Tricks for Welding Stainless Hats

Types of Caps

• Stainless steel caps are often used, but other alloys are used to cap pipes as well. Carbon steel also does not rust and works well to seal the end of a pipe. Nickel alloy is workable and will not deteriorate over time, but it's sensitive to temperature and can crack or become weak in extreme cold.

Accurate Dimensions

• When you are preparing to weld the end on a pipe, make sure you have the right-size cap. Though you can make up for a small difference, the cap should fit snugly to ensure a proper seal. As you work around the area where the cap meets the pipe, make sure the line where the cap meets the pipe stays straight. If the cap becomes askew, liquid can seep through.

Check the Welding Temperature

• Different metals have different welding temperatures. Make sure the pipes you are dealing with can handle the heat of the flame by checking the metal's melting point in a reference text. Welding is dependent on the metals melting and then cooling back together. If the melting points of the metals are vastly different, the weld will not be strong.

Bevel the Entrance

• Beveling the end of the pipe allows you to use a smaller cap, providing a very tight seal. Beveling is done by scraping the edge of the pipe so it gradually gets smaller as you get close to the edge of the pipe. The cap then slips on the end more easily but remains snug at the edge of the fitting. Start the beveling at the point where the cap will end on the pipe.

Integrity of the Pipe

• Before working with any welding material, verify the integrity of the pipe by visually inspecting the surface. If the piping has been compromised, the welding can cause a full blowout. If the pipe seems thoroughly intact, with no weakened spots, you are more likely to have a successful capping experience. If the pipe is beginning to wear down you might have issues securing the cap without causing leaks elsewhere.