Propane Portable 4,000/9,000/18,000 BTU/Hour

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There are two types of welding that we will talk about, arc welding and oxy-acetylene. The latter will also include some pertinent information on cutting torches and fabrication of parts and tools.

But we will first cover some basics dealing with arc welding. It is a positively charged electrode and a negatively charged steel plate commonly called a ground complete a circuit at the end of a welding rod. When the rod is held a given distance from the item to be welded, the current jumps the gap creating an enormous amount of heat. The heat melts the rod end and a puddle of liquid metal will result which can be controlled to make a weld.

There are many types of arc welding. A few are carbon-arc, metal-electrode, gas metal-arc, atomic-hydrogen, MIG, TIG, and many others. For our purposes we will focus on two basic types of arc welding; AC and DC. It is difficult to explain the difference in simple, down to earth terms so let’s just settle for some of the main differences and advantages of each.

AC (alternating current) is probably the most common and most economical of welders. The distinct advantage that AC arc welding has is that there is virtually no magnetic blow, which causes excessive splatter and uncontrollable arcs. The basic features are a good forceful arc, an easy arc to maintain once it is begun. It is great for heavy steel plating because of deep penetration. The negative factors are that the initial arc can be difficult to start and that burn- throughs on thinner plates of metal can be a frustrating problem. All in all though, a simple AC welder is a good all around tool for general repairs.

DC, or direct current, provides for a more variety in welding. Direct current, by nature, can be manipulated in ways completely different than the alternating cycles of AC. One example of this is that by changing the polarity of current flow different welding characteristics can be realized. Straight polarity, when the current flows from the rod to the base metal, provides a fairly standard arc for a variety of metals. Reversed polarity, when the current flows from the base metal to the rod, provides for 2/3 of the total heat to be centralized in the welding rod tip. This superheats the electrode metal and shielding gas from the flux causing the molten metal to travel at a high velocity resulting in very deep penetration to the base metal. These variations in the types of DC units can accommodate welding on thick or thin metals. This can give quite a bit of flexibility when trying to avoid burn-throughs with thinner base metals or working on deeper weld penetration on thicker plates.

There are many articles on the different types of welding rods/electrodes and their welding characteristics that you can fine on the internet.

As with any trade there are certain hazards which must be addressed when arc welding.

•  Avoiding radiation from the arc, ultraviolet and infrared rays
•  Flying sparks, globules of molten metal
•  Electrical shock
•  Fumes
•  Burns

Protective clothing and specialized eye protection must be used in order to reduce these risks. An arc-welding helmet with protective lens reduces the amount of harmful eye radiation and protects the head from splatter and heat. The hair, hands, arms and other skin surfaces must be covered, preferably with heavy leather to shield out other harmful radiation produced by the intense arc. Don’t wear regular coverings like heavy cotton or wool as arc welding is accompanied by flying sparks and molten metal pieces that will ignite such clothing. Also avoid pants with cuffs, tennis shoes, thin gloves, and shoes with thin soles.

Avoid electrical shock by working on a dry floor with thick rubber shoes and by wearing dry leather welding gloves. Also make sure to use insulated electrode holders and have the equipment properly grounded. Keep the area properly ventilated to avoid inhaling the burnt fumes. The fumes generated in the welding process may contain highly toxic metal oxides. Keep in mind that you are welding with molten metal. The arc is hot, the metal is hot, and everything in contact with the metal is hot. Watch for falling metal globules; they burn quickly through tennis shoes and unprotected pants. When done welding use tongs to pick up the metal; it does not cool quickly and even when quenched in water beware of the superheated steam it produces when dipped and the heat it retains when removed.

Above all be aware of others around you. When an arc is struck to start welding the sudden flash can cause severe eye damage to onlookers.

More on oxy-acetylene welding in a later revision.

THE DRIVE SHAFTS AND U-JOINTS: the jeep drive shafts are all 7/8″ diameter steel bar stock with machined in keyway slots. Woodruff keys index the u-joints to the slots in the shafts. The shaft lengths vary by application. To circumvent typical obstacles (crossmembers, exhaust, clutch linkage, etc), a common application will have two shafts, three u-joints, and a center support bearing. For example the early CJ uses a 27 3/8″ front shaft and a 22″ rear shaft. The jeep truck, jeep wagon, or jeep sedan delivery uses a 31.5″ long front shaft and a 17.75″ rear.

Three different jeep universal joints are used in each setup. The front u-joint has one 7/8″ opening with a 3/16″ keyway and one 7/8″ opening with a 1/4″ keyway. The center u-joint has one 7/8″ opening with a 1/4″ keyway and one 7/8″ opening with a 1/4″ keyway. The rear u-joint has one 7/8″ opening with a 1/4″ keyway and one 1″ opening with a 1/4″ keyway. Note all shafts use 1/4″ keyways, but the winch uses a 3/16″ keyway and the PTO, which uses the 1/4″ keyway has a larger 1″ output shaft.

Sagging  in the center from length wise down the top(running from front to rear) and sagging across the center going (running from side to side) are major repairs. Stiffeners can be used on the inside of the top. They can be either bent 3/4″ aluminum box tubing or number one lumber,1 x 2′s or 2 x 2′s arched to fit the Original Bend(s). Surface preparation at this point is essential. Round off the outside corners of the stiffener because fiberglass does not like sharp corners.

The next step is attaching the stiffeners to the inside of the fiberglass top. Use a total five flat head wood screws for each wood stiffener and five metal flat head screws for the aluminum.  Drill the holes from the outside of the top into the stiffener. Mix up some bondo and apply between the stiffener and fiberglass. Set the first two screws lightly and temporarily using a flat washer under each head to hold in place then set all five without washers. Let set until hardened. Apply fiberglass and resin, smooth, sand and paint.

MORE TO COME!