Weld Fittings Product Guide

WARNING: Never weld, drill or grind on a tank that has held fuel. Fuel vapors are extremely flammable and explosive. Weld fittings into new, clean tanks only, in a well-ventilated area away from ignition sources. Wear proper welding protection.

Boyd Welding weld fittings come in aluminum, steel and stainless steel, with three thread types: NPT (tapered pipe thread), AN / JIC (37° flare) and ORB (SAE O-ring boss). Use this overview to tell them apart, then open the guide for your thread type.

On this page: How Each Thread Seals | Which Thread Do I Have? | Materials | Guides

How Each Thread Seals

NPT vs AN/JIC vs ORB section views showing where each seals: NPT on the tapered thread flanks with sealant, AN on the 37 degree flare, ORB with an O-ring in the port chamfer

Which Thread Do I Have?

	NPT	AN / JIC	ORB
Thread	Tapered, 1 in 16 on diameter, 60° thread	Straight UNF / UN, 60° thread	Straight UNF / UN, 60° thread
Size is named by	Nominal pipe size (1/8" to 6")	Dash size: tube OD in 1/16" (-8 = 1/2")	Dash size: same threads as AN by dash
Where it seals	On the thread flanks as the taper wedges tight	37° flare cone, metal to metal	O-ring squeezed into the port chamfer
Thread sealant	Required	None	None. The O-ring seals.
How to spot it	Threads get smaller toward the end of the male	Male has a cone-shaped 37° nose	Female port has a chamfer at the top; male has an O-ring
Our fittings	Flanged weld fittings, machined NPT bungs, half and full couplings	AN / JIC male weld fittings	SAE O-ring female weld fittings

Materials

Weld the fitting to a tank of the same metal: aluminum to aluminum, steel to steel, stainless to stainless. All of these fittings are made for fuel, hydraulic and water tanks.

Material	Our fittings
Aluminum	6061 sheet: stamped flanged weld fittings. 6061-T6 bar: machined NPT bungs, half and full couplings, AN / JIC male and SAE O-ring female weld fittings.
Steel	1018 CR flat bar: stamped flanged weld fittings. 1018 bar: machined NPT bungs, AN / JIC male and SAE O-ring female weld fittings.
Stainless steel	316 stainless: stamped flanged weld fittings. 304 stainless bar: all machined stainless fittings, including NPT bungs, AN / JIC male and SAE O-ring female weld fittings.

Protect the threads when you weld. Welding heat and spatter can damage threads. Keep the weld bead and spatter off the threads, and let the fitting cool before you thread anything into it. Weld fittings are not replaced after they have been welded.