As the name suggests, weld on fittings are pre-manufactured fittings made from either aluminium, mild steel or stainless steel that can be welded onto automotive or car components to produce a finished product.
Often it is quicker and cheaper to purchase a weld on fitting rather than make one or have one made, especially if it is a standard fitting such as a filler neck with a cap, anodized caps are available as well as plain steel or aluminium.
As an example, Norden Hydraulics has weld on fittings to complete catch tanks, fuel tanks, radiators, header tanks, sumps and even dry sumps.
These fitting include necks, or necks with caps and billet radiator necks. Many come in a variety of sizes, materials and in male or female depending on the application.
There are also pushlock tails to weld to a pipe or tank to then be fitted with a hose, such as is commonly used for breather fuel line fittings.
For inlet manifolds, there are injection bosses available to weld into the manifold so that you can then add fuel injectors.
Norden Hydraulics range of weld on fittings come in stainless steel that can be MIG or TIG welded, Mild Steel that can be MIG, TIG, brazed, silver soldered or sometimes arc or even oxy welded, and aluminium that can be MIG or TIG welded.