Introduction: Make a Carbon Arc Torch for Your 220 Volt Stick Welder
MIG welders can do many things, but they cannot heat metal for bending or brazing. Your stick welder can do those things with a carbon arc torch added to it.
I am using a torch already fully constructed, so you will not see the parts aside from their place in the final unit.
2 pieces of 1 x 2 firring strip 6 inches long (each)
2 pieces of 1/4 inch steel rod 7 inches long (each)
2 1/4 inch water pipe nipples 2 1/2 inches long (each)
2 #8-32 thumb screws about 1/2 inch long each
2 #8-32 nuts
2 1/4 inch flat washers
2 pieces of steel 1/8 inch thick and 3/8 inch x 3/4 inch
2 crimp-on connectors for #10 stranded wire
2 #8 terminal screws from an old electrical outlet
1 compression spring about 1/2 inch in diameter and 2 inches long
1 nylon cable tie about 6 inches or more long
8 #8 round head wood or flat head sheet metal screws
20 feet of #10 stranded plastic or rubber covered copper wire
2 pieces of scrap steel or aluminum 1/16 to 1/8 inch thick and 1 1/2 x 1 1/2 inches (each)
1/4 inch carbon rods (Get at a welding supply house.)
Drill press and bit assortment
Crimping tool for electrical terminals
Soldering iron (150 watt) or gas torch and solder
Begin by cutting the wooden handles from the firring strip--6 inches long each.
Step 1: Make the Wooden Handles
Cut two pieces of 1 x 2 inch pine, like a firring strip. Make them 6 inches long each.
Step 2: Prepare the Handles for the Hinge
The handles are hinged at the rear end of the torch. The side with the single screw is free to move. The 1 1/2 x 1 1/2 pieces of aluminum or steel are fastened with two screws to the other handle. The side out of view to the camera is a mirror image of what is shown here. Leave the single screw a tiny bit loose so the hinge action moves freely. (The hole you see in the aluminum is left over from a previous life.)
Step 3: Prepare the Handles for the Spring and Nylon Tie
Using the torch will involve squeezing it with one hand. You want the spring to gently push the handles open when the pressure from your hand is released. But, you do not want them to open without limitation. So, a nylon cable tie goes through the center of the spring and around the bottom of the handles to restrict how far the handles can open.
Close the handles and drill a hole about 3/16 of an inch through both. The nylon tie will go through these holes later, but not right away. Open the handles wide and drill a 1/2 inch countersink hole on the inside face of each handle. These holes are for the ends of the spring.
Wait to install the spring and nylon tie until after the next step.
Step 4: Drill the Ends of the Handles for the Steel Rods
The holes for the steel rods should be straight and parallel to each other so the tips of the carbon rods will touch when the handles are squeezed together during use of the torch. A drill press or similar assistance for drilling holes parallel to the outer surfaces of the handles is a big help, although it may be possible to get pretty close with a hand-held drill. These holes should be about 1 1/2 inch deep into the ends of the handles.
Weld a flat washer on each steel rod. Insert the rods into the handles. Drill for a locking screw on each handle. This screw fixes the rods so they cannot shift or rotate from your setting of their angle.
Now place the spring into the countersink holes on the inner surfaces of the handles. Hold the handles together lightly and insert the nylon tie so it goes through the spring. Slip the end of the nylon tie through its own retaining hole and adjust the tension on the nylon tie for the amount of space you want between the handles when they are not being squeezed. Trim the nylon tie so the extra is removed. You may want to heat the cut end of the nylon tie with a match so it loses its sharp edge. Sometimes those can scratch and cut. (See the previous panel for the photo there.)
Step 5: Weld the Nipples to the Rods
If you can get black iron nipples, so much the better for welding. If you can get only galvinized, grind away the zinc coating wherever you will be welding and do not breathe any fumes. Do your best to align the nipples to the steel rods before welding so the center of both nipples is on the same plane as much as possible. This will be important for making the tips of the carbon rods meet when the handles are squeezed together during use of the torch. Some discrepancies can be overcome by bending the 1/4 inch steel rods a little.
Nipples are a little larger than their nominal sizes. You may want to run a 5/16 inch drill bit through the nipples. This would allow using 5/16 inch carbon rods for a bit more heat, although I have always been able to do anything I need to do with 1/4 inch carbon rods. Besides, it is not always easy to find 5/16 inch carbon rods.
Drill a 3/16 inch hole in the side of the nipples near the lower end (as when the torch is in use). Place a #8-32 nut over the hole and weld it in place. The nut's threads will likely distort a little during welding. Chase the threads with a #8-32 thread tap. Screw the thumbscrews into the nuts.
A 1/4 inch carbon rod is shown in the nipple ready for use in the photo.
Step 6: Add Tabs for Electrical Connections
Weld steel tabs 3/8 x 3/4 inch to the 1/4 inch steel rods for the electrical connections. Be careful to check their position before welding so the tabs will not touch and short out the torch when the handles are squeezed. Drill each tab and thread for #8-32 screws. Brass screws from old electrical outlets work very well, although you may need to chase the ends of their threads with the thead chaser on your crimping tool.
Cut the 20 foot piece of #10 stranded wire in two halves. Crimp the connectors on each 10 foot piece of #10 stranded copper wire and attach the wire to the tabs.
Step 7: Secure the Wire
Another smaller nylon tie can be very helpful for securing the wires as they pass under the handle as you see in this photo. Use electrical tape every foot or so to keep the two wires together.
Strip the other ends of the wires back about an inch and tin each with solder to keep them from fraying.
When you are using the torch, either wire will be held by the welder's ground clamp and the other will be held by the electrode holder (stinger). There is no polarity to be of concern. Keep the electrode holder and the ground clamp separated from one another so there will be no unwanted sparks.
Step 8: Insert the Carbon Rods and Align Their Tips
You need about two inches of carbon rod extending from each nipple at the very minimum. This keeps the actual torch from becoming too hot. With the welder's power off, adjust the carbon rods so they meet each other when the handles are squeezed together. Bend the 1/4 inch steel rods slightly as necessary to insure the tips meet.
During use you will need periodically to stop and readjust the position of one or the other of the carbon rods because one invariably burns faster than the other. I find I can do this easily while wearing welder's gloves.
Step 9: Using the Torch
This is how your finished torch should appear.
Put on your welding helmet and gloves. Set your 220 volt welder between about 70 and 90 amps for 1/4 inch carbon rods, depending on how much heat you need for your job. (115 volt welders do not have the power or duty cycle needed to operate a carbon arc torch.)
Be careful that the torch does not touch anything conductive once the welder's power is on. When you need to put the torch down, you can leave the welder running, but turn the torch upside down and set it onto a piece of plywood or a clean, non-metalic workbench surface.
Flip your helmet down with the snap of your neck. Squeeze the handles together until the tips of the carbon rods touch. Hold them together for a couple of seconds so they can heat up. Then gently relax your grip just a little so the tips have a gap between them, and a brilliant blue arc will form between the tips of the carbon rods. It will be very, very hot. You will soon get a sense of how much to spread the tips.
Keep the arc moving over the steel you want to heat. If held in one place too long, little pools of molten metal will form and you could even burn or blow through your work. I find it works best to heat a small area on a piece I want to bend and then pull part of the bend I want to make. Then I heat the area next to what I bent until it is ready to pull. If something does not go quite right, heat it again and bend to correct.
If you are brazing something, heat the metal until it is hot enough to melt the brazing rod.
A carbon arc torch does not use gas flowing under pressure, like an oxy-acetylene torch. You do not need to worry much about small parts being blown out of position.
A carbon arc torch greatly expands the versatility of your 220 volt stick welder. Some people use the flame of a carbon arc torch the way one might use the flame of an oxy-acetylene torch to make metal form a pool. Then they add welding rod to weld as they would with a gas welder. I have read that it is possible to use only one carbon rod. The ground clamp goes on the work and the single carbon rod acts like a spot welder. I tried this once, but the pieces of metal were not clamped tightly enough to make it work.