How to Stick Weld Thin Metal

Sheet metal may be welded with basic arc welding equipment.

Stick welding thin metal is a useful way of joining thin metal sheets or shapes with an inexpensive home welding machine, or in an industrial setting when other means of joining are unavailable or inappropriate. However, stick welding tends to be hotter than other methods, and thin metal is prone to unwanted melting during welding. These properties mean that joining thin material by stick welding must be done with great care and preparation.

Things You'll Need

• Safety glasses
• Grinder or file
• Clamps
• Brass bar (optional)
• Welding rods
• Welding machine
• Welding helmet
• Chipping hammer

Instructions

Prepare the Metal for Welding

1. Remove any contamination on the surface using a grinder or file. The metal around the weld joint should appear bright and shiny and be free of any rust, grease or loose material.

2. Fit the metal parts together very well and make sure there are no gaps. Any gaps will need to be filled during welding, increasing heat input and the possibility of distortion.

3. Brace the material with clamps to hold it in position. When the metal cools after welding it will shrink unevenly. Bracing and clamps will help it hold the desired shape.

4. Clamp a strip of thick brass along the back side of the joint if you can. Brass will not mix with steel and will support the liquid metal, preventing it from dripping and making a hole. A brass backing strip is not necessary, but it will help.

Prepare the Rods and Machine

1. Select 1/16-inch or 3/32-inch welding rods compatible with the metal to be welded. The 1/16-inch rods will minimize heat input. The 3/32-inch rods are larger and require more heat but are more widely available. E6013 rods in the 1/16-inch size will work on most steel and require between 20 and 45 amps.

2. Test the power level by welding a piece of metal similar to the prepared material. Increase the power of the welding machine until it will form a stable arc without putting too much heat into the metal.

3. Choose a spot on the material to place the ground clamp. Narrow sections of thin material do not conduct electricity well. Choose a wider section, if possible, and make sure the clamp makes good contact.

Tack Weld and Weld

1. Weld 1/4-inch welds at the corners and every 12 to 18 inches along the seams. These "tack" welds will hold the material in place during welding and will help minimize distortion.

2. Chip the slag off the tack welds. Removing slag from previous welding will help prevent defects and weakness.

3. Weld the metal, but only small amounts at a time. Heat buildup during welding can cause holes and distortion. Wait for the material to cool before welding in the same area twice.

Tips & Warnings

• Always use eye and face protection. Welding arcs can cause sunburn and eye damage. Welding produces hot slag chips and liquid metal spatter. The minimum protection for welding is both a welding helmet and safety glasses.

• Weld as little as possible. An inch of weld every six inches may be strong enough. If a watertight seam is necessary, it may be better to use caulking instead of welding fully.

• Weld other areas while you wait for a weld to cool. Holes caused by overheating are difficult to fill with stick welding. Be patient.

• Welding creates may hot sparks. Remove all flammable material from the area where welding will take place.

• Arc welding uses potentially dangerous voltage and amperage. Do not operate welding equipment if you are inexperienced or uncertain how to do it safely.

References

• Pro-Weld Services: Shielded Metal Arc Welding (SMAW) Stick Welding Rod Selector