How to Achieve Leak-Free Steel Welds

Leak-free welds are particularly important in shipbuilding.

Leak-free steel welds are descriptive of high-quality steel welds, the kinds of welds that all technicians, students and novices should aspire to. While welding technicians typically have a pretty good handle on producing welds that can hold water or gas, novices and students will have to practice regularly to make sure their welds are clean, solid and of high enough quality to be leak-free.

Things You'll Need

• Welding equipment
• Wire brush
• Clamps
• Welding helmet

Instructions

1. Set up the welding equipment for the type of metal being worked on. Different types of steel require different filler metals. For instance, chromoly steel works well with Spoolarc 65 welding wire, while mild steel can be welded with 70S-6, which is a very basic welding filler.

2. Set up the welder with the correct current and wire speed for the thickness of the steel you are working with. The settings will differ depending on the welder you are using. For this reason, many manufacturers of welding equipment print this information in a table that can be found either on the inside panel of the welder or in the owner's manual. Once the correct current and wire speed are set up, turn on the welder.

3. Attach the negative ground clamp to the work piece approximately six inches from the location you will be welding. One of the most important aspects of attaining a leak-free weld is to ensure good conductivity between the welding electrode and the ground clamp. For this reason, and at this point, you will also want to thoroughly clean the surfaces of the steel with a wire brush. This will remove most surface contamination that could produce a low-quality weld.

4. Clamp the steel parts together in the configuration in which they will be welded. There should be as little gap as possible between the steel pieces.

5. Lower your welding helmet into position and turn on the welding machine. Position the welding electrode approximately 1/4-inch from the part of the weld that is closest to you. This will allow you to push the weld puddle rather than attempting to push the weld, which causes poor weld penetration.

6. Touch the welding electrode to the metal being welded and watch as the weld puddle is formed. Once it has reached approximately 1/4 inch across, begin moving the weld electrode in tiny circles, moving from one piece of steel to the other. Strive to keep the weld as straight and tight as possible and avoid hurrying. If you rush, the weld may not penetrate deep enough into the surrounding steel, causing a leak.

7. Remove the weld electrode after you have finished the weld. Clean the weld slag off the weld with a wire brush and carefully scrutinize your work. If you can see light through any part of the weld, you have experienced what is called "burn through." This is the result of allowing the electrode to stay in one place too long. If, on the other hand, you find that the weld you produced looks trim and melts evenly into the surrounding metal, you should find that the weld is entirely leak-free.

Tips & Warnings

• If you are unfamiliar with welding, you may find it best to wear a long-sleeved shirt and gloves when you weld. While the slag will not technically harm you, it can be very uncomfortable to deal with.

• Always wear a welding helmet when you weld. Not only does it prevent hot slag from striking your face, but it protects your eyesight from potentially severe flash burns caused by light from the welding electrode.

References

• "Welding Complete: Techniques, Project Plans & Instructions"; Editors of CPi; 2009
• "Welder's Handbook, Revised: A Guide to Plasma Cutting, Oxyacetylene, ARC, MIG and TIG Welding"; Richard Finch; 2007
• "Welding Manual"; John Haynes; 1995