Plumbing tubing & pipes use “IN-side-diameter” in relation to their fittings.

So, a 3/4″ plumbing pipe needs a fitting that is called 3/4″ but actually has a 7/8″ inside diameter.

Typically, quality plumbing fittings are an “M’ thickness the same as used in some air conditioning applications.

 

Plumbing Copper fittings are used in hot and cold water lines in plumbing systems when making connections to copper pipe. There are two basic types of copper pipe or tubing: rigid and flexible. Copper fittings can be used with both types of copper pipe. Rigid pipe is generally installed in new homes and provides a neater installation. Flex copper pipe is best for repair work since it can be run around obstacles without connections or cuts.

Solder  at temperatures below 840°F is required to securely connect a copper fitting to a copper pipe. Solder is a fusible metal alloy that, when melted, joins two or more metals together in a process known as soldering.

Soldering procedures

For low-temperature connections, The connections produced by solder are liquid and gas tight At low pressure
Solder at temperatures below 840°F is required to securely connect a copper fitting to a copper pipe. Solder is a fusible metal alloy that, when melted, joins two or more metals together in a process known as soldering.

For low-temperature connections, The connections produced by solder are liquid and gas tight At low pressure

Copper fittings must be cleaned on the interior and exterior prior to being soldered. Soldering a copper fitting with debris on it will result in a poor seal. Using a Tu-Turn copper fitting brush will ensure a clean copper fitting.

Soldering paste or ‘flux’ should be applied to a copper fitting after it has been cleaned. Flux will keep the copper from oxidizing when heated. This provides a firm bond between the copper and the solder. A quality soldering iron is needed to join the copper pipe and the fitting. Once the copper fitting has been properly prepared, it can be bonded to a copper pipe by using a quality soldering torch

When soldering, do not overheat or you will boil away the flux and the solder will not “draw” into the void between the fitting and pipe.

There are many different types of copper fittings, each serving a particular function.

For More info on sizes see Nominal Size Conversion Guide Professional Plumbing Technicians Glossary