HOMESTEAD WELDING

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If you decide to acquire gas welding equipment, check out machinery auctions for the best buys on used items. (As far as I can determine, a now welding and cutting apparatus—with accessories but minus gas tanks—now runs $150 and up-MOTHER.)

OK, let's say you just went out and bought an oxyacetylene outfit and are about to use it for the first time. Before you do anything else, make sure you have on heavy leather welders' gloves and that your shaded goggles are on your forehead. Too many good craftsmen have destroyed their eyesight by not wearing such glasses for oxyacetylene work.

You should also see that the two gas tanks are very securely fastened to their handtruck, or attached to the wall with a good strong chain. The oxygen is under high pressure and acetylene is extremely combustible, so be careful not to let the containers fall. And remember, absolutely no smoking around oxyacetylene equipment.

Before using the outfit, it's always a good idea to open the valve on each tank at least a quarter turn in order to blow out any dust or dirt that may have collected on the fittings. This step is called "cracking the tanks".

(After a while, incidentally, you'll learn what pure acetylene smells like. This will help you locate any leaks in your equipment. The soapsuds method is about the best way to check for escaping gas when you hook up fresh tanks. Make sure the torch valves are closed and the tank valves open during this test.)

Next, hook up the regulators. The oxygen connections have right-hand threads, while those for the acetylene are left-handed. The green hose is for oxygen, the red for acetylene. (You can remember the difference by associating "red" with "fire".) Secure all fittings with an open-end wrench . . . not the adjustable or crescent type, which has a habit of chewing the daylights out of the brass connections.

Welding is carried out at various pressures according to the work to be done. For steel 1/8" to 3/8" thick, I usually run the acetylene to the hose at about 7 to 10 psi (pounds per square inch). The oxygen is held at about 25 to 30 psi, since an oxygen-acetylene ratio of between three to one and five to one is the general rule.

Here's how to set pressure: Open the valves on the regulators by screwing them all the way out (make sure those on the torch are closed). Then open the valves on the gas containers until the regulators' tank pressure gauges 'register "medium". The point when this is reached will vary according to the surrounding temperature: The pressure in the receptacles will be higher at 80° than at 50°. To get hose pressure, screw in the regulator valve until the desired psi value is reached.

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