Brass Flare Fittings

Brass flare fittings seal metal-to-metal on a 45-degree cone flared into the tube end, with no gasket or sealant in the joint. Vikay supplies SAE 45-degree flare unions, elbows, tees, flare nuts, seal plugs, cylinder, condenser and gauge adaptors in brass for refrigeration, LPG and instrument service.

A flare joint is chosen where a soft seal would be attacked or where the line must hold gas over years without attention. The tube end is opened out to a 45-degree cone with a flaring tool; the nut pulls that cone against the fitting's matching seat, and the seal is brass on brass.

Vikay's flare range covers double-end and half flare unions and elbows, triple-end and half flare tees, reducing unions, short-neck and long-neck flare nuts, dead (cap) nuts, flare seal plugs, cylinder adaptors, condenser unions, gauge adaptors and general flare adaptors. Bodies and nuts are turned from free-cutting brass to BS 2874 CZ121 / ASTM B16 C36000, to the SAE J513 45-degree flare form, with threads to SAE, BSP or NPT depending on the pattern.

The range is used on refrigeration and air-conditioning circuits, LPG appliance and cylinder connections, refrigerant gauge manifolds, and instrument and fuel lines. Sizes run 1/4 in to 3/4 in flare with matching tube sizes in fractional and metric. Send your flare size, thread and pattern and we will quote.

Frequently Asked Questions

What angle are these flare fittings?

45 degrees, to the SAE J513 form used in refrigeration, air conditioning and gas work. The 37-degree JIC form used in hydraulics is a different standard. A 45-degree nut on a 37-degree cone will start and appear to tighten but will not seal, so check the seat angle before mixing parts.

Do I need sealant or PTFE tape on a flare joint?

Not on the flare face itself. The seal is metal-to-metal between the cone and the seat, and tape or paste on that face prevents proper contact. Sealant belongs only on a tapered pipe thread at the other end of the fitting, if the pattern has one.

Can brass flare fittings be used with R410A and other high-pressure refrigerants?

Flare joints are used with modern refrigerants including R410A, provided the flare is cut square with a good tool, the cone is unmarked and free of burrs, and the nut is torqued to the value the equipment maker specifies rather than by feel. Under-torqued and over-torqued flares are both common leak sources on high-pressure systems.

What is the difference between a short-neck and a long-neck flare nut?

The neck is the parallel skirt behind the thread that supports the tube as it leaves the nut. A long-neck nut spreads bending over more tube length and is preferred where the line vibrates or is routed with a bend close to the joint; a short-neck nut suits tight installations where clearance is limited.

Which adaptors do I need for a refrigerant cylinder or gauge set?

Cylinder adaptors convert a cylinder valve thread to a flare connection, condenser unions join the flare line to the condenser port, and gauge adaptors take a manifold hose onto a service port. Give us the two ends you need to join, with the thread form and size for each side, and we will identify the part number.