Deposited metal and number of passes
How much metal has to go into the groove, how much wire or how many electrodes that costs, and how many passes it breaks into. Estimating and shift planning both start here.
How it works it out
Cross-section. For a single V:
F = b·s + tan(α/2)·(s − c)², increased by 10 % for the cap. For a
double V the same, over two half thicknesses. For a fillet
F = z²/2, again with the 10 % addition.
Deposit. The area in mm² times one metre gives the volume
in cm³, and that times the density of 7.85 g/cm³ gives the mass. Hence the
handy rule: kg/m = F · 0.00785.
Consumable. The deposit divided by the deposition efficiency of the process: a covered electrode yields about 65 % of its own mass (the rest is coating and stub), solid wire under gas over 90 %.
Efficiency and deposition rate
| Process | Efficiency | Rate, kg/h | Pass area, mm² |
|---|---|---|---|
| MMA (111) | 0.65 | 1.3 | 25 |
| MIG/MAG (131/135) | 0.93 | 3.2 | 35 |
| Flux-cored (136/138) | 0.85 | 4.2 | 45 |
| TIG (141) | 0.95 | 0.6 | 12 |
The calculator gives arc hours. A real shift also holds fit-up, tacking, turning the work, cleaning and changing electrodes: the arc burns for 25–35 % of a shift on MMA and 40–55 % on a wire feeder. The full time with overheads comes from the cost per metre calculator.
What it is for
- Estimating. Deposit mass times material price is the most predictable part of what a joint costs.
- Ordering material. Kilograms for the whole structure, rather than “grab two packs”.
- Choosing the preparation. Run the same joint as a V and as an X — the difference in deposit and passes can be a factor of two. The type comes from the groove preparation calculator.
Frequently asked questions
Why do I end up with more passes than the calculator says?
Because the first pass is always thinner. The root goes in as a narrow bead at low current so it does not blow through or hang a drop — its area can be half that of a fill pass. The calculator divides the whole area by one pass area, so in practice add one pass.
Where do I get the area of one pass?
Measure it on a macro section of your own test piece — the only honest route, because it depends on current, travel speed and how you carry the torch. The values filled in here are typical for the process and are a starting point, not a rule.
Is this the same as the cost per metre calculator?
The geometry is the same — both work the cross-section from one formula so the two never disagree. There, prices, gas, electricity and labour are added on top; here what is left is the metal and the planning: how much deposit, how many passes, how many arc hours.
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