least 15 in this series, perhaps 20, so I need a mold that I won't have any trouble with-- and that means spending the money now for better materials.

I have chosen to use a good RTV Silicon Rubber mold so that the “library life” is fairly long. I also need to choose my molding rubber on the basis of things like toxic fumes as I am working in a house, and also how pliable the rubber is. I will make a brush-on mold with an auth body putty (Bondo) mother mold. The alternative-- making a solid “block” would cost too much. As it is, I bought a gallon of the molding rubber, a regular tine based catalyst, and a thixotropic catalyst.

I begin this mold by taking the sculpture off its base, and lay on its side on a large base-board. I intentionally made the armature extremely rigid and tough, (remember the auto body putty in part 1?) and also used very hard plastaline. In the photo, you can see many of the things I will need for mold making, the most important of such is a decent gram scale. I got a small but accurate scale for about fifteen dollars.

My first step may surprise some people: I coat both sides with one layer of silicon rubber mold material, waiting first for one side to set, and then the other. This primary skin will pick up all surface details. I did this first because I did not want to risk any marks during the molding process. I must say that it is impossible not to have any mars at all. At certain points in the process, I will be able to buff out any imperfections. Here, you can see, one side is covered and I begin to create the foundation of the clay wall I will be using as a parting line.



Next: I continue to build the clay wall foundation and start inserting clay in the narrow cracks between the foundation and the body of the horse. I want as few things to actually touch the body of the horse as possible, so there is a lot of “floating” material.



Close up of how parting line will divide the body of the horse in front. I have decided to use a “Z” shape to catch all the legs so I won’t need to make more than a 2 part mold.



Continuing clay wall:



“Z” line crosses the belly. Front right, front left, cross belly, then hind right, hind left.



Over several days the mold is built up, including the parting line. When the rubber is 1/4th inch I further build up and stabilize with a cheese cloth layer.



Once I have enough mold rubber on the mold, I pour the mother mold, using another wall made of cardboard to keep the Bondo from sliding off. This takes an entire gallon can of Bondo.



When the Bondo has set, I then flip the mold to start on the other side. Here is the next side of the horse:



I carefully remove all the clay and pink insulation foam. And clean up things like “drips” which you can see now point upwards.



As you can see, the mold is no longer on the board, which lightens it a bit. It is parked in its mother mold now. I want to make sure the two halves of the parting line will not stick to each other, so I put a release layer ONLY on the parting line where the clay wall once was. When I add more rubber now, the rubber will stick to the horse, but not to the parting line. This is the final preparation step before starting the next side of the mold.



I must wait over night for it to cure to make absolutely certain that the 2 sides do not stick together. Since it is winter here, silicon is notoriously slow to set, and molding times are longer.

I’ll post a few more pictures, but basically the same procedures will be followed on the second side. First the mold is built up, then a cheese cloth layer. I will build another paper wall and pour my Bondo mother mold and when that is set, I will crack the mold. I’ll probably need to do a little cosmetic work, but that’s about it.

The next post will show resin casting. I want to pull a resin just to have a few to show off.

See ya,
C. R. Larkin

Sunday, November 21, 2010

Down From The Clouds Pt. 3

By C. R. Larkin

I took time off from work just to finish the sculpture. The mold will be started in a few days. I ordered the supplies and they should be coming in by Friday. I will have a few thoughts on the whole process to finish up. In the meantime, I will work Thursday, Friday and most of Saturday exclusively on finish work. I feel it will be enough time.

Anyway, here I place the last leg of the "creation" (except the tail):

As you can see I also have the last foot on. I am skinning the hoof armatures so they are thicker and have all the hoof parts (coronary band and etc.) I have also moved the leg down as suggested.

A few things need to be done again-- the mane, for example.

I work on the surface muscles. I think I have the region between the end of the ribs and the hips (waist?) worked out on this side. The horse now has 2 hind legs.

After a couple more days: Done--

It took about 45 days to sculpt on a random schedule. My sister died (one year older than me) and I did not feel like working for a while. If I had worked 8 hours a day, It would have taken about a month. This is in plasticine. I have the mold making materials and will make a mold shortly for both sculptures. Now, a few instructions: I am a New Mexican artist who has been influenced a bit by the Prairie School. (I actually studied under a famous southwestern artist who has a "School of" attached to his name.) I like a lot of angles and tool marks, but I like smoothness too. (conflicted). I seek a mild stylized effect not hair-by-hair realism. I find this in most of my work. It borders on realism, but in a way is still stylized. I really think I am finding my "stride" to use a horse metaphor.

Please do not dwell on the fact that I have a terrible camera. Sometimes I get criticisms of my camera equipment more than the piece of art.






Next post: Making the mold