The solder preform may include the solder flux needed for the soldering process. Another difference between brazing and soldering is how the solder is applied. Lead-free solder glasses with soldering temperature of were also developed. Such hydrogen plasma can be used for fluxless reflow soldering. This sort of torch can also be used for soldering and brazing. Electronic connections may be hand-soldered with a soldering iron. Leads may be soldered either manually or by a wave soldering machine. Some JST surface-mount headers are designed to handle higher temperatures of reflow soldering. The boards are then conveyed into the reflow soldering oven. Other applications include ultrasonic welding, wave soldering, and sputtering targets. There are a variety of soldering techniques used to attach components to a PCB. Copper and nickel tend to form intermetallic layers during normal soldering profiles. Ceramic capacitors may experience changes to their electrical parameters due to soldering stress. Lead free soldering requires higher soldering temperatures than lead/tin soldering. Tallow can be used as flux for soldering.