How to Weld Sheet Metal Together

This article is aimed at taking you through some basic steps involved with tack welding sheet metal together using a Metal Insert Gas (MIG) Welder, working with 22 gauge sheet metal. Welding like a pro takes a lot of practice; but you should be able to at least weld some basic sheet metal together by following these steps.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• MIG Welder
• Wire welding brush, 60 and 120 grit sand paper
• Heavy Welding Gloves
• Welding face mask (Ideally auto light sensor)
• Long sleeve sweat shirt or jacket
• Grinder, (a Dremel Tool with grinder attachment works well for smoothing out small tack welds)
• Good direct lighting
• Vice grips or other metal clamps you can use to hold the metal together
• Plyers with rubber handle grips
• J-B Weld or Liquid Metal Filler (Optional, if you are not going to do a complete bead weld and want all seams sealed)
• Body metal hammers (Optional, for flattening rough metal edges, if any

1. Set up direct lighting for the work area. Make sure there are no flammable rags or debris in the area and also tell others who may walk in on you that you will be welding. No one should be in the area without proper eye protection.

2. 

   Clamp the sections of sheet metal together, with the object being to have as tight and flush of a seam as possible. You may decide to overlap the metal or possibly line it up evenly next to each other. If this is the case be sure to lay a piece of wood under the seam area to be welded. Be sure your metal edges are level using your hammer to pound down any rough edges.

3. 

   Using your sandpaper or wire brush be sure that the areas to be welded are clean, removing any paint or wax. It is imperative that the area be clean metal or the weld may not stick. Your small grinder can be used here too for any tough spots.

4. 

   Set up your MIG weld settings while the main power is still off. For tack welding 22 gage together I set the welder at minimum power, which is a lower heat setting, and the wire feeder speed at a low setting of around 3. Also attach your grounding clamp somewhere onto the metal, and out of your way.

5. 

   Be sure you have your long sleeves on, heavy gloves, and of course your welding helmet. Run through a test weld before turning the power on, running the tip of the wand along the metal, being sure you will have enough elbow room and space to complete the weld with one easy flow.

6. 

   Turn the welder on and place the wand on an angle to the spot to be welded and while you are holding the wire feed trigger down, being sure the wire will be touching the seam, move the wand slowly across the area, but not too slow or you will burn a hole in the metal. Too fast will leave you nothing but spatter. This is where you will have to practice to get the feel for your welding speed. A proper weld should leave you a weld spot from the melted metal on the top side with heat penetration through to the other side of the metal.

7. Tack welds should be approximately 2 to 3 inches apart from each other, moving as far away from the previous one as possible to the next weld spot, so you don't distort the metal due to excessive heat in the same area. Otherwise, just wait for each weld to cool off before moving on to the next.

8. After all of your tack welds have cooled, in just a few minutes, test the strength of your weld by trying to tug the metal apart. Sometimes it may look like you have a good weld, but in fact, it didn't take at all.

9. 
   Dremel Tool with grinder attachment.

   Using your grinder, carefully level out any welding spatter or high spots so you have a level surface. With 22 gage, which is a thinner metal, a powerful circular grinder can easily burn off your entire weld very quickly. I prefer to use the small grinder attachment on a Dremel tool for more control.

10. 

    Now you can either fill in any open seams with liquid metal or J-B Weld or continue with a bead style weld pattern to fill in the entire seam, waiting for the metal to cool down between welds.

Tips & Warnings

• Practice welding on old metal till you get the hang of it along with what settings will work best for you.
• Always place your ground clamp in a position where the clamp and cable is well out of your way and from the weld area.
• Never weld, even for a moment without your helmet on covering your eyes, and prevent anyone else from coming into your work area without eye protection!
• Remember to keep your wand at an angle as you move it. A direct aim on the metal can burn a hole through it very quickly.
• Be sure there are no flammable materials around your weld area and if welding on a car, always be aware of where the fuel lines, tank and other flammables may be!
• Warn others to keep out of the work area without wearing proper eye protection.
• Always turn the power on the welder off while not in use.

[MidniteWriter]

on 1/30/2008 Great step by step instructions, photos and warnings. Well-written article, 5 stars!