If you can choose to add arc welding or gas welding in the workshop, most tinkers find that small AC arc devices are inexpensive and versatile equipment. However, for the remote outdoor chores that occasionally occur around most farms, natural gas is almost the only practical option. (Of course, there are portable welding machines available. You can use a workshop unit and a generator bag... But either method represents a considerable investment, especially if the equipment is only used infrequently. Repair on site.)

As it happens, the researchers at Mother EARTH NEWS encountered quite a lot of remote welding work in our eco-village property-from fixing the wind power plant frame to the sealed hydropower plant pipe-these work for the Lincoln automatic feeding device It is completely inaccessible. They like it better. Therefore, it didn’t take long for a member of our team to get tired of installing both the generator and the arc welding machine on the pickup truck. He started to put together some odds and ends around the store to make his own portable DC arc welding machine. .

The experimenter Dennis Burkholder decided-after finding an old lawn mower, an idle Delco-Remy car alternator, and a tired but usable 12-volt deep-cycle battery-he Almost owns the manufacture of portable, intermittent-duty, low-voltage, welding machines. Sure enough, after trying several different combinations of scrap components, he came up with the cheapest (and strangest-looking) arc welding machine ever assembled.

Basically, the welding machine is powered by approximately 50 amps that a Delco-Remy alternator can generate. .. And adjust by changing the speed of the lawn mower engine. But a 12-volt battery is needed to balance the surge that occurs when the arc is hit or disconnected. In addition, Dennis found that by placing two 1 1/2 ohm, 8 amp resistors in series with the alternator's magnetic field, reducing the field voltage to about 6 volts, the setup worked more smoothly. (In fact, without these two resistors, arcing would almost kill the 3-HP Briggs & Stratton engine!)

Considering that almost all parts of the project have been removed, the welding machine has a very wide range of uses. On the one hand, for smooth sheet metal work, DC capability is usually the first choice, and our lawn mower device can reverse its polarity to change its arc penetration and splash quality! However, the function of this tool has some limitations. First, the maximum heat of the arc is about 50 amps, so the device will not penetrate the steel more than about 1/4". In addition, it is best not to use the welding machine for more than 20 minutes at a time to avoid overheating the alternator (the thermal overload switch will Tell you when it is enough).

Finally, the low-voltage DC current of the device has both advantages and disadvantages compared with traditional AC power sources. Because the voltage of the circuit determines the distance of the spark jump, the electrode used in our portable welding machine must be steadily close to the surface of the workpiece to maintain the arc. However, because it is a DC welding machine, the welding rod will hardly get stuck.

Of course, the most shocking thing about Dennis's welding machine is its low cost. The only component our researcher was forced to buy was a resistor, and he found it in the nearest auto parts store. And—even if the warehouse of your precious discards is not ours—you should still be able to buy resistors, wires, switches, pulleys, and V-belts for less than $20. Think about it carefully, a DC arc welding machine with a built-in trolley for 20 dollars may be a special offer for this year's workshop!

Good idea, Ford has a 200-amp alternator. Just need to figure out how to adjust the engine speed

This is to make a 

I like all the barn buildings, wooden houses, and solar energy.

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