It is, of course, impossible to give costs in an empirical way. In the first place, improved methods of generating the two gases are still being advanced, as well as improved apparatus for production and storage. The prices of raw material fluctuate, and the cost of labor is increasing irregularly. But most serious, no two men are likely to use the same amount of gas nor take the same time for a specific job; nor would one workman be apt to repeat his performance. It at once appears, that outside of catalog prices for apparatus, cost estimating is as difficult as in the printing trade.

I have given cost data at several points which must be taken with a little salt. Before purchasing oxy-acetylene plants, it would always be in order to get estimates and statements from the several firms handling this line; these should advise the kind of outfit for the work at hand.

The table of costs worked out by the Davis-Bournonville Company is appended.

Approximate Cost Of Oxy-Acetylene Welding

Oxygen at 3 cents, acetylene at 1 cent per cubic foot; labor 30 cents per hour.

Tip number

Thickness of metal

Consumption of acetylene per hour

Consumption of oxygen per hour

Proper pressure in pounds for oxygen

Lineal feet welded per hour

Cost of labor per hour

Total cost per hour

Cost per lineal foot

1

1/32 to 1/16

2.8 feet

3.6 feet

8 to 10 lbs.

50 feet

$0.30

.436

.0087

2

1/16 to 3/32

4.5 "

5.7 "

10 to 12 "

30

0.30

.516

.0172

3

3/32 to 1/8

7.5 "

9.7 "

12 to 14 "

25 "

0.30

.666

.0266

4

1/8 to 1/4

11.7 "

15. '.'

14 to 18 "

16 "

0.30

.867

.054

5

1/4 to 5/18

18.

23. "

18 to 22 "

10

0.30

1.17

.117

6

5/16 to 7/16

25.

32. "

20 to 25 "

7 "

0.30

1.51

.216

7

7/16 to 1/2

32.5 "

41.5 "

22 to 27 "

5 "

0.30

1.87

.374

8

1/2 upward

48.5 "

62. "

24 to 30 "

2.64

The following table1 is intended to show the costs and efficiency of the three principal welding flames. Costs are figured on the basis of generator acetylene one cent a foot; compressed acetylene, two and one-half cents; oxygen, three cents; hydrogen, one cent; coal gas, one and one-quarter cents. I have reduced the estimated temperatures to reasonable limits.

Oxy-acetylene mixture

Oxy-hydrogen mixture

Oxy-coal gas mixture

Number of B. T. U. obtained by complete combustion of one cubic foot of gas......

1570

290

616

Temperature (Fahr.) obtained by combustion of the mixture (Approx) .................

30000 C.

20000 C.

17000 C.

Cubic feet of oxygen required to burn one cubic foot of gas to obtain the best welding flame (from practical tests made) ....................

1.302 1.703

0.25

0.67

Cubic feet of oxygen required to obtain 1000 B. T. U.

with a welding flame.....

0.765 2 1.003

0.86

1.09

Cubic feet of heat-producing gas required to obtain 1000

B. T. U. with a welding flame ...................

0.59

3.44

1.63

Cost of 1000 B. T. U. (cents)

2.892 3.593 (generator acetylene)

3.782 4.39 3 (dissolved acetylene)

5.92

4.20