Process of creation of a bronze sculpture daydream

Grigory Gurevich, "DAYDREAMER", bronze. SOLD.

Description of a process of preparation for a bronze casting.

One year college course.

I sculpted this piece from a water-based earth clay while teaching my students process of preparation a sculpture for casting bronze. When I finished my clay image, next first step is to make a plaster negative from plaster. Plaster and clay do not bind together. There is no fear of connecting those two materials to each other. When plaster hardens, clay must be scooped away from it. Because of it, as well as a preparation for the next step, plaster must be done in several sections. In order to achieve it, shims (small rectangular or square plates from aluminum or plastic) must be inserted in clay sculpture as a wall, which divides one section from another. When shims are on plaice, plaster is splashed all over Kalyn almost to a surface of shims. When plaster hardens, it waged with a chisel and a hammer away from lay original and washed with water well. Inner surface of a negative must be treated with thin layer of clay not to permit binding with another layer of plaster which will act as a positive (it will look exactly like a original clay sculpture, but now from plaster).
All sections of the negative now have to be tightened together. For Bette matching seems, on the thickness of each plaster sections with a half circular Chinese looking carved indents in respond to opposite sphere, so pieces will stabilize and will not move away from each other. Than house rope or robber is used to the sections together. Now negative is turned up side down, so liquid plaster will enter sculpture from open space on the button of negative and freshly mixed plaster is poured with Serbian interval inside the negative and negative must be turned around and sideways for plaster being evenly distributed inside of a negative to achieve thickness of about one and a half inch. After inner layer of plaster (now positive) is hard, negative sections can be taken away. With the slight pressure they are coming out with no difficulty. If negative is in good shape, sculptor has a chance to cast another plaster positive. If that is a goal, negative has to be not less than 3" thick and high quality.
Now we have our plaster positive. It has many imperfections: bubbles, dents, marks of divisions from sections connecting. After plaster is completely dry, chiesels of different shapes , patching tools with fresh plaster are used and at the end sandpaper of greeds from 100 to 300 is used to smooth and perfect a surface of our positive. In older times shellack was used to cover pores of plaster, but now any lacquer or enamel, or acrylic can me used to do that.
Before the next step, which is making robber negative, surface of our treated with lacquer original is sprayed or brushed with a special solution, invented about 40 years ago-"separol". It served a purpose of easy separation of a robber negative from treated plaster original.
Now we need to make two negatives: one will be flexible from a robber and another one from plaster to support robber.
Today there are about 50 different kind of robber materials are invented to create a negative. Some even do not need a second supporting plaster negative. It all depends on size, purpose edition and cost. Robber for casting can be very costly, so plaster reduces expense, but inkrieces human labor.
 Generally there are two ways of making robber negative: one is brush on, and the other one is pour in. Brush on is a ride ours and long process, relating to pour in. This one is done quickly, only you have to wait until robber will harden. In first case plaster supporting negative is done after robber is set, but in a second case, plaster negative is done before robber is poured in.
Here is a quick description of brunch on process: separol is sprain on the positive and many layers of robber are applyed over until thickness will be about not less than 1/4. Than again, robber is sprayed with separol and minimum one plaster section at the time is created with the indents to respond to a next section until all sculpture will be covered with sections. For my "DAYDREAMER"I need only two sections, no matter if I choose brash on, or pour in method. Actually I used second one.
Pour in is more complex: I have to prepare slobs of clay (slob is very identical to preparation of a flour when you make pancakes. It is a flat clay made on a burlap. Or you can roll it over, or you can cut it with the string between two sticks of wood). Apply slabs evenly over your positive.
Now we have to do again plaster negative, like we already did once at the beginning. I will not describe it, but the important detail, we have to carve the opening in our plaster on the top, through which we will pour robber. It will support robber.
Here is an interesting trick: when plaster hardens, we need to mark with any clear marker position of our plaster negative before separating it. It is also extremely important not to move our original. ONLY AFTER YOU MARK POSITION OF A NEGATIVE, take sections away from each other. NOW OUR CLAY  WHICH COVERS ORIGINAL IS EXPOSED. Carefully remove clay from our positive, not moving it. Sections again, must be treated with any sealer and sprayed with the separol. Now place sections of plaster and thigh them together with the ropes. We need to use cay to close any halls we can see in seems of plaster .in other way, if we pour robber it will leak through any tiny halls or cracks and it will very costly result, not even talking about huge mess. Now we can pour robber in space between original and plaster negative. If robber doesn't leak-we have success. Perhaps next day it hardens and we can remove plaster sections. Now , very carefully, we need to cut robber, trying not to make scratches on plaster original, if we want to have it in good shape. But, it all depends on our goal. We won't be using it in the future. The purpose of this original is only to make a molds for a bronze casting.
Time to melt our wax and to pour it gradually inside of our robber mold. Thickeners of it determines how thick will be our bronze piece. It means how heavy it will be and how much bronze will be used and it means how expensive will be our piece. When wax hardens, we free it by separating sections of plaster and robber. Again, wax cast has many imperfections and with the lower temperature melting wax we fixed all imperfections with the hot special tools and bringing wax to a best shape possible. But it is not everything: now we have to glue sprooses. Sprooses are channels in which melted bronze will run through inside of another, now ceramics negative. My piece had about 12 sprooses from the top to the bottom. Sprooses are about 2" in diameter. The goal is to spread sprooses throughout the body of a peace tat way, that melted bronze will be joined before cooling. Sculpture now looks like it has12 wax branches and on the top of connected together branches is a wax cylinder.
One more step before pouring the melted bronze: this part I was not being able to do. Foundry ( it is a special atelier where professional casters and chasers melt and pour bronze) makes ceramic negative around the wax and also they make a filler around inner part of our wax. When it is ready, finally melted red, hot bronze is poured through a wax cup on the top, burning wax and filling ceramic negative until it flashes over. Now bronze is cooling down depending on how big is our piece.
And this is not the end. Al sprooses now must be cut away. Naturally after that sculpture has not only imperfections like pretty rough texture, but also bobbles and completely different texture where sprooses were cut off. On y this piece I myself chewed al, imperfections with all my tootles. I used files for metal and big warier you of chasing elements for metal on my Dremel. (Rotary tool similar to what dentists are using to repair cavities).
And this is not done yet. Another almost last step will be to make a patina over bronze. Patina is done by using a water based solution with some addition of different acids. Each type of acid in connection with Cupo or, lead and zinc (components of bronze) are giving different colors after high heat is applied to a patina. Liquid acid can be applied with the brush or sprayed and torch is used to heat bronze surface. Exactly at the time of heating bronze is having fast reaction to an acid and is getting the color you are expecting. After piece cooled down I have to kelang extra powder from a surface robbing bronze all over. When surface is clean, now I use a rag and robe a soft wax over the patina. Wax protects bronze from additional quick pagination from acids in the air.
Now piece looks like what you see in the photo, but even this is not all. You can not see it on this photo, but I have a pedestal I.attached under my piece from brown-red polished granite. And, believe it or not, it looks beautiful.
Thank you for the patient and reading.
Here I described a professional college course of one year study.
I must add to this. Today we have 3D printers that can do exact copy of this sculpture in about one hour. You only have to add to it pagination.
Grigory Gurevich, copyright, June 8, 2017. SOPRON, Hungary.