Color Cement Handicraft 5

Color Cement Handicraft 5

THE FIRST PROBLEMS IN CEMENT should be the casting of cement tiles

without the use of color. As a beginning problem set the retaining bars

around a six-inch square space and mix a neat mixture of cement and pour

into the space so as to make about a quarter-inch layer. After this has

set for about fifteen minutes pull some of the neat cement up the sides

with a putty knife or strip of cardboard and then pour in the remainder

of the tile concrete mixture of one-third cement and two-thirds sand.

This will result in a tile with the top and sides surfaced with neat

cement. The surfaces of the bars and the glass or other under surface

have of course been properly oiled previous to the pouring.

 

BEFORE PROCEEDING WITH TILE MAKING it may be necessary to make a number

of plaster bars to use as retaining walls. These are made as follows:

Two strips of wood one-half inch to an inch thick laid parallel on a

glass or other smooth surface that has been greased with oil. The

distance between the strips of wood should be about ten inches, as the

length will then serve for producing eight-inch tiles or any size under

this dimension. The edges of the wood facing inward should always be

oiled, the wood strips are held in position by small lumps of modeling

wax pressed firmly into the outer edge of the wood so that it attaches

it to the surface of the glass. This will leave a channel between the

two wooden strips into which the plaster is poured. The two ends of the

channel may be stopped with blocks of wood or blocked with wax or clay.

As soon as the plaster is poured into the mold it should be evened by

running a straight strip of wood or metal over it spanning the width of

plaster. Run this back and forth to trim off the surplus, so that the

plaster will have an even thickness when removed from its bed.

 

TO REMOVE THE PLASTER first remove the wooden strips and then tap the

layer of plaster lightly on the edge with a hammer. This will loosen it.

Then with a T square and sharp nail mark off bars five-eighths inch

wide and also bars one and one-quarter inches wide. At least twelve bars

of each width should be made. After drying for three days the bars may

be sawed apart with any sharp saw, care being taken to hold the saw

within the groove made by the nail. The edges of the bars may be further

smoothed if necessary with a knife or file.

 

STRIPS OF WOOD WITH SURFACED SIDES can be used in the place of plaster

bars and if oiled will release very easily from the plaster when used as

retaining walls.

 

TO MAKE AN INCISED TILE in plain cement proceed as follows: Roll out

clay or modeling wax to about one-half inch thickness and cut to the

desired size of tile. Cover this smooth surface, place a design which

has been made on thin paper and trace with a pencil. The paper should be

held so as not to slip and the result should be a slight indentation of

the design on the clay. These lines are then incised over with the

incising tool to the desired depth, care being taken that no

over-hanging edges remain on the edges of the incisions. The incisions

should have sides slightly sloping inward and if the tool is correctly

shaped it will produce such lines.

 

THE DESIGN should be planned to be at least one-half inch from edge and

simple in construction. Avoid a tangle of ever crossing lines. A

geometrical arrangement dividing the square into pleasing spaces will

produce the best results.

 

Place the tile on a level surface and take four bars of the one and

one-fourth inch plaster strips or wood, soak in water for fifteen

minutes, wipe dry and oil. Now place the four bars so that the inside

edges are against the wax or clay tile and fasten so that they are

unmovable with modeling wax. The bars if placed with one end projecting

past the bar meeting it at right angles permits their adjustment to any

size tile under ten-inch dimensions. Onto this pour plaster-of-Paris,

pour into the center letting it run toward the edges forcing all air

ahead of it as it enters the incisions. Level off surface and remove the

plaster cast from the mold as soon as it has hardened.

 

TO RELEASE THE PLASTER CAST first remove the surrounding bars and lift

the plaster tile off the clay. The plaster tile will have the design in

relief on the surface. If any clay is adhering to these relief lines, it

is evidence that there are overhanging edges and such edges should be

trimmed with a knife before the next step. The next step is as follows:

After plaster tile is dry put it in water for a few minutes, then oil

the surface well. Place back in the bars and repeat previous operations

excepting that this time a cement mixture is used instead of plaster. A

mixture of neat cement should be used half way up and permitted to

remain for five minutes before the concrete (one-third concrete,

two-thirds sand) is poured in for the remaining half.

 

IN MIXING SAND AND CEMENT it should be remembered that they should be

mixed together thoroughly _while dry_ before any water is added. After

the cement has been poured into the form, if it is to be used for floor

or wall purposes, four small squares of cardboard should be pressed into

the exposed cement which is the back of the tile. This should be done

about fifteen minutes after the cement has been poured, when it is not

too soft.

 

The tile may be removed after it has remained in the form for

twenty-four hours. A thin cement mixture of another color may be made

and brushed over the tile and the surplus removed, leaving the last

color only in the incisions.

 

AN INTERESTING VARIATION is produced by cutting away the clay or wax

between the incisions of the pattern to the depth of one-half inch or

less, making a mold of this tile and in turn casting a concrete tile.

The result will be a surface with relief section and low spaces, the

relief being concrete and rough in texture.

 

These low spaces are then filled with a colored cement of another color,

or neat cement, and brought to the level of the relief surface. Such a

tile secures a pattern adaptable to tile walks, or any surface which is

subjected to wear, in that the design is not only a thin surface layer,

but a thick portion of color that will not disappear with the wearing of

the surface layer.

 

A SIMPLE METHOD OF MAKING TILE MOLDS is to cut a design from a thick

piece of cardboard or sections of a design, and glue these in proper

position to carry out a design arrangement. These pieces should be cut

with tapering sides so as to permit of proper “draught” or releasing

conditions when the plaster cast is made for mold purposes.

 

The pieces of cardboard should remain glued until dried to avoid the

moisture of the soft plaster moving the parts around.

 

WITHOUT THE USE OF COLOR a number of pleasing and varying textures can

be secured with plain cement, as the gray color of the cement has an

artistic quality, and it is well to become well grounded in the use of

cement before combining color with it.

 

SEVERAL WAYS OF USING PLAIN CEMENT FOR TILES beside those already given

are explained in the following descriptions. These are termed Traced

Cement, Burnished Cement, Scraped Cement, Concrete Tile, Cement and

Concrete Tile, Glazed and Dull Cement Tile, Glazed Relief Line Tile.

 

THE TRACED CEMENT TILE is made by pouring a half-inch mixture of

concrete (one-third cement, two-thirds sand) into a mold made with the

usual retaining bars of any desired dimensions. Over this concrete

mixture a layer of about one-quarter of an inch of sifted neat cement

mixed with water should be placed. At a certain degree of hardness this

layer of neat cement will yield to a slight indentation or traced

outline. This condition can be tested by touching the edge of the

surface with a pencil point to see whether it is too hard or too soft.

A good plan is to pour the mixture in the evening and it is generally in

right consistency to work upon on the following morning. The surface

should be nearly hard but still sensitive to pressure with a point.

 

HAVING PREPARED THE DESIGN on a piece of paper about the weight of

business writing paper, the design is placed on the surface of the tile

and kept in the same location while a blunt, soft lead pencil is traced

over the pattern, pressing firmly to create a good indented line in the

cement surface. The design for this work is best where the pattern is

easily expressed in lines or outlined forms. The forms can be increased

in strength by rubbing the pencil on the outer edge of the lines to be

slightly modeled in separate appearance. When the design has been

completely gone over, the tile is placed in water for several days,

after which it is dried and a thin coating of color wash (see chapter on

Surface Finishes) may be added to it which will further the pattern by

coloring the traced lines.

 

THE BURNISHED CEMENT TILE is produced by casting a similar tile to the

one made for the Traced Cement Tile and proceeding in the same manner,

excepting that the spaces between the forms are burnished smooth with

the dull pointed pencil or a smooth small stick. This results in some

parts being burnished or pressed down while others remain in slight

relief. A change in this is also produced by scraping the smooth surface

off between the lines in certain places instead of burnishing it. This

results in parts of the surface being of a different texture and also of

a little different color, as the scraped parts are different in both

these respects to the cement which has dried and remains untouched on

the surface.

 

A SECOND BURNISHED TILE EFFECT is to pour a layer of neat cement first

in the mold and a concrete mixture last. When this is hard enough to

remove, and still soft enough to work upon (the neat cement layer having

been in the bottom will dry with a dull finish and not a glaze finish

as when flowed on as a top layer) it should be removed and the design

traced upon this neat cement surface. If a leather tool or smooth hard

point is used, certain parts as desired can be worked upon, smoothed

down or pressed in, through the paper which will create a change of

surface texture.

 

THE SCRAPED CEMENT TILE is where either the top neat cement or bottom

cement layer has the design in line or form scraped out of the cement,

the entire design being produced without a plaster mold being used. A

sharpened nail or nut pick will make a good scraper and this scraping

and pressing is done on the cement surface direct and not through a

paper as in the two previous problems. This direct method of working

upon cement surface is considered more thoroughly and more extensive

applications made of it in the chapter on Carved and Modeled Cement.

 

THE CONCRETE TILE. Varying finishes may be secured in casting any cement

tile by the kind of aggregate used with the cement. A rough irregular

small crushed rock will give one kind of texture, while a round small

white gravel will give another and each change will present different

effects. Without going into extremes of finishes or having too many

changes in the surface of a tile, pleasing effects can be secured by one

to three changes of texture secured by putting different mixtures in

different parts. This may be done by mixing and applying with a brush or

spoon the different mixtures into the mold, placing the mixtures each in

their proper section of the mold. The whole is then covered with the

backing mixture resulting in the surface pattern appearing with the

changes after the tile has been released from the mold.