Color Cement Handicraft 2

Color Cement Handicraft 2

After a study some years ago of the various forms of producing clay

pottery and its possible relation to school arts and industrial

education, the handicap of necessary firing to give permanency loomed

large against its general adaptation by schools. This resulted in

considerable research and experimenting by the authors with cement and

the use of color in the endeavor to parallel in some measure each of the

methods employed in the making of fired tiles and pottery. Particular

attention was given to simplifying the process of securing permanent

form to many of the plastic forms of schoolroom art, which have been

presented in clay and other perishable mediums. With the projects

presented in the following chapters permanent useful objects can be

secured by students in their school art subjects. Attention was also

given to the enriching or refining by decoration the many objects

heretofore made in cement and concrete by vocational classes. The

problems and methods explained in the following description solve this

need.

 

Craftsmen or amateur home-workers who delight in creating and building

objects of beauty around them can find in color cement a medium which

will appeal to their needs, in that the necessary working equipment is

simple and the work can be done within small space.

 

The following chapters by no means complete the story of color cement.

They record the results of the work of the authors and it is hoped that

it will stimulate interested readers to carry this delightful handicraft

to even greater achievements.

 

The results achieved have been accomplished through several years’

patient experimenting by the authors, but the realization that many

other teachers, craftsmen and students will be aided in continuing this

delightful, durable handicraft, is in itself an enjoyable reward to the

authors for their efforts.

 

Reta A. Lemos

 

Pedro J. Lemos

 

 

 

 

[Illustration]

 

CHAPTER 1

 

Materials and Equipment

 

[Illustration]

 

 

IN THE MAKING OF COLOR CEMENT HANDICRAFT the chief material used is

Portland cement. While this material has assumed a most important part

in the building history of our present time, there are not many who know

its history and source, and as every craftsman is a better craftsman if

he knows something of the story of the material with which he works,

here is the brief story of Portland cement.

 

PORTLAND CEMENT DERIVES ITS NAME because of resemblance in color to a

stone quarried near Portland, England, and it was named by its inventor,

Joseph Aspdin in 1824. It is a manufactured product produced by a

scientific process. At the beginning of the Christian era the Romans

used a natural cement very extensively, and many fragments of color

frescoes and friezes remain from the work of the ancients, showing that

they used color with their work.

 

THE PRINCIPAL INGREDIENTS OF PORTLAND CEMENT are lime, silica, iron, and

alumina. These materials are mixed in definite proportions and then

subjected to a degree of heat that almost causes them to melt, forming a

clinker or slag. This clinker is ground until it is reduced to a powder,

and this is the Portland cement. Portland cement is generally mixed with

an aggregate to produce strength and this aggregate is usually stone,

gravel or sand. The third material needed to complete the combination is

water.

 

SUCCESS IN THE USE OF CEMENT depends largely upon cement that is fresh.

Cement is very sensitive to moisture and if kept where fogs, dew or

moisture of any nature is absorbed into it, the first set or “hydration”

takes place and destroys its use for fine handicraft.

 

TO TEST FRESH CEMENT when the cement sack is open, thrust the hand into

it and see that no hard lumps are in it. Fresh cement will feel

slippery and soapy when rubbed between the finger tips. If it feels

gritty and sandy it may do for the rough parts or body of vases and

tiles, but only fresh cement should be used to mix with color and for

surfacing purposes.

 

THE PROPER CARE OF CEMENT requires that it be kept in a covered

receptacle and kept in a dry place, preferably up from the floor if the

floor is near the ground. It should be kept in a dry, tight work-shop

and the doors should be kept closed at night to avoid any moisture from

the night air reaching it. Nothing can restore spoiled cement and it

should not be used as the results will be discouraging.

 

GOOD GRADES OF AGGREGATES SHOULD BE USED in cement work. Clean sand

should be used and a sand that is not too fine is preferable. Gravel and

crushed rock used in large work such as garden seats, large bowls and

outdoor problems should be of a good grade to form a good mixture.

 

THE WATER USED IN CEMENT WORK should be free from all impurities.

Moderately warmed water will hasten the setting or hardening of cement

while very cold water retards the hardening.

 

THERE ARE TWO COLORS OF CEMENT, gray and white. Portland cement is gray

in color and a white cement is also made that is a refined form of

cement. White cement is not as hard or durable as gray cement, but gives

a smooth surface and sets as satisfactorily as the gray cement. It is

more expensive than the gray cement and should not be used later than

six months after the sack is opened.

 

WHEN CEMENT IS USED ALONE IT IS TERMED “NEAT.” When it is mixed with

rock, gravel or sand it is termed “concrete.” Concrete produces strength

and the neat cement produces a smooth texture and surface. When concrete

is used the cement and water will rise to the top and if the surface is

worked and pressed with a trowel the cement is “flowed” to the top,

producing a smooth surface.

 

MOLDS ARE USED FOR FORMING CEMENT AND CONCRETE, and are made from wood,

metal or plaster-of-Paris. The forms in all instances should be tied or

braced together to prevent the moisture of the mixture from running out,

as the water is essential to the successful hardening of the cement. In

the making of cement pottery and tiles, plaster-of-Paris molds or forms

are generally used and plaster-of-Paris therefore forms an important

material in the making of color cement handicraft.

 

Plaster-of-Paris is made in different degrees of setting periods. These

are quick-setting, medium-setting, and slow-setting. Casting plaster or

sculptor’s plaster should be asked for and a medium-or slow-setting

plaster is preferable for the beginner.

 

CEMENT, AGGREGATES, WATER AND PLASTER FORM THE MAIN PARTS of our working

materials excepting the color, which is especially described in the

chapter on Color.

 

THE EQUIPMENT for concrete pottery is simple, and much of it may be

pressed into service from material to be found about the house or

workshop. Inventive ingenuity on the part of the worker will find clever

uses for many discarded kitchen utensils and unused tools.

 

Following is a list of convenient things needed to produce pottery.

These may be added to or elaborated through personal requirements.

 

WORKING EQUIPMENT.

 

galvanized iron pans about 2 x 3 feet

2 large spoons

4 or 5 pans

2 ladles

1 large file or rasp

2 table knives

3 pieces of ordinary glass about 12 x 18 inches

1 palette knife

1 lb. modeling wax

1 bristle brush ½ inch wide

2 small sable oil brushes, No. 1 or 2

1 small clay-modeling tool

2 pieces of thin wood for mixing paddles

½ doz. small saucers or butter dishes

strips of thin metal

thin soft wire

1 sifter

2 pails

muller and pestle

several pieces of surfaced wood about 12 inches square.

 

With a flat table to work on, running water or a pail of water handy, a

box to receive waste plaster-of-Paris and cement, the proper environment

for color cement is set.

 

GALVANIZED IRON WATER TRAYS can be made by taking a three-inch by

seven-inch sheet and cutting a two-inch strip off of one end, reserve

for making scrapers and other useful tools. Cut the remaining metal into

three rectangular sections for trays.

 

To make the trays, lay one of these pieces over a strong box with an

even edge and hammer into tray shape as shown in the accompanying plate.

The corners should be bent so as to make the trays waterproof without

soldering. A wooden mallet should be used for hammering the metal as a

metal hammer may cut the metal.

 

MOLDING CASE. Several pieces of board hinged together with one series of

edges coming so that they will rest evenly on a flat surface, will

produce an adjustable case to use in making molds. A strong cord will

keep it in place. A strip of metal (tin, brass or iron) may be used as

a cylinder, the circumference being pressed in and tied to conform to

the dimensions of the object to be molded.

 

MIXING PADDLES. Paddles for mixing plaster or cement can be made out of

firm wood strips and handles shaped to fit the hand.

 

INCISING TOOLS. A nail hammered into a piece of firm wood and the head

snipped off with nippers then sharpened with a file or emery stone until

it is a tapering wedge point. Nut picks may be filed down slightly for

this purpose. Two or three points of varying widths will be handy to

have, particularly when some of them disappear occasionally as all small

tools will.

 

SCRAPER. A piece of barrel stave or heavy wire bent like a croquet

wicket with a wire fastened from end to end is particularly convenient

where a number of clay or plasticene tiles are to be produced. For class

use two strips of wood are fastened to the bench, the desired width

separating the strips. Between these strips a piece of strong paper

should be laid and the clay or plasticene pressed firmly onto it between

the strips. The scraper will shave the surplus clay if it is moved along

so that the wire rests on the wooden strips. Measure off the six-inch or

eight-inch squares, cut across with a knife from strip to strip and

remove the squares by sliding the paper out. This will give a smooth,

even surface on which to model or incise designs.