A practical manual of oxy acetylene welding and cutting

Some ten years ago, the author started a welding shop, using the oxy-acetylene process. He hardly knew how to light the torch, much less its operation. In this respect he was on an equal footing with a few other venturesome individuals in this country who had embarked in the same business, regarding which practically nothing was known. It follows that there were many failures and disappointments.

The author can well testify that "there is no royal road to learning," and yet in offering this treatise he is prompted by the belief that the man who goes ahead may smooth out some of the rough spots, and thereby assist those who come after. The book is sold at a price which precludes the possibility of profit to the author. You pay only for the printing and the paper the subject-matter is gratis. Do not look a gift horse in the mouth too closely.

What is Acetylene?
A hydro carbon gas composed of equal volumes of carbon and hydrogen. By weight it is composed of 93% carbon and 7% hydrogen.

When was it discovered?
In 1836 by Davy, an English chemist, and Berzelius, a Swiss chemist. From what is Acetylene obtained?

What is Calcium Carbide?
It is a substance, hard like rock, of a grayish color, and possessing a slight crystalline structure.

When was it discovered?
In 1892 by an American chemist, named Willson, at 'Spray, N. C.

How is it manufactured?
Lime and coke in the proportion of 56 parts by weight of the former to 36 parts of the latter are fused or melted together in an electric furnace. It is cooled and crushed and is then assorted as to size by means of screens.

How is Acetylene obtained from Calcium Carbide?
When calcium carbide and water are brought together, acetylene is formed. This is accomplished as follows: The calcium in the calcium carbide combines with some of the oxygen in the water and forms first calcium oxide or quick lime, and then calcium hydroxide (slacked lime). The carbon in the calcium carbide combines with some hydrogen from the water to form acetylene, the chemical symbol of which is C 2 H 2 .

Is there more than one method of bringing the Carbide and water together
Yes, there are three methods.

Name them.
First, water to carbide; second, recession; third, carbide to water.

Explain each method.
The "water to carbide" method consists in allowing water, drop by drop, to fall upon a body of carbide. This was the earliest method of generating acetylene and its adoption was due to the fact that it was easier to control the flow of water than it was the feeding of the carbide; especially as the carbide first put on the market was not uniform as to size.

The "recession" method consists in al- lowing water to rise, coming in contact with either a mass of carbide or successive layers of carbide.

The "carbide to water" method consists in feeding the carbide in small amounts into a large volume of water.

Which is the best?
The "carbide to water."

Why?
After generation is impossible and purer gas is produced. Again when carbide and water are brought together heat is evolved. Now this heat can be considerable, sometimes reaching 1000 F., or it can be negligible, depending entirely upon the amount of water. If there is a sufficient amount of water both the carbide and the water will be kept cool. It has been found that if for each pound of carbide, one gallon of water is supplied, the temperature is kept down in fact, cannot possibly exceed 212 F., and in practice never goes that high. The "carbide to water" method is the only one that guarantees a sufficient amount of water to assure cool generation.