If silver alloy is used, brazing can be referred to as ‘silver brazing’. Colloquially, the inaccurate terms “silver soldering” or “hard soldering” are used, to distinguish from the process of low temperature soldering that is done with solder having a melting point below 450 °C (842 °F), or, as traditionally defined in the United States, having a melting point below 800°F or 425°C. Silver brazing is similar to soldering but higher temperatures are used and the filler metal has a significantly different composition and higher melting point than solder. Likewise, silver brazing often requires the prior machining of parts to be joined to very close tolerances prior to joining them, to establish a joint gap distance of a few micrometres or mils for proper capillary action during joining of parts, whereas soldering does not require gap distances that are nearly this small for successful joining of parts. Silver brazing works especially well for joining tubular thick-walled metal pipes, provided the proper fit-up is done prior to joining the parts.