How is weld metal weight calculated?

First the cross-sectional area of the bead is found from the joint geometry, then it is multiplied by the weld length to get a volume. Multiplying the volume by the filler density gives the deposited weight. Carbon steel is about 7.85 grams per cubic centimetre.

What is the difference between deposited and purchased weight?

Deposited weight is the metal that ends up in the joint. Purchased weight is larger because spatter, slag, and electrode stubs waste filler. Dividing deposited weight by the deposition efficiency gives the amount you must actually buy.

What deposition efficiency should I use?

Typical figures are about 65 percent for stick, 82 percent for flux-cored, 90 percent for MIG, and 98 to 99 percent for TIG and submerged arc. Stick is lowest because of stub loss and slag, while submerged arc recovers almost all the wire.

How is a fillet weld area computed?

For an equal-leg fillet the theoretical triangle area is half the leg squared. This tool adds a 10 percent allowance for the convex reinforcement that a real bead carries above the theoretical face, giving a more realistic consumption estimate.

Is this accurate enough for procurement?

It gives a solid first estimate for ordering wire or rod and for cost analysis. Real consumption varies with welder technique, fit-up, and reinforcement, so add a contingency margin and verify against measured usage on production runs.

Weld Bead Volume & Filler Metal Weight

Knowing how much filler metal a job will consume drives both the purchase order and the labour estimate. This tool computes the cross-sectional area of the most common joint shapes, scales it by weld length and filler density to get deposited weight, then adds back process losses to give the weight you actually need to buy.

How it works

Every estimate starts from the bead cross-section. The areas, with all dimensions in millimetres, are:

Fillet (equal leg z):   A = 0.5 x z^2 x 1.10      (10% convexity)
V-groove:               A = root x t + t^2 x tan(angle/2)
U-groove:               A = root x t + R x t
J-groove:               A = root x t + 0.5 x R x t

where t is groove depth, R is the root radius, and angle is the included groove angle. Multiplying area by weld length gives the deposited volume, and volume times density gives deposited weight:

weight = area x length x density
purchased = deposited / deposition_efficiency

Example and notes

An 8 mm fillet, 1000 mm long, in carbon steel: area is 0.5 x 8^2 x 1.10 = 35.2 mm^2, volume is 35.2 cm^3, deposited weight is about 0.276 kg. With MIG at 90 percent efficiency you would buy roughly 0.307 kg of wire.

The 10 percent fillet allowance reflects a normal convex face; flat or concave beads consume less.
Densities used: carbon steel 7.85, stainless 8.00, aluminium 2.70 grams per cubic centimetre.
For multi-pass grooves the total area is what matters, so enter the full groove depth rather than a single pass.