Aircraft Welding

Acetylene

This is the primary fuel for oxy-fuel welding and cutting. It is chemically very unstable, and is stored in special cylinders designed to keep the gas dissolved. 

Cylinder color maroon

Argon

______is a colorless, odorless, tasteless, and non-toxic inert gas. Inert gas cannot combine with other elements. It has a very low chemical reactivity and low thermal conductivity. 

Color of the cylinder Grey

Helium

_______ is a colorless, odorless, tasteless, and non-toxic inert gas. Its boiling and melting points are the lowest of the elements and it normally exists only in gas form. It is used as a protective gas shield for many industrial uses including electric arc welding.

Color of cylinder Brown

Hydrogen

_________ is a colorless, odorless, tasteless, and highly flammable gas. It can be used at a higher pressure than acetylene and is used for underwater welding and cutting. It also can be used for aluminum welding using the oxyhydrogen process.

Color of Cylinder Orange

Oxygen

________ is a colorless, odorless, and nonflammable gas. It is used in the welding process to increase the combustion rate which increases the flame temperature of flammable gas.

Color of cylinder Green

Pressure Regulators

_______ is used to lower the cylinder pressure to the desired working pressure.  Regulators have two gauges, one indicating the pressure in the cylinder and the second showing the working pressure. 

welding hose

A __________ connects the regulators to the torch. 

200 psi

The hose should have the date of manufacture, maximum working pressure of ______. 

check valve

The __________ stops the reverse flow of the gas and can be installed either between the regulator and the hose or the hose and the torch. 

flashback arrestor

A ___________installed on each hose prevents a high pressure flame or oxygen-fuel mixture from being pushed back into either cylinder causing an explosion. 

Equal Pressure Torch 

It has a mixing chamber and uses acetylene fuel at 1–15 psi. The flame is easy to adjust and there is less chance of flashback with this torch. 

Injector Torch 

The injector torch uses fuel gas at pressures between just above 0 and 2 psi.

Cutting Torch 

The cutting process is fundamentally the rapid burning or oxidizing of the metal in a localized area. The metal is heated to a bright red color (1,400 °F to 1,600 °F), which is the kindling temperature, using only the preheat jets. 

torch tip

The _______ delivers and controls the final flow of gases. It is important that you use the correct tip with the proper gas pressures for the work to be welded satisfactorily. 

Welding Eyewear 

Protective eyewear for use with oxy-fuel welding outfits is available in several styles and must be worn to protect the welder’s eyes from the bright flame and flying sparks. 

Torch lighters

are called friction lighters or flint strikers. The lighter consists of a file-shaped piece of steel, and a replaceable flint, which when drawn across the steel produces a shower of sparks to light the fuel gas An open flame or match should never be used to light a torch, because accumulated gas may envelop the hand and when ignited cause a severe burn. 

Filler Rod 

The use of the proper type of filler rod is very important for oxy-acetylene welding. In some cases, a suitable rod with a lower melting point helps to avoid cracks caused by expansion and contraction. Welding rods may be classified as ferrous or nonferrous. Ferrous rods include carbon and alloy steel rods, as well as cast-iron rods. Nonferrous rods include brass, aluminum, magnesium, copper, silver, and their various alloys. 

Gas Cylinders 

All cylinders should be stored and transported in the upright position, especially acetylene cylinders, because they contain an absorbent material saturated with liquid acetone. 

Regulators 

Prior to installing the regulator on a gas cylinder, open the cylinder shutoff valve for an instant to blow out any foreign material that may be lodged in the outlet. Close the valve and wipe off the connection with a clean oil-free cloth.

Hoses

Connect the red hose with the left-hand threads to the acetylene pressure regulator and the green hose with the right-hand threads to the oxygen pressure regulator.

Connecting Torch

Connect the red hose with the left-hand thread connector nut to the left-hand thread fitting on the torch. Connect the green hose with the right-hand thread connector nut to the right-hand thread fitting on the torch.

Select the Tip Size

The higher the number, the bigger the hole in the tip, allowing more heat to be directed onto the metal and allowing thicker metal to be welded or cut.

Adjusting the Regulator Working Pressure 

The working pressure should be set according to the manufacturer’s recommendation for the tip size that is being used to weld or cut.

Lighting & Adjusting the Torch

With the proper working pressures set for the acetylene and oxygen, open the torch acetylene valve a quarter to a half turn. Direct the torch away from the body and ignite the acetylene gas with the flint striker.

Oxidizing Flame 

The _________ burns at approximately 6,300 °F and is produced by burning an excess of oxygen. It takes about two parts of oxygen to one part acetylene to produce this flame.

Neutral Flame

burns at approximately 5,850 °F at the tip of the inner luminous cone and is produced by a balanced mixture of acetylene and oxygen supplied by the torch. 

Carburizing Flame 

urns at approximately 5,700 °F at the tip of the inner core. The flame is produced by burning more acetylene than oxygen, and can be recognized by the greenish feathery tip at the end of the cone. The _________ is best used for welding high-carbon steels, for hard facing, and for welding such nonferrous alloys as aluminum, nickel, and Monel.